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Damien George authoredAlso update docs to explain how CAN baudrate is determined.
Damien George authoredAlso update docs to explain how CAN baudrate is determined.
can.c 16.08 KiB
/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2014 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <errno.h>
#include "mpconfig.h"
#include "nlr.h"
#include "misc.h"
#include "qstr.h"
#include "obj.h"
#include "objtuple.h"
#include "runtime.h"
#include "bufhelper.h"
#include "can.h"
#include "pybioctl.h"
#include MICROPY_HAL_H
#if MICROPY_HW_ENABLE_CAN
/// \moduleref pyb
/// \class CAN - controller area network communication bus
///
/// CAN implements the standard CAN communications protocol. At
/// the physical level it consists of 2 lines: RX and TX. Note that
/// to connect the pyboard to a CAN bus you must use a CAN transceiver
/// to convert the CAN logic signals from the pyboard to the correct
/// voltage levels on the bus.
///
/// Note that this driver does not yet support filter configuration
/// (it defaults to a single filter that lets through all messages),
/// or bus timing configuration (except for setting the prescaler).
///
/// Example usage (works without anything connected):
///
/// from pyb import CAN
/// can = pyb.CAN(1, pyb.CAN.LOOPBACK)
/// can.send('message!', 123) # send message with id 123
/// can.recv(0) # receive message on FIFO 0
typedef struct _pyb_can_obj_t {
mp_obj_base_t base;
mp_uint_t can_id : 8;
bool is_enabled : 1;
bool extframe : 1; CAN_HandleTypeDef can;
} pyb_can_obj_t;
// assumes Init parameters have been set up correctly
STATIC bool can_init(pyb_can_obj_t *can_obj) {
CAN_TypeDef *CANx = NULL;
uint32_t GPIO_Pin = 0;
uint8_t GPIO_AF_CANx = 0;
GPIO_TypeDef* GPIO_Port = NULL;
switch (can_obj->can_id) {
// CAN1 is on RX,TX = Y3,Y4 = PB9,PB9
case PYB_CAN_1:
CANx = CAN1;
GPIO_AF_CANx = GPIO_AF9_CAN1;
GPIO_Port = GPIOB;
GPIO_Pin = GPIO_PIN_8 | GPIO_PIN_9;
__CAN1_CLK_ENABLE();
break;
// CAN2 is on RX,TX = Y5,Y6 = PB12,PB13
case PYB_CAN_2:
CANx = CAN2;
GPIO_AF_CANx = GPIO_AF9_CAN2;
GPIO_Port = GPIOB;
GPIO_Pin = GPIO_PIN_12 | GPIO_PIN_13;
__CAN1_CLK_ENABLE(); // CAN2 is a "slave" and needs CAN1 enabled as well
__CAN2_CLK_ENABLE();
break;
default:
return false;
}
// init GPIO
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.Pin = GPIO_Pin;
GPIO_InitStructure.Speed = GPIO_SPEED_HIGH;
GPIO_InitStructure.Mode = GPIO_MODE_AF_PP;
GPIO_InitStructure.Pull = GPIO_PULLUP;
GPIO_InitStructure.Alternate = GPIO_AF_CANx;
HAL_GPIO_Init(GPIO_Port, &GPIO_InitStructure);
// init CANx
can_obj->can.Instance = CANx;
HAL_CAN_Init(&can_obj->can);
can_obj->is_enabled = true;
return true;
}
STATIC void can_deinit(pyb_can_obj_t *can_obj) {
can_obj->is_enabled = false;
CAN_HandleTypeDef *can = &can_obj->can;
HAL_CAN_DeInit(can);
if (can->Instance == CAN1) {
__CAN1_FORCE_RESET();
__CAN1_RELEASE_RESET();
__CAN1_CLK_DISABLE();
} else if (can->Instance == CAN2) {
__CAN2_FORCE_RESET();
__CAN2_RELEASE_RESET();
__CAN2_CLK_DISABLE();
}
}
/******************************************************************************/
// Micro Python bindings
STATIC void pyb_can_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
pyb_can_obj_t *self = self_in;
if (!self->is_enabled) {
print(env, "CAN(%u)", self->can_id);
} else {
print(env, "CAN(%u, CAN.", self->can_id);
qstr mode;
switch (self->can.Init.Mode) {
case CAN_MODE_NORMAL: mode = MP_QSTR_NORMAL; break;
case CAN_MODE_LOOPBACK: mode = MP_QSTR_LOOPBACK; break;
case CAN_MODE_SILENT: mode = MP_QSTR_SILENT; break;
case CAN_MODE_SILENT_LOOPBACK: default: mode = MP_QSTR_SILENT_LOOPBACK; break;
}
print(env, "%s, extframe=", qstr_str(mode));
if (self->extframe) {
