Welcome to the Pycom forum Forum
    • \[\[global:header.categories\]\]
    • \[\[global:header.recent\]\]
    • \[\[global:header.tags\]\]
    • \[\[global:header.popular\]\]
    • Login

    Explore Pybytes | Official Documentation | Report a Firmware Bug/Issue | GitHub

    External SD Card

    Scheduled Pinned Locked Moved MicroPython
    sd card
    22 Posts 6 Posters 8.7k Views 6 Watching
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • M Offline
      Manju2391 @robert-hh
      last edited by

      @robert-hh @livius
      I did change the values according to pycom sources but still its not liking it. I'm getting this error
      File "/flash/sd.py", line 9
      File "/flash/lib/sdcard.py", line 54, in_init_
      File "/flash/lib/sdcard.py", line 79, in init_card
      File "/flash/lib/sdcard.py", line 147, in cmd
      Typeerror: extra positional arguments given

      robert-hhR 1 Reply Last reply Reply Quote 0
      • robert-hhR Offline
        robert-hh @Manju2391
        last edited by

        @manju2391 It seems that this library is a little bit outdated. I know that I used this on an esp8266, and it worked. And the version on the micropython.org site seems to be a little bit more recent. (https://github.com/micropython/micropython/tree/master/drivers/sdcard). I can check, but not before the evening, which is in about 8 hours.

        M 1 Reply Last reply Reply Quote 0
        • M Offline
          Manju2391 @robert-hh
          last edited by

          @robert-hh
          Is there any possibility to interface the SD card over shared SPI bus without using any
          libraries? I have been getting my head around the SPI module from last week and I haven't got it yet. Not a problem @robert-hh you can let me know how it goes after testing

          robert-hhR 1 Reply Last reply Reply Quote 0
          • robert-hhR Offline
            robert-hh @Manju2391
            last edited by robert-hh

            @manju2391 I tried that driver, and I got it to the point where it showed some activity. The code is below. The sdcard SPI is connected to:
            P9 (SS), P10(Clk), P11(MOSI) and P12 (MISO). It is started with:

            import sdcard, machine, os
            
            sd = sdcard.SDCard(machine.SPI(0), machine.Pin("P9"))
            os.mount(sd, "/card")
            

            But it is very unstable, runs at low speed only, and data read from the card contains the byte sequence "\x7f\x04" here and there. And sometimes lopy simply crashed. So it's nothing really usable at the moment.
            I tried that with two different SD card adapters. One with embedded bus drivers, which is like the one you have, and one which is simply wiring. The latter runs well when connected to the genuine SD card pins of the xxPy, using the built-in SD card module.

            """
            MicroPython driver for SD cards using SPI bus.
            
            Requires an SPI bus and a CS pin.  Provides readblocks and writeblocks
            methods so the device can be mounted as a filesystem.
            
            Example usage on xxPy:
            
                import machine, sdcard, os
                sd = sdcard.SDCard(machine.SPI(0), machine.Pin("P9"))
                os.mount(sd, '/sd2')
                os.listdir('/sd2')
            
            
            """
            
            from micropython import const
            import time
            
            
            _CMD_TIMEOUT = const(100)
            
            _R1_IDLE_STATE = const(1 << 0)
            #R1_ERASE_RESET = const(1 << 1)
            _R1_ILLEGAL_COMMAND = const(1 << 2)
            #R1_COM_CRC_ERROR = const(1 << 3)
            #R1_ERASE_SEQUENCE_ERROR = const(1 << 4)
            #R1_ADDRESS_ERROR = const(1 << 5)
            #R1_PARAMETER_ERROR = const(1 << 6)
            _TOKEN_CMD25 = const(0xfc)
            _TOKEN_STOP_TRAN = const(0xfd)
            _TOKEN_DATA = const(0xfe)
            
            
            class SDCard:
                def __init__(self, spi, cs):
                    self.spi = spi
                    self.cs = cs
            
                    self.cmdbuf = bytearray(6)
                    self.dummybuf = bytearray(512)
                    for i in range(512):
                        self.dummybuf[i] = 0xff
                    self.dummybuf_memoryview = memoryview(self.dummybuf)
            
                    # initialise the card
                    self.init_card()
            
                def init_spi(self, baudrate):
                    master = self.spi.MASTER
                    self.spi.init(master, baudrate=baudrate, phase=0, polarity=0)
            
                def init_card(self):
                    # init CS pin
                    self.cs.init(self.cs.OUT, value=1)
            
