SPI0.write crashes Beagleblone

[jonturner53]

Running the following code causes the BeagleBone to crash when it gets
to the SPI0.write() call. To recover, I have to reset the board.
Am I doing something wrong here?

I am new to both the BeagleBone and PyBBIO, so I may be making a newbie error.
However, I have run a few tests involving the GPIOs and they all seem to work ok.
The blinking led example works fine, so I think the installation is ok.
I currently have no circuits connected to the board, so the tests using the GPIOs
are just wiggling pins (I have checked a few using a multi-meter, to make sure they're
responding).

Jon Turner

---

import sys
from bbio import *

def setup():
    SPI0.open()
    SPI0.setClockMode(0,0)  
    SPI0.setMaxFrequency(0,1000000) 
    SPI0.setBitsPerWord(0,10) 
    SPI0.setMSBFirst(0)

def loop() :
    print "about to write"
    SPI0.write(0,[0x15])
    print "done"
    sys.exit(0)

run(setup, loop)

[alexanderhiam]

See this issue on the serbus library (which PyBBIO uses): graycatlabs/serbus#1

It looks to be an bug in the omap2-mcspi kernel driver, so unfortunately nothing can really be done about it at the PyBBIO level. You could try using 12 or 16 bit words - in my experience SPI slave devices that use weird word sizes often just work with larger words.