Adafruit_BBIO SPI test: loopback test with SPI0 pins [/dev/spidev1]

adafruit_bbio_spi_test.md

Adafruit_BBIO SPI test

Loopback test with SPI0

• Connect wire from P9_18 [SPI0_D1] and P9_21 [SPI0_D0]
• Reference: P9 header pins

System Info

uname -r

4.4.39-ti-r79

/etc/debian_version

8.6

/etc/dogtag

BeagleBoard.org Debian Image 2016-11-27

/boot/uEnv.txt

uname_r=4.4.39-ti-r79
cmdline=coherent_pool=1M quiet cape_universal=enable

/sys/devices/platform/bone_capemgr/slots

 0: PF----  -1 
 1: PF----  -1 
 2: PF----  -1 
 3: PF----  -1 
 4: P-O-L-   0 Override Board Name,00A0,Override Manuf,cape-universaln

config-pin

config-pin P9_17 spi
config-pin P9_18 spi
config-pin P9_21 spi
config-pin P9_22 spi

test-spi.py

from Adafruit_BBIO.SPI import SPI

# From Adafruit Learning System:
# https://learn.adafruit.com/setting-up-io-python-library-on-beaglebone-black/spi     
#spi = SPI(bus, device) #/dev/spidev<bus>.<device>
#spi = SPI(0,0)	#/dev/spidev1.0
#spi = SPI(0,1)	#/dev/spidev1.1
#spi = SPI(1,0)	#/dev/spidev2.0
#spi = SPI(1,1)	#/dev/spidev2.1

spi = SPI(0,0) 
print spi.xfer2([32, 11, 110, 22, 220]) 
spi.close() 

output

debian@beaglebone:~/spi$ sudo python test-spi.py 
[32, 11, 110, 22, 220]

strace

debian@beaglebone:~/spi$ sudo strace -e open -f python ./test-spi.py 2>&1 |grep /dev/spidev
open("/dev/spidev1.0", O_RDWR|O_LARGEFILE) = 3