                    # init SPI bus; use low data rate for initialisation
                    self.init_spi(100000)
            
                    # clock card at least 100 cycles with cs high
                    for i in range(16):
                        self.spi.write(b'\xff')
            
                    # CMD0: init card; should return _R1_IDLE_STATE (allow 5 attempts)
                    for _ in range(5):
                        if self.cmd(0, 0, 0x95) == _R1_IDLE_STATE:
                            break
                    else:
                        raise OSError("no SD card")
            
                    # CMD8: determine card version
                    r = self.cmd(8, 0x01aa, 0x87, 4)
                    if r == _R1_IDLE_STATE:
                        self.init_card_v2()
                    elif r == (_R1_IDLE_STATE | _R1_ILLEGAL_COMMAND):
                        self.init_card_v1()
                    else:
                        raise OSError("couldn't determine SD card version")
            
                    # get the number of sectors
                    # CMD9: response R2 (R1 byte + 16-byte block read)
                    if self.cmd(9, 0, 0, 0, False) != 0:
                        raise OSError("no response from SD card")
                    csd = bytearray(16)
                    self.readinto(csd)
                    if csd[0] & 0xc0 != 0x40:
                        raise OSError("SD card CSD format not supported")
                    self.sectors = ((csd[8] << 8 | csd[9]) + 1) * 2014
                    #print('sectors', self.sectors)
            
                    # CMD16: set block length to 512 bytes
                    if self.cmd(16, 512, 0) != 0:
                        raise OSError("can't set 512 block size")
            
                    # set to high data rate now that it's initialised
                    #self.init_spi(100000)
                    #self.init_spi(40000000)
            
                def init_card_v1(self):
                    for i in range(_CMD_TIMEOUT):
                        self.cmd(55, 0, 0)
                        if self.cmd(41, 0, 0) == 0:
                            self.cdv = 512
                            #print("[SDCard] v1 card")
                            return
                    raise OSError("timeout waiting for v1 card")
            
                def init_card_v2(self):
                    for i in range(_CMD_TIMEOUT):
                        time.sleep_ms(50)
                        self.cmd(58, 0, 0, 4)
                        self.cmd(55, 0, 0)
                        if self.cmd(41, 0x40000000, 0) == 0:
                            self.cmd(58, 0, 0, 4)
                            self.cdv = 1
                            #print("[SDCard] v2 card")
                            return
                    raise OSError("timeout waiting for v2 card")
            
                def cmd(self, cmd, arg, crc, final=0, release=True):
                    self.cs(0)
            
                    # create and send the command
                    buf = self.cmdbuf
                    buf[0] = 0x40 | cmd
                    buf[1] = arg >> 24
                    buf[2] = arg >> 16
                    buf[3] = arg >> 8
                    buf[4] = arg
                    buf[5] = crc
                    self.spi.write(buf)
            
                    # wait for the response (response[7] == 0)
                    for i in range(_CMD_TIMEOUT):
                        response = self.spi.read(1, write=0xff)[0]
                        if not (response & 0x80):
                            # this could be a big-endian integer that we are getting here
                            for j in range(final):
                                self.spi.write(b'\xff')
                            if release:
                                self.cs(1)
                                self.spi.write(b'\xff')
                            return response
            
                    # timeout
                    self.cs(1)
                    self.spi.write(b'\xff')
                    return -1
            
                def cmd_nodata(self, cmd):
                    self.spi.write(cmd)
                    self.spi.read(1, write=0xff) # ignore stuff byte
                    for _ in range(_CMD_TIMEOUT):
                        if self.spi.read(1, write=0xff)[0] == 0xff:
                            self.cs(1)
                            self.spi.write(b'\xff')
                            return 0    # OK
                    self.cs(1)
                    self.spi.write(b'\xff')
                    return 1 # timeout
            
                def readinto(self, buf):
                    self.cs(0)
            
                    # read until start byte (0xff)
                    while self.spi.read(1, write=0xff)[0] != 0xfe:
                        pass
            
                    # read data
                    mv = self.dummybuf_memoryview[:len(buf)]
                    self.spi.write_readinto(mv, buf)
            
