Python • SPI Communication at Raspberry Pi Model 4 B Using Python

Code:

import spidev#import gpiodimport RPi.GPIO as GPIOimport timeCS_PIN = 8GPIO.setmode(GPIO.BCM)        # Use BCM numberingGPIO.setup(CS_PIN, GPIO.OUT)  # Set CS pin as outputGPIO.output(CS_PIN, GPIO.HIGH)  # Default to HIGH (inactive)# ===== SPI setup =====spi = spidev.SpiDev()spi.open(0, 0)                # /dev/spidev2.0spi.max_speed_hz = 500_000 # 10 MHzspi.mode = 0                  # SpiMode=1 from your WinCE code spi.bits_per_word = 8        # 16-bit words like PackedModespi.lsbfirst = False# ===== Data patterns =====# Each number here is a 16-bit wordspiData_1_MIC = [0xD414, 0x0001]spiData_2_MIC = [0xD414, 0x0001]spiData_3_MIC = [0xD414, 0x0001]spiData_4_MIC = [0xD414, 0x0001]def trigger_pulse():     GPIO.output(CS_PIN, GPIO.LOW)    time.sleep(0.00001)    GPIO.output(CS_PIN, GPIO.HIGH)    #time.sleep(0.000001)  # settledef spi_transfer(word_list):    # Convert 16-bit words to byte list    tx_bytes = []    for w in word_list:        tx_bytes.append((w >> 8) & 0xFF) # high byte        tx_bytes.append(w & 0xFF)        # low byte    rx_bytes = spi.xfer2(tx_bytes)    # Convert back to 16-bit words    rx_words = []    for i in range(0, len(rx_bytes), 2):        rx_words.append((rx_bytes[i+1] << 8) | rx_bytes[i])    return rx_wordsdef to_signed_16(val):    """Convert unsigned 16-bit to signed short."""    if val & 0x8000:  # if sign bit is set        val -= 0x10000    return valcounter = 0try:    while True:        #input("Press Enter to trigger probe and read SPI...")        # Exactly like WinCE loop:        trigger_pulse()        rx4 = spi_transfer(spiData_1_MIC)        rx3 = spi_transfer(spiData_2_MIC)        rx2 = spi_transfer(spiData_3_MIC)        rx1 = spi_transfer(spiData_4_MIC)        num_1_MIC = to_signed_16(rx1[0])        counter += 1        print(num_1_MIC,rx1,counter)        time.sleep(0.001)except KeyboardInterrupt:    passfinally:    trigger_line.set_value(0)    chip.close()    spi.close()