I have run raspi-config and enabled SPI and also verified that /boot/config.txt contains the line:
dtparam=spi=on
However, when I run lsmod | grep spi I get the following:
spidev 16384 0
spi_bcm2835 16384 0
In /dev I can see: spidev0.0 and spidev0.1.
Is SPI enabled and functional? I have a feeling it's not working because my SunFounder LED screen, which relies on SPI, is not working.
I have been using raspi-config always found it working. Sometimes my modules are not working. So I usually use two little test programs to check. One program is to repeatedly send out bytes and use a scope to make sure the waveform looks OK. The other test program is a loop back test. I connect MOSI to MISO, send a byte and read back.
You might like to try my test program. It is plug and play, no libraries are required.
I have tested my program with IDLE python. To run in terminal mode:
Don't forget to run with sudo - otherwise the loopback test recvByte returns 0x0. – @glenneroo Apr 24 at 20:49
# spi_test05 tlfong01 2019apr07hkt2043 ***
# Computer = Rpi3B+
# Linux = $ hostnamectl = raspberrypi Raspbian GNU/Linux 9 (stretch) Linux 4.14.34-v7+ arm
# Python = >>> sys.version = 3.5.3 Jan 19 2017
# Test 1 - repeatSendByte() - SPI port repeatedly send out single bytes.
# Function - Repeat many times sending a byte, pause after each byte.
# Test 2 - loopBackTest() - SPI port send and receive one byte.
# Function - Send one byte to MSOI and read it back from MISO.
# Setup - Connet MOSI pin to MISO pin to form a loop.
from time import sleep
import spidev
spiPort0 = spidev.SpiDev()
spiPort0.open(0,0)
spiPort0.max_speed_hz = 100000
def spiSendRecvOneByte(spiPort, sendByte):
sendByteArray = [sendByte]
recvByteArray = spiPort.xfer(sendByteArray)
return recvByteArray
def repeatSendOneByte(spiPort, sendByte, pauseTimeBetweenBytes, repeatCount):
print('\nBegin repeatSendByte(),....')
for i in range(repeatCount):
spiSendRecvOneByte(spiPort, sendByte)
sleep(pauseTimeBetweenBytes)
print('End repeatSendByte().')
return
def loopBackOneByte(spiPort, sendByte):
recvByteArray = spiSendRecvOneByte(spiPort, sendByte)
recvByte = recvByteArray[0]
print('\nBegin testLoopbackOneByte(),....')
#print('')
print(' sendByte = ', hex(sendByte))
print(' recvByte = ', hex(recvByte))
#print('')
print('End testLoopbackOneByte(),....')
return
def testRepeatSendOneByte():
repeatSendOneByte(spiPort0, 0x5b, 0.0001, 20000000)
return
def testLoopbackOneByte():
loopBackOneByte(spiPort0, 0x5b)
return
testRepeatSendOneByte()
#testLoopbackOneByte()
''' Smple output tlfong 01 2019apr07hkt2047
Begin testLoopbackOneByte(),....
sendByte = 0x5b
recvByte = 0x5b
End testLoopbackOneByte(),....
'''
# *** End ***
Appendices
Appendix A - SPI Pinouts
SPI is working.
The needed modules are loaded (spidev, spi_bcm2835) and the needed devices are present (dev/spidev0.0 /dev/spidev0.1).