                    # read checksum
                    self.spi.write(b'\xff')
                    self.spi.write(b'\xff')
            
                    self.cs(1)
                    self.spi.write(b'\xff')
            
                def write(self, token, buf):
                    self.cs(0)
            
                    # send: start of block, data, checksum
                    self.spi.read(1, token)
                    self.spi.write(buf)
                    self.spi.write(b'\xff')
                    self.spi.write(b'\xff')
            
                    # check the response
                    if (self.spi.read(1, 0xff)[0] & 0x1f) != 0x05:
                        self.cs(1)
                        self.spi.write(b'\xff')
                        return
            
                    # wait for write to finish
                    while self.spi.read(1, 0xff)[0] == 0:
                        pass
            
                    self.cs(1)
                    self.spi.write(b'\xff')
            
                def write_token(self, token):
                    self.cs(0)
                    self.spi.read(1, token)
                    self.spi.write(b'\xff')
                    # wait for write to finish
                    while self.spi.read(1, 0xff)[0] == 0x00:
                        pass
            
                    self.cs(1)
                    self.spi.write(b'\xff')
            
                def count(self):
                    return self.sectors
            
                def readblocks(self, block_num, buf):
                    nblocks, err = divmod(len(buf), 512)
                    assert nblocks and not err, 'Buffer length is invalid'
                    if nblocks == 1:
                        # CMD17: set read address for single block
                        if self.cmd(17, block_num * self.cdv, 0) != 0:
                            return 1
                        # receive the data
                        self.readinto(buf)
                    else:
                        # CMD18: set read address for multiple blocks
                        if self.cmd(18, block_num * self.cdv, 0) != 0:
                            return 1
                        offset = 0
                        mv = memoryview(buf)
                        while nblocks:
                            self.readinto(mv[offset : offset + 512])
                            offset += 512
                            nblocks -= 1
                        return self.cmd_nodata(b'\x0c') # cmd 12
                    return 0
            
                def writeblocks(self, block_num, buf):
                    nblocks, err = divmod(len(buf), 512)
                    assert nblocks and not err, 'Buffer length is invalid'
                    if nblocks == 1:
                        # CMD24: set write address for single block
                        if self.cmd(24, block_num * self.cdv, 0) != 0:
                            return 1
            
                        # send the data
                        self.write(_TOKEN_DATA, buf)
                    else:
                        # CMD25: set write address for first block
                        if self.cmd(25, block_num * self.cdv, 0) != 0:
                            return 1
                        # send the data
                        offset = 0
                        mv = memoryview(buf)
                        while nblocks:
                            self.write(_TOKEN_CMD25, mv[offset : offset + 512])
                            offset += 512
                            nblocks -= 1
                        self.write_token(_TOKEN_STOP_TRAN)
                    return 0
            
            M N 2 Replies Last reply Reply Quote 1
            • M Offline
              Manju2391 @robert-hh
              last edited by

              @robert-hh
              Thanks for your reply robert and I'll try working on it today and will post if anything crashes up and I have one more doubt regarding the WLAN access point. I have created an access point and I want to connect to my AP whenever the boot.py loads up. I can connect as a station but not as an access point i tried using this syntax but whenever it boots up it's looking for wlan AP but couldn't find it and goes to deep sleep mode. My network is up and it runs when I run it externally but not during boot up.

              from network import WLAN

              wlan.init(mode=WLAN.STA_AP,ssid='AP')
              wlan.init(ssid='AP',auth=(WLAN.WPA2,'xxxx'))
              print(wlan.ifconfig())

              Is the above syntax right?

              robert-hhR 1 Reply Last reply Reply Quote 0
              • robert-hhR Offline
                robert-hh @Manju2391
                last edited by

                @manju2391 About WLAN: It could look like:

                from network import WLAN
                
                wlan = WLAN(mode=WLAN.STA_AP)
                wlan.connect(ssid='AP',auth=(WLAN.WPA2, 'xxxx'))
                # from here on it's optional. It just takes a few moments to connect
                for _ in range (200):
                    if wlan.isconnected():
                        print(wlan.ifconfig())
                        break
                    else:
                        time.sleep_ms(50)
                else:
                    print("Could not connect")
                
                M 1 Reply Last reply Reply Quote 0
                • M Offline
                  Manju2391 @robert-hh
                  last edited by

                  @robert-hh

                  I tried using SPI bus it is very slow. I had designed the pcb with spi pins but looks like it is not best so I’m just using the SDIO pins and changed the pcb. About the WLAN when I define wlan initially it is asking me for ap ssid at first I get an error saying ap ssid not given. I get the IP address when run locally and it connects to FileZilla but when it boots for the STA_AP it doesn’t print the IP address nor it connects to WLAN. It will be in idle state. I don’t know why it’s not connecting. I’m wondering should we create a station first and then an AP?

