On Oct 21, 6:50 am, Brett <brettgra...@gmail.com> wrote: > I also posted this question to the linux-omap list and received some > helpful (and timely) assistance. I'm running this on an ARM (omap > 3530, gumstix). Here is the take-home message (from the omap technical > reference and reported to me > herehttp://www.spinics.net/lists/linux-omap/msg19347.html): > "CAUTION > The GP timer registers are limited to 32-bit and 16-bit data accesses; > 8-bit access is not allowed and can corrupt the register content." > > So... instead of calling mmap.read_byte() i'm calling mmap.read(4). > The thing I'm still wondering, is if python 'under-the-hood' is still > making 8-bit accesses. I thought it was fixed, but just got another > 'Unhandled fault'. Any hints?
Yes, read() operates by copying the value as a string, which means byte-by-byte access. (It's probably using a function such as PyString_FromStringAndLen under the convers.) I'm not sure you can even access the the memory through the mmap object except byte-by-byte. One way to get word access would be to use buffer protocol, which mmap supports, and create a numpy ndarray that references the mmap data. Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
