UART

[loics]

Hello,
I have trouble understanding UART communication on the FiPy.

I use a FiPy 1.0, and Pysense but only for Vin, GND, TX0 and RX0 (simpler for me), the rest is done on a breadboard.

Using ATOM text editor, and the following test code :

uart = UART(1)
uart.init(9600, bits=8, parity=None, stop=1, pins=('P3','P4')) 

compteur = 0

while True:
    pycom.rgbled(0x001000)

    uart.write("\x30\x31\x32\x33")
    time.sleep_ms(100)

    input = uart.read()

    if input is not None:
        compteur += 1
        print("INPUT : " + str(compteur))
        print(input)

    pycom.rgbled(0x000000)
    time.sleep_ms(1000)

If I connect P3 and P4 with a jumper, I get :

INPUT : 1
b'0123'
INPUT : 2
b'0123'
INPUT : 3
b'0123'
...

in the ATOM editor log (as expected).

However, when I try to read the output with a USB->RS232 converter, my COM debuging software (Docklight) receives (in hex)

D6 B6 96 06

And the FiPy reads a giant byte string composed of hundreds (600-700) of '\x00', even though nothing is sent.

If I switch RX/TX then nothing happends, so that is not the issue. The FiPy is up to date.

Do you have any ideas or recommandations for further testing ?

PS : I can use this USB->RS232 converter and Docklight to succesfully chat with other devices such as industrial tiltmeters.

[crumble]

You are naming it wrong.

Have a look on the syntax highlighting of input. It is marked red, because input() is an internal function. Rename your variable to something safe like my_input and try it again.

[loics]

Thanks for noticing that, ATOM does not highlight "input" as a keyword...

However, renaming dit not change the result.

[loics]

So in the first post, I was trying reading data sent by the Pycom.
I tried today to read data sent to the Pycom with the following code :

uart=UART(1, 115200, bits=8, parity=None, stop=1, pins=('P3','P4'))

while True:
    if(uart.any()>0):
        compteur += 1
        print("INPUT : " + str(compteur) + " (" + str(uart.any()) + ")")
        buf=uart.read()
        print(buf)

I have a sensor wich sends an ASCII string (18 bytes long) every second. I can read it with an USB->RS232 converter. However, On the pycom, I get the following "gibberish", every 4-5 seconds :

INPUT : 9 (120)
b'\x06\x06\xb4\x06d3yj\x06\x06\x06\xb4\x06\x0c\x19Z\r\x06\x06\x06\xb4\x06d3yj\x06\x06\x06\xb4\x06\x0c2Z\r\x06\x06\x06\xb4\x06dgyj\x06\x06\x06\xb4\x06\x0c\x19Z\r\x06\x06\x06\xb4\x06d3yj\x06\x06\x06\xb4\x06\x0c2Z\r\x06\x06\x06\xb4\x06d3yj\x06\x06\x06\xb4\x06\x0ceZ\r\x06\x06\x06\xb4\x06d\x19yj\x06\x06\x06\xb4\x06\x0c2Z\r\x06\x06\x06\xb4\x06d\x19yj\x06\x06\x06\xb4'
INPUT : 10 (120)
b'\x06\x0ceZ\r\x06\x06\x06\xb4\x06d\x19yj\x06\x06\x06\xb4\x06\x0ceZ\r\x06\x06\x06\xb4\x06d\x19yj\x06\x06\x06\xb4\x06\x0c2Z\r\x06\x06\x06\xb4\x06dfyj\x06\x06\x06\xb4\x06\x0c2Z\r\x06\x06\x06\xb4\x06d\x19yj\x06\x06\x06\xb4\x06\x0ceZ\r\x06\x06\x06\xb4\x06deyj\x06\x06\x06\xb4\x06\x0cfZ\r\x06\x06\x06\xb4\x06d2yj\x06\x06\x06\xb4\x06\x0c\x19Z\r\x06\x06\x06\xb4\x06de'

The COM parameters are correct (115200, 8, None, 1). I connected the COM GND of my sensor to the GND of the Pycom.

Does anyone has had a similar issue ? I can't find anything on the forum.

[loics]

Solved : turns out I needed a USB<->TTL and not an USB<->RS232...

I did not know about the TTL standard, as I did not study eletronics at all. Gotta learn the hard way !