                  1 Reply Last reply Reply Quote 0
                  • N Offline
                    nathanh @robert-hh
                    last edited by nathanh

                    @robert-hh said in External SD Card:

                    """
                    MicroPython driver for SD cards using SPI bus.
                    
                    Requires an SPI bus and a CS pin.  Provides readblocks and writeblocks
                    methods so the device can be mounted as a filesystem.
                    
                    Example usage on xxPy:
                    
                        import machine, sdcard, os
                        sd = sdcard.SDCard(machine.SPI(0), machine.Pin("P9"))
                        os.mount(sd, '/sd2')
                        os.listdir('/sd2')
                    
                    
                    """
                    
                    from micropython import const
                    import time
                    
                    
                    _CMD_TIMEOUT = const(100)
                    
                    _R1_IDLE_STATE = const(1 << 0)
                    #R1_ERASE_RESET = const(1 << 1)
                    _R1_ILLEGAL_COMMAND = const(1 << 2)
                    #R1_COM_CRC_ERROR = const(1 << 3)
                    #R1_ERASE_SEQUENCE_ERROR = const(1 << 4)
                    #R1_ADDRESS_ERROR = const(1 << 5)
                    #R1_PARAMETER_ERROR = const(1 << 6)
                    _TOKEN_CMD25 = const(0xfc)
                    _TOKEN_STOP_TRAN = const(0xfd)
                    _TOKEN_DATA = const(0xfe)
                    
                    
                    class SDCard:
                        def __init__(self, spi, cs):
                            self.spi = spi
                            self.cs = cs
                    
                            self.cmdbuf = bytearray(6)
                            self.dummybuf = bytearray(512)
                            for i in range(512):
                                self.dummybuf[i] = 0xff
                            self.dummybuf_memoryview = memoryview(self.dummybuf)
                    
                            # initialise the card
                            self.init_card()
                    
                        def init_spi(self, baudrate):
                            master = self.spi.MASTER
                            self.spi.init(master, baudrate=baudrate, phase=0, polarity=0)
                    
                        def init_card(self):
                            # init CS pin
                            self.cs.init(self.cs.OUT, value=1)
                    
                            # init SPI bus; use low data rate for initialisation
                            self.init_spi(100000)
                    
                            # clock card at least 100 cycles with cs high
                            for i in range(16):
                                self.spi.write(b'\xff')
                    
                            # CMD0: init card; should return _R1_IDLE_STATE (allow 5 attempts)
                            for _ in range(5):
                                if self.cmd(0, 0, 0x95) == _R1_IDLE_STATE:
                                    break
                            else:
                                raise OSError("no SD card")
                    
                            # CMD8: determine card version
                            r = self.cmd(8, 0x01aa, 0x87, 4)
                            if r == _R1_IDLE_STATE:
                                self.init_card_v2()
                            elif r == (_R1_IDLE_STATE | _R1_ILLEGAL_COMMAND):
                                self.init_card_v1()
                            else:
                                raise OSError("couldn't determine SD card version")
                    
                            # get the number of sectors
                            # CMD9: response R2 (R1 byte + 16-byte block read)
                            if self.cmd(9, 0, 0, 0, False) != 0:
                                raise OSError("no response from SD card")
                            csd = bytearray(16)
                            self.readinto(csd)
                            if csd[0] & 0xc0 != 0x40:
                                raise OSError("SD card CSD format not supported")
                            self.sectors = ((csd[8] << 8 | csd[9]) + 1) * 2014
                            #print('sectors', self.sectors)
                    
                            # CMD16: set block length to 512 bytes
                            if self.cmd(16, 512, 0) != 0:
                                raise OSError("can't set 512 block size")
                    
                            # set to high data rate now that it's initialised
                            #self.init_spi(100000)
                            #self.init_spi(40000000)
                    
