Need help to set the HW filters

[tetopik]

Hi, Viktor.
Thank you for making doing car reverse engineering a lot easier using esp32 devices.

I need help to set the hardware filters to accept only certain range of can IDs, in my case I only care for ID 0x18DAF100 through 0x18DAF1FF which only ignore the last 0xFF bytes.

So, tried to applied either one of this line and the result in unexpected:

can.set_filters(bank=0, mode=CAN.FILTER_RAW_SINGLE, params=[0x18DAF100, 0x1FFFFF00], rtr=False, extframe=True)
can.set_filters(bank=0, mode=CAN.FILTER_ADDRESS, params=[0x18DAF100, 0x1FFFFF00], rtr=False, extframe=True)

FILTER_RAW_SINGLE didn't catch anything while FILTER_ADDRESS catch only 0x18DAF100

[tetopik]

It turns out the id and mask in filter's params must be shifted all the way to the left to fill out all the 32 bit space:
11bit ID << 21 and 29bit ID << 3 .

But in mod_can.c:723 there is a bug for esp32_can_set_filters: // FIXME: Overflow in case 0xFFFFFFFF for mask.

So the solution I propose is to use this to avoids signed overflow/truncation:

// uint32_t id = mp_obj_get_int(params[0]);
// uint32_t mask = mp_obj_get_int(params[1]); // FIXME: Overflow in case 0xFFFFFFFF for mask
uint32_t id = (uint32_t)mp_obj_get_int_truncated(params[0]);
uint32_t mask = (uint32_t)mp_obj_get_int_truncated(params[1]);

I don't how to submit PR, so just pasted here just in case anyone face the same problem as mine.
Thanks.

[straga]

@tetopik Thanks. I do fix.