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stm32/can: Add CAN.restart() method so controller can leave bus-off.

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This commit is contained in:
Damien George 2018-03-15 17:29:30 +11:00
parent 823ca03008
commit 1272c3c65d
2 changed files with 31 additions and 1 deletions
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14
docs/library/pyb.CAN.rst
View File

@ -65,7 +65,8 @@ Methods
- *bs2* defines the location of the transmit point in units of the time quanta;
it can be between 1 and 16 inclusive
- *auto_restart* sets whether the controller will automatically try and restart
communications after entering the bus-off state
communications after entering the bus-off state; if this is disabled then
:meth:`~CAN.restart()` can be used to leave the bus-off state
The time quanta tq is the basic unit of time for the CAN bus. tq is the CAN
prescaler value divided by PCLK1 (the frequency of internal peripheral bus 1);
@ -87,6 +88,17 @@ Methods
Turn off the CAN bus.
.. method:: CAN.restart()
Force a software restart of the CAN controller without resetting its
configuration.
If the controller enters the bus-off state then it will no longer participate
in bus activity. If the controller is not configured to automatically restart
(see :meth:`~CAN.init()`) then this method can be used to trigger a restart,
and the controller will follow the CAN protocol to leave the bus-off state and
go into the error active state.
.. method:: CAN.setfilter(bank, mode, fifo, params, \*, rtr)
Configure a filter bank:

18
ports/stm32/can.c
View File

@ -467,6 +467,23 @@ STATIC mp_obj_t pyb_can_deinit(mp_obj_t self_in) {
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_can_deinit_obj, pyb_can_deinit);
// Force a software restart of the controller, to allow transmission after a bus error
STATIC mp_obj_t pyb_can_restart(mp_obj_t self_in) {
pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
if (!self->is_enabled) {
mp_raise_ValueError(NULL);
}
CAN_TypeDef *can = self->can.Instance;
can->MCR |= CAN_MCR_INRQ;
while ((can->MSR & CAN_MSR_INAK) == 0) {
}
can->MCR &= ~CAN_MCR_INRQ;
while ((can->MSR & CAN_MSR_INAK)) {
}
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_can_restart_obj, pyb_can_restart);
/// \method any(fifo)
/// Return `True` if any message waiting on the FIFO, else `False`.
STATIC mp_obj_t pyb_can_any(mp_obj_t self_in, mp_obj_t fifo_in) {
@ -824,6 +841,7 @@ STATIC const mp_rom_map_elem_t pyb_can_locals_dict_table[] = {
// instance methods
{ MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&pyb_can_init_obj) },
{ MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&pyb_can_deinit_obj) },
{ MP_ROM_QSTR(MP_QSTR_restart), MP_ROM_PTR(&pyb_can_restart_obj) },
{ MP_ROM_QSTR(MP_QSTR_any), MP_ROM_PTR(&pyb_can_any_obj) },
{ MP_ROM_QSTR(MP_QSTR_send), MP_ROM_PTR(&pyb_can_send_obj) },
{ MP_ROM_QSTR(MP_QSTR_recv), MP_ROM_PTR(&pyb_can_recv_obj) },