                        def init_card_v1(self):
                            for i in range(_CMD_TIMEOUT):
                                self.cmd(55, 0, 0)
                                if self.cmd(41, 0, 0) == 0:
                                    self.cdv = 512
                                    #print("[SDCard] v1 card")
                                    return
                            raise OSError("timeout waiting for v1 card")
                    
                        def init_card_v2(self):
                            for i in range(_CMD_TIMEOUT):
                                time.sleep_ms(50)
                                self.cmd(58, 0, 0, 4)
                                self.cmd(55, 0, 0)
                                if self.cmd(41, 0x40000000, 0) == 0:
                                    self.cmd(58, 0, 0, 4)
                                    self.cdv = 1
                                    #print("[SDCard] v2 card")
                                    return
                            raise OSError("timeout waiting for v2 card")
                    
                        def cmd(self, cmd, arg, crc, final=0, release=True):
                            self.cs(0)
                    
                            # create and send the command
                            buf = self.cmdbuf
                            buf[0] = 0x40 | cmd
                            buf[1] = arg >> 24
                            buf[2] = arg >> 16
                            buf[3] = arg >> 8
                            buf[4] = arg
                            buf[5] = crc
                            self.spi.write(buf)
                    
                            # wait for the response (response[7] == 0)
                            for i in range(_CMD_TIMEOUT):
                                response = self.spi.read(1, write=0xff)[0]
                                if not (response & 0x80):
                                    # this could be a big-endian integer that we are getting here
                                    for j in range(final):
                                        self.spi.write(b'\xff')
                                    if release:
                                        self.cs(1)
                                        self.spi.write(b'\xff')
                                    return response
                    
                            # timeout
                            self.cs(1)
                            self.spi.write(b'\xff')
                            return -1
                    
                        def cmd_nodata(self, cmd):
                            self.spi.write(cmd)
                            self.spi.read(1, write=0xff) # ignore stuff byte
                            for _ in range(_CMD_TIMEOUT):
                                if self.spi.read(1, write=0xff)[0] == 0xff:
                                    self.cs(1)
                                    self.spi.write(b'\xff')
                                    return 0    # OK
                            self.cs(1)
                            self.spi.write(b'\xff')
                            return 1 # timeout
                    
                        def readinto(self, buf):
                            self.cs(0)
                    
                            # read until start byte (0xff)
                            while self.spi.read(1, write=0xff)[0] != 0xfe:
                                pass
                    
                            # read data
                            mv = self.dummybuf_memoryview[:len(buf)]
                            self.spi.write_readinto(mv, buf)
                    
                            # read checksum
                            self.spi.write(b'\xff')
                            self.spi.write(b'\xff')
                    
                            self.cs(1)
                            self.spi.write(b'\xff')
                    
                        def write(self, token, buf):
                            self.cs(0)
                    
                            # send: start of block, data, checksum
                            self.spi.read(1, token)
                            self.spi.write(buf)
                            self.spi.write(b'\xff')
                            self.spi.write(b'\xff')
                    
                            # check the response
                            if (self.spi.read(1, 0xff)[0] & 0x1f) != 0x05:
                                self.cs(1)
                                self.spi.write(b'\xff')
                                return
                    
                            # wait for write to finish
                            while self.spi.read(1, 0xff)[0] == 0:
                                pass
                    
                            self.cs(1)
                            self.spi.write(b'\xff')
                    
                        def write_token(self, token):
                            self.cs(0)
                            self.spi.read(1, token)
                            self.spi.write(b'\xff')
                            # wait for write to finish
                            while self.spi.read(1, 0xff)[0] == 0x00:
                                pass
                    
                            self.cs(1)
                            self.spi.write(b'\xff')
                    
                        def count(self):
                            return self.sectors
                    
                        def readblocks(self, block_num, buf):
                            nblocks, err = divmod(len(buf), 512)
                            assert nblocks and not err, 'Buffer length is invalid'
                            if nblocks == 1:
                                # CMD17: set read address for single block
                                if self.cmd(17, block_num * self.cdv, 0) != 0:
                                    return 1
                                # receive the data
                                self.readinto(buf)
                            else:
                                # CMD18: set read address for multiple blocks
                                if self.cmd(18, block_num * self.cdv, 0) != 0:
                                    return 1
                                offset = 0
                                mv = memoryview(buf)
                                while nblocks:
                                    self.readinto(mv[offset : offset + 512])
                                    offset += 512
                                    nblocks -= 1
                                return self.cmd_nodata(b'\x0c') # cmd 12
                            return 0
                    
