SPI + MS5540C driver

[BorbonJuggler]

Hello everyone,

I am trying to write the driver for the MS5540C Miniature Barometer Module using SPI interface, I based my code in an existing arduino sketch. Nevertheless, I haven't managed to read from the sensor, which worked on the Arduino Uno without problem. I think the problem is in the phase and polarity value that have to be change during the reading sequence, in the Arduino SPI they just change SPI.setDataMode(SPI_MODE1) to SPI.setDataMode(SPI_MODE0) . I am not familiar with the SPI protocol, so I post my code looking for any insight in this matter.

MS5540C.py:

import ustruct
import time
from machine import SPI, PWM

# SPI default pins for SCLK (CLK) , DIN(MOSI) and DOUT(MISO) (``P10``, ``P11`` and ``P14``)

# MCLK signal with a frequency of 32.768KHz on P12
pwm = PWM( 0, frequency=32768 )
# 0 create pwm channel on pin P12 with a duty cycle of 50%
pwm_c = pwm.channel ( 0, pin='P12', duty_cycle=0.5 )

_RESET_SEQUENCE = bytearray ( [0x15, 0x55, 0x40] )
_ADDRESS_WORD1 = bytearray ( [0x1D, 0x50] )
_ADDRESS_WORD2 = bytearray ( [0x1D, 0x60] )
_ADDRESS_WORD3 = bytearray ( [0x1D, 0x90] )
_ADDRESS_WORD4 = bytearray ( [0x1D, 0xA0] )

class MS5540C:

    def __init__( self ):

        #Calibration Word 1
        self.w1 = self.__read__calibration__word__( _ADDRESS_WORD1 )
        #Calibration Word 2
        self.w2 = self.__read__calibration__word__( _ADDRESS_WORD2 )
        #Calibration Word 3
        self.w3 = self.__read__calibration__word__( _ADDRESS_WORD3 )
        #Calibration Word 4
        self.w4 = self.__read__calibration__word__( _ADDRESS_WORD4 )

    def reset_sensor( self ):
        self.spi = SPI( 0, mode=SPI.MASTER, baudrate=500000, polarity=0, phase=0ze, firstbit=SPI.MSB )
        e = self.spi.write( _RESET_SEQUENCE ) # sent the byteds for _reset_sensor_
        if e != 3:
            print('Error en Reset \n')

    def __read__calibration__word__ ( self, adress ):
        self.reset_sensor() # phase = 0
        # Calibration word request
        e = self.spi.write( adress ) #  Get Calibration word
        if e != 2:
            print('Error en request Word \n')
        # Reading Calibration
        self.spi = SPI( 0, mode=SPI.MASTER, baudrate=500000, polarity=0, phase=1, firstbit=SPI.MSB )
        rbuf= self.spi.read(2)
        return  (rbuf[0] << 8) | rbuf[1]

main.py:

import time                   # Allows use of time.sleep() for delays
import pycom                  # Base library for Pycom devices
import ubinascii              # Needed to run any MicroPython code
import machine                # Interfaces with hardware components
import utime                  # Unix timestamp
import micropython            # Needed to run any MicroPython code
from machine import  Pin, Timer
from MS5540C import MS5540C



# Setup
# Level sensor
level_sensor = MS5540C()

# FUNCTIONS

# MAIN
def main():

    while True:
        print( "Word 1 is {}".format( level_sensor.w1 ) )
        print( "Word 2 is {}".format( level_sensor.w2 ) )
        print( "Word 3 is {}".format( level_sensor.w3 ) )
        print( "Word 4 is {}".format( level_sensor.w4 ) )
main()

[tttadam]

hello there,

Did you manage to solve this issue? :)
Thanks