I had some issues with a USB bulk function on an STM32L1 controller (basically an echo for now) in that replied garbage. I could narrow it down to the USB peripheral wreaking havoc in my IN region of PMA. Given the datasheet [1, pp. 615/3018 - 616/3018, especially table 107], this happens due to NUM_BLOCK being one too large in the USBv1 implementation: For BL_SIZE=0 this field is 1-indexed while for BL_SIZE=1 it starts with 0 (Intuitive design, isn't it?
).With the following change I got rid of the problem:
os/hal/ports/STM32/LLD/USBv1/hal_usb_lld.c:643
nblocks = (((((epcp->out_maxsize - 1U) | 0x1FU) + 1U) / 32U) << 10) |
should read
nblocks = ((((epcp->out_maxsize - 1U) | 0x1FU) / 32U) << 10) |
,i.e., round down instead of up for packet sizes >62 bytes.
I'm pretty certain about this, however I wonder why nobody else stumbled across this issue. Anyway, here is the remaining information:
- ChibiOS version
21.11.1 (as of the tag ver21.11.1 on the github mirror)
- Compiler
gcc version 12.2.0 (Arch Repository)
newlib version 4.2.0.20211231-1
- Platform and board
STM32L151CBT6A on a custom board
- Nature of the problem / Failure Mode
Data is being corrupted in the PMA.
Cheers
Tim
[1] ST: Reference Manual RM0038. Revision 17: https://www.st.com/resource/en/referenc ... ronics.pdf