mode = MP_QSTR_True;
} else {
mode = MP_QSTR_False;
}
print(env, "%s)", qstr_str(mode));
}
}
// init(mode, extframe=False, prescaler=100, *, sjw=1, bs1=6, bs2=8)
STATIC mp_obj_t pyb_can_init_helper(pyb_can_obj_t *self, mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_mode, MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = CAN_MODE_NORMAL} },
{ MP_QSTR_extframe, MP_ARG_BOOL, {.u_bool = false} },
{ MP_QSTR_prescaler, MP_ARG_INT, {.u_int = 100} },
{ MP_QSTR_sjw, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 1} },
{ MP_QSTR_bs1, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 6} },
{ MP_QSTR_bs2, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 8} },
};
// parse args
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
self->extframe = args[1].u_bool;
// set the CAN configuration values
memset(&self->can, 0, sizeof(self->can));
CAN_InitTypeDef *init = &self->can.Init;
init->Mode = args[0].u_int << 4; // shift-left so modes fit in a small-int
init->Prescaler = args[2].u_int;
init->SJW = ((args[3].u_int - 1) & 3) << 24;
init->BS1 = ((args[4].u_int - 1) & 0xf) << 16;
init->BS2 = ((args[5].u_int - 1) & 7) << 20;
init->TTCM = DISABLE;
init->ABOM = DISABLE;
init->AWUM = DISABLE;
init->NART = DISABLE;
init->RFLM = DISABLE;
init->TXFP = DISABLE;
// init CAN (if it fails, it's because the port doesn't exist)
if (!can_init(self)) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "CAN port %d does not exist", self->can_id));
}
// set CAN filter to accept everything
CAN_FilterConfTypeDef filter;
filter.FilterIdHigh = 0;
filter.FilterIdLow = 0;
filter.FilterMaskIdHigh = 0;
filter.FilterMaskIdLow = 0;
filter.FilterFIFOAssignment = CAN_FILTER_FIFO0;
filter.FilterNumber = 0; // 0-27
filter.FilterMode = CAN_FILTERMODE_IDMASK; filter.FilterScale = CAN_FILTERSCALE_32BIT;
filter.FilterActivation = ENABLE;
filter.BankNumber = 0; // what's this for?
HAL_CAN_ConfigFilter(&self->can, &filter);
return mp_const_none;
}
/// \classmethod \constructor(bus, ...)
///
/// Construct a CAN object on the given bus. `bus` can be 1-2, or 'YA' or 'YB'.
/// With no additional parameters, the CAN object is created but not
/// initialised (it has the settings from the last initialisation of
/// the bus, if any). If extra arguments are given, the bus is initialised.
/// See `init` for parameters of initialisation.
///
/// The physical pins of the CAN busses are:
///
/// - `CAN(1)` is on `YA`: `(RX, TX) = (Y3, Y4) = (PB8, PB9)`
/// - `CAN(2)` is on `YB`: `(RX, TX) = (Y5, Y6) = (PB12, PB13)`
STATIC mp_obj_t pyb_can_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
// check arguments
mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
// create object
pyb_can_obj_t *o = m_new_obj(pyb_can_obj_t);
o->base.type = &pyb_can_type;
o->is_enabled = false;
// work out port
o->can_id = 0;
if (MP_OBJ_IS_STR(args[0])) {
const char *port = mp_obj_str_get_str(args[0]);
if (0) {
#if defined(PYBV10)
} else if (strcmp(port, "YA") == 0) {
o->can_id = PYB_CAN_YA;
} else if (strcmp(port, "YB") == 0) {
o->can_id = PYB_CAN_YB;
#endif
} else {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "CAN port %s does not exist", port));
}
} else {
o->can_id = mp_obj_get_int(args[0]);
}
if (n_args > 1 || n_kw > 0) {
// start the peripheral
mp_map_t kw_args;
mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
pyb_can_init_helper(o, n_args - 1, args + 1, &kw_args);
}
return o;
}
STATIC mp_obj_t pyb_can_init(mp_uint_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
return pyb_can_init_helper(args[0], n_args - 1, args + 1, kw_args);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_can_init_obj, 1, pyb_can_init);
/// \method deinit()
/// Turn off the CAN bus.