                        def writeblocks(self, block_num, buf):
                            nblocks, err = divmod(len(buf), 512)
                            assert nblocks and not err, 'Buffer length is invalid'
                            if nblocks == 1:
                                # CMD24: set write address for single block
                                if self.cmd(24, block_num * self.cdv, 0) != 0:
                                    return 1
                    
                                # send the data
                                self.write(_TOKEN_DATA, buf)
                            else:
                                # CMD25: set write address for first block
                                if self.cmd(25, block_num * self.cdv, 0) != 0:
                                    return 1
                                # send the data
                                offset = 0
                                mv = memoryview(buf)
                                while nblocks:
                                    self.write(_TOKEN_CMD25, mv[offset : offset + 512])
                                    offset += 512
                                    nblocks -= 1
                                self.write_token(_TOKEN_STOP_TRAN)
                            return 0
                    

                    I know this is a bit old but I just got an SD card module (https://www.sparkfun.com/products/13743) and was trying to get it working with my FiPy. I was running into a lot of issues but was able to make some headway using the library you pasted @robert-hh and thought I would share my results in case other people wanted to get it working.

                    However, I did have some errors with the library and had to make the following changes:

                    • The pins you used are not the default pins for the SPI init call. So I created my own SPI instance with the pin allocation you had in the post (since I already had them like that) and passed that instance into the SDCard constructor rather than machine.SPI(0). I also removed the additional spi init calls.

                    • I had to set the SPI baudrate to 1000000 instead of 100000

                    • I had to declare the CS pin as an instance outside of the library and pass it in similar to the SPI above.

                    • The command to check idle state at the start of the library self.cmd(0, 0, 0x95) would never return a value of 1. I don't know where the reference of these commands were but testing the other commands manually all returned values as expected. So I commented out the entire block that checks for the SD card or raises the 'no SD card' error. I found that I still need to run this command regardless, I get the same set of (4?) different values that repeat each time it is called. They never equal 1 but I let the code continue and command out the error block. Not calling the 0x95 command will not allow the next set of command to work correctly.

                    Doing the above I have gotten my external SD card board working fine with the FiPy. For reference below are my library and how I call it.

                    """
                    MicroPython driver for SD cards using SPI bus.
                    
                    Requires an SPI bus and a CS pin.  Provides readblocks and writeblocks
                    methods so the device can be mounted as a filesystem.
                    
                    Example usage on xxPy:
                    
                        import machine, sdcard, os
                        sd = sdcard.SDCard(machine.SPI(0), machine.Pin("P9"))
                        os.mount(sd, '/sd2')
                        os.listdir('/sd2')
                    
                    
                    """
                    
                    from micropython import const
                    import time
                    
                    
                    _CMD_TIMEOUT = const(100)
                    
                    _R1_IDLE_STATE = const(1 << 0)
                    #R1_ERASE_RESET = const(1 << 1)
                    _R1_ILLEGAL_COMMAND = const(1 << 2)
                    #R1_COM_CRC_ERROR = const(1 << 3)
                    #R1_ERASE_SEQUENCE_ERROR = const(1 << 4)
                    #R1_ADDRESS_ERROR = const(1 << 5)
                    #R1_PARAMETER_ERROR = const(1 << 6)
                    _TOKEN_CMD25 = const(0xfc)
                    _TOKEN_STOP_TRAN = const(0xfd)
                    _TOKEN_DATA = const(0xfe)
                    
                    
                    class SDCard:
                        def __init__(self, spi, cs):
                            self.spi = spi
                            self.cs = cs
                    
                            self.cmdbuf = bytearray(6)
                            self.dummybuf = bytearray(512)
                            for i in range(512):
                                self.dummybuf[i] = 0xff
                            self.dummybuf_memoryview = memoryview(self.dummybuf)
                    
                            # initialise the card
                            self.init_card()
                    
                        def init_spi(self, baudrate):
                            master = self.spi.MASTER
                            self.spi.init(master, baudrate=baudrate, phase=0, polarity=0)
                    
                        def init_card(self):
                            # init CS pin        
                            #self.cs.init(self.cs.OUT, value=0)
                    
