djsundog/circuitpython
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

stm32: canio: When Tx mailboxes are full, cancel an old message

Browse Source 
.. also add the 8ms wait for transmission that the atmel sam port
has
This commit is contained in:
Jeff Epler 2020-10-06 09:18:53 -05:00
parent a7dccb39a4
commit e5a0af9216
2 changed files with 19 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
ports/stm/common-hal/canio/CAN.c
View File

@ -225,10 +225,28 @@ void common_hal_canio_can_send(canio_can_obj_t *self, mp_obj_t message_in)
.RTR = rtr ? CAN_RTR_REMOTE : CAN_RTR_DATA,
.DLC = message->size,
};
uint32_t free_level = HAL_CAN_GetTxMailboxesFreeLevel(&self->handle);
if (free_level == 0) {
// There's no free Tx mailbox. We need to cancel some message without
// transmitting it, because once the bus returns to active state it's
// preferable to transmit the newest messages instead of older messages.
//
// We don't strictly guarantee that we abort the oldest Tx request,
// rather we just abort a different index each time. This permits us
// to avoid tracking this information altogether.
HAL_CAN_AbortTxRequest(&self->handle, 1 << (self->cancel_mailbox));
self->cancel_mailbox = (self->cancel_mailbox + 1) % 3;
}
HAL_StatusTypeDef status = HAL_CAN_AddTxMessage(&self->handle, &header, message->data, &mailbox);
if (status != HAL_OK) {
mp_raise_OSError(MP_ENOMEM);
}
// wait 8ms (hard coded for now) for TX to occur
uint64_t deadline = port_get_raw_ticks(NULL) + 8;
while (port_get_raw_ticks(NULL) < deadline && HAL_CAN_IsTxMessagePending(&self->handle, 1 << mailbox)) {
RUN_BACKGROUND_TASKS;
}
}
bool common_hal_canio_can_silent_get(canio_can_obj_t *self) {

1
ports/stm/common-hal/canio/CAN.h
View File

@ -54,6 +54,7 @@ typedef struct canio_can_obj {
bool fifo0_in_use:1;
bool fifo1_in_use:1;
uint8_t periph_index:2;
uint8_t cancel_mailbox;
uint8_t start_filter_bank;
uint8_t end_filter_bank;
long filter_in_use; // bitmask for the 28 filter banks