RPI Python Baca SPI
import time
import spidev
spi_ch = 0
# Enable SPI
spi = spidev.SpiDev(0, spi_ch)
spi.max_speed_hz = 1200000
def read_adc(adc_ch, vref = 3.3):
# Make sure ADC channel is 0 or 1
if adc_ch != 0:
adc_ch = 1
# Construct SPI message
# First bit (Start): Logic high (1)
# Second bit (SGL/DIFF): 1 to select single mode
# Third bit (ODD/SIGN): Select channel (0 or 1)
# Fourth bit (MSFB): 0 for LSB first
# Next 12 bits: 0 (don't care)
msg = 0b11
msg = ((msg << 1) + adc_ch) << 5
msg = [msg, 0b00000000]
reply = spi.xfer2(msg)
# Construct single integer out of the reply (2 bytes)
adc = 0
for n in reply:
adc = (adc << 8) + n
# Last bit (0) is not part of ADC value, shift to remove it
adc = adc >> 1
# Calculate voltage form ADC value
voltage = (vref * adc) / 1024
return voltage
# Report the channel 0 and channel 1 voltages to the terminal
try:
while True:
adc_0 = read_adc(0)
adc_1 = read_adc(1)
print("Ch 0:", round(adc_0, 2), "V Ch 1:", round(adc_1, 2), "V")
time.sleep(0.2)
finally:
spi.close()
GPIO.cleanup()
Ugly Unicorn