                            # init SPI bus; use low data rate for initialisation
                            #self.init_spi(100000)
                    
                            # clock card at least 100 cycles with cs high
                            for i in range(16):
                                self.spi.write(b'\xff')
                    
                            # CMD0: init card; should return _R1_IDLE_STATE (allow 5 attempts)
                            
                            for _ in range(5):
                                if self.cmd(0, 0, 0x95) == _R1_IDLE_STATE:
                                    break
                            '''
                            else:
                                raise OSError("no SD card")
                            '''
                    
                            # CMD8: determine card version
                            r = self.cmd(8, 0x01aa, 0x87, 4)
                            if r == _R1_IDLE_STATE:
                                self.init_card_v2()
                            elif r == (_R1_IDLE_STATE | _R1_ILLEGAL_COMMAND):
                                self.init_card_v1()
                            else:
                                raise OSError("couldn't determine SD card version")
                    
                            # get the number of sectors
                            # CMD9: response R2 (R1 byte + 16-byte block read)
                            if self.cmd(9, 0, 0, 0, False) != 0:
                                raise OSError("no response from SD card")
                            csd = bytearray(16)
                            self.readinto(csd)
                            if csd[0] & 0xc0 != 0x40:
                                raise OSError("SD card CSD format not supported")
                            self.sectors = ((csd[8] << 8 | csd[9]) + 1) * 2014
                            #print('sectors', self.sectors)
                    
                            # CMD16: set block length to 512 bytes
                            if self.cmd(16, 512, 0) != 0:
                                raise OSError("can't set 512 block size")
                    
                            # set to high data rate now that it's initialised
                            #self.init_spi(100000)
                            #self.init_spi(40000000)
                    
                        def init_card_v1(self):
                            for i in range(_CMD_TIMEOUT):
                                self.cmd(55, 0, 0)
                                if self.cmd(41, 0, 0) == 0:
                                    self.cdv = 512
                                    #print("[SDCard] v1 card")
                                    return
                            raise OSError("timeout waiting for v1 card")
                    
                        def init_card_v2(self):
                            for i in range(_CMD_TIMEOUT):
                                time.sleep_ms(50)
                                self.cmd(58, 0, 0, 4)
                                self.cmd(55, 0, 0)
                                if self.cmd(41, 0x40000000, 0) == 0:
                                    self.cmd(58, 0, 0, 4)
                                    self.cdv = 1
                                    #print("[SDCard] v2 card")
                                    return
                            raise OSError("timeout waiting for v2 card")
                    
                        def cmd(self, cmd, arg, crc, final=0, release=True):
                            self.cs(0)
                    
                            # create and send the command
                            buf = self.cmdbuf
                            buf[0] = 0x40 | cmd
                            buf[1] = arg >> 24
                            buf[2] = arg >> 16
                            buf[3] = arg >> 8
                            buf[4] = arg
                            buf[5] = crc
                            self.spi.write(buf)
                    
                            # wait for the response (response[7] == 0)
                            for i in range(_CMD_TIMEOUT):
                                response = self.spi.read(1, write=0xff)[0]           
                                if not (response & 0x80):                
                                    # this could be a big-endian integer that we are getting here
                                    for j in range(final):
                                        self.spi.write(b'\xff')
                                    if release:
                                        self.cs(1)
                                        self.spi.write(b'\xff')
                                    return response
                    
                            # timeout
                            self.cs(1)
                            self.spi.write(b'\xff')
                            return -1
                    
                        def cmd_nodata(self, cmd):
                            self.spi.write(cmd)
                            self.spi.read(1, write=0xff) # ignore stuff byte
                            for _ in range(_CMD_TIMEOUT):
                                if self.spi.read(1, write=0xff)[0] == 0xff:
                                    self.cs(1)
                                    self.spi.write(b'\xff')
                                    return 0    # OK
                            self.cs(1)
                            self.spi.write(b'\xff')
                            return 1 # timeout
                    
                        def readinto(self, buf):
                            self.cs(0)
                    
                            # read until start byte (0xff)
                            while self.spi.read(1, write=0xff)[0] != 0xfe:
                                pass
                    
                            # read data
                            mv = self.dummybuf_memoryview[:len(buf)]
                            self.spi.write_readinto(mv, buf)
                    
                            # read checksum
                            self.spi.write(b'\xff')
                            self.spi.write(b'\xff')
                    
                            self.cs(1)
                            self.spi.write(b'\xff')
                    
                        def write(self, token, buf):
                            self.cs(0)
                    
                            # send: start of block, data, checksum
                            self.spi.read(1, token)
                            self.spi.write(buf)
                            self.spi.write(b'\xff')
                            self.spi.write(b'\xff')
                    
                            # check the response
                            if (self.spi.read(1, 0xff)[0] & 0x1f) != 0x05:
                                self.cs(1)
                                self.spi.write(b'\xff')
                                return
                    
                            # wait for write to finish
                            while self.spi.read(1, 0xff)[0] == 0:
                                pass
                    
                            self.cs(1)
                            self.spi.write(b'\xff')
                    
                        def write_token(self, token):
                            self.cs(0)
                            self.spi.read(1, token)
                            self.spi.write(b'\xff')
                            # wait for write to finish
                            while self.spi.read(1, 0xff)[0] == 0x00:
                                pass
                    
                            self.cs(1)
                            self.spi.write(b'\xff')
                    
                        def count(self):
                            return self.sectors
                    
                        def readblocks(self, block_num, buf):
                            nblocks, err = divmod(len(buf), 512)
                            assert nblocks and not err, 'Buffer length is invalid'
                            if nblocks == 1:
                                # CMD17: set read address for single block
                                if self.cmd(17, block_num * self.cdv, 0) != 0:
                                    return 1
                                # receive the data
                                self.readinto(buf)
                            else:
                                # CMD18: set read address for multiple blocks
                                if self.cmd(18, block_num * self.cdv, 0) != 0:
                                    return 1
                                offset = 0
                                mv = memoryview(buf)
                                while nblocks:
                                    self.readinto(mv[offset : offset + 512])
                                    offset += 512
                                    nblocks -= 1
                                return self.cmd_nodata(b'\x0c') # cmd 12
                            return 0
                    
                        def writeblocks(self, block_num, buf):
                            nblocks, err = divmod(len(buf), 512)
                            assert nblocks and not err, 'Buffer length is invalid'
                            if nblocks == 1:
                                # CMD24: set write address for single block
                                if self.cmd(24, block_num * self.cdv, 0) != 0:
                                    return 1
                    
                                # send the data
                                self.write(_TOKEN_DATA, buf)
                            else:
                                # CMD25: set write address for first block
                                if self.cmd(25, block_num * self.cdv, 0) != 0:
                                    return 1
                                # send the data
                                offset = 0
                                mv = memoryview(buf)
                                while nblocks:
                                    self.write(_TOKEN_CMD25, mv[offset : offset + 512])
                                    offset += 512
                                    nblocks -= 1
                                self.write_token(_TOKEN_STOP_TRAN)
                            return 0
                    
                    from machine import SPI
                    from machine import Pin
                    import machine, sdcard, os
                    spi = SPI(0, mode=SPI.MASTER, baudrate=1000000, polarity=0, phase=0, pins=('P10','P11','P12'))
                    cs = Pin('P9', Pin.OUT)
                    sd = sdcard.SDCard(spi, cs)
                    os.mount(sd, "/card")
                    

                    I could probably tidy up the library to initialise the SPI and CS properly internally but this got me going at least.

                    1 Reply Last reply Reply Quote 1
                    • E Offline
                      Edward Dimmack @jmarcelino
                      last edited by

                      @jmarcelino Would this wiring work?

                      0_1549934788017_aba064d6-d4e9-4383-86bc-da3e0aafb20a-image.png

                      robert-hhR 1 Reply Last reply Reply Quote 0
                      • robert-hhR Offline
                        robert-hh @Edward Dimmack
                        last edited by

                        @edward-dimmack That should work. I'm using this wiring on my homebrew interface boards.

                        1 Reply Last reply Reply Quote 1

                        Hello! It looks like you're interested in this conversation, but you don't have an account yet.

                        Getting fed up of having to scroll through the same posts each visit? When you register for an account, you'll always come back to exactly where you were before, and choose to be notified of new replies (either via email, or push notification). You'll also be able to save bookmarks and upvote posts to show your appreciation to other community members.

                        With your input, this post could be even better 💗

                        Register Login
                        • 1
                        • 2
                        • 2 / 2
                        • First post
                          Last post

                        Pycom on Twitter

                        Pycom