STATIC mp_obj_t pyb_can_deinit(mp_obj_t self_in) {
pyb_can_obj_t *self = self_in;
can_deinit(self);
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_can_deinit_obj, pyb_can_deinit);
/// \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) {
pyb_can_obj_t *self = self_in;
mp_int_t fifo = mp_obj_get_int(fifo_in);
if (fifo == 0) {
if (__HAL_CAN_MSG_PENDING(&self->can, CAN_FIFO0) != 0) {
return mp_const_true;
}
} else {
if (__HAL_CAN_MSG_PENDING(&self->can, CAN_FIFO1) != 0) {
return mp_const_true;
}
}
return mp_const_false;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_can_any_obj, pyb_can_any);
/// \method send(send, addr, *, timeout=5000)
/// Send a message on the bus:
///
/// - `send` is the data to send (an integer to send, or a buffer object).
/// - `addr` is the address to send to
/// - `timeout` is the timeout in milliseconds to wait for the send.
///
/// Return value: `None`.
STATIC mp_obj_t pyb_can_send(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_send, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_addr, MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 5000} },
};
// parse args
pyb_can_obj_t *self = pos_args[0];
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
// get the buffer to send from
mp_buffer_info_t bufinfo;
uint8_t data[1];
pyb_buf_get_for_send(args[0].u_obj, &bufinfo, data);
if (bufinfo.len > 8) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "CAN data field too long"));
}
// send the data
CanTxMsgTypeDef tx_msg;
if (self->extframe){
tx_msg.ExtId = args[1].u_int & 0x1FFFFFFF;
tx_msg.IDE = CAN_ID_EXT;
} else {
tx_msg.StdId = args[1].u_int & 0x7FF;
tx_msg.IDE = CAN_ID_STD;
}
tx_msg.RTR = CAN_RTR_DATA;
tx_msg.DLC = bufinfo.len;
for (mp_uint_t i = 0; i < bufinfo.len; i++) {
tx_msg.Data[i] = ((byte*)bufinfo.buf)[i]; // Data is uint32_t but holds only 1 byte
}
self->can.pTxMsg = &tx_msg;
HAL_StatusTypeDef status = HAL_CAN_Transmit(&self->can, args[2].u_int);
if (status != HAL_OK) {
mp_hal_raise(status);
}
return mp_const_none;}
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_can_send_obj, 1, pyb_can_send);
/// \method recv(fifo, *, timeout=5000)
///
/// Receive data on the bus:
///
/// - `fifo` is an integer, which is the FIFO to receive on
/// - `timeout` is the timeout in milliseconds to wait for the receive.
///
/// Return value: buffer of data bytes.
STATIC mp_obj_t pyb_can_recv(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_fifo, MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 5000} },
};
// parse args
pyb_can_obj_t *self = pos_args[0];
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
// receive the data
CanRxMsgTypeDef rx_msg;
self->can.pRxMsg = &rx_msg;
HAL_StatusTypeDef status = HAL_CAN_Receive(&self->can, args[0].u_int, args[1].u_int);
if (status != HAL_OK) {
mp_hal_raise(status);
}
// return the received data
// TODO use a namedtuple (when namedtuple types can be stored in ROM)
mp_obj_tuple_t *tuple = mp_obj_new_tuple(4, NULL);
if (rx_msg.IDE == CAN_ID_STD) {
tuple->items[0] = MP_OBJ_NEW_SMALL_INT(rx_msg.StdId);
} else {
tuple->items[0] = MP_OBJ_NEW_SMALL_INT(rx_msg.ExtId);
}
tuple->items[1] = MP_OBJ_NEW_SMALL_INT(rx_msg.RTR);
tuple->items[2] = MP_OBJ_NEW_SMALL_INT(rx_msg.FMI);
byte *data;
tuple->items[3] = mp_obj_str_builder_start(&mp_type_bytes, rx_msg.DLC, &data);
for (mp_uint_t i = 0; i < rx_msg.DLC; i++) {
data[i] = rx_msg.Data[i]; // Data is uint32_t but holds only 1 byte
}
tuple->items[3] = mp_obj_str_builder_end(tuple->items[3]);
return tuple;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_can_recv_obj, 1, pyb_can_recv);
STATIC const mp_map_elem_t pyb_can_locals_dict_table[] = {
// instance methods
{ MP_OBJ_NEW_QSTR(MP_QSTR_init), (mp_obj_t)&pyb_can_init_obj },
{ MP_OBJ_NEW_QSTR(MP_QSTR_deinit), (mp_obj_t)&pyb_can_deinit_obj },
{ MP_OBJ_NEW_QSTR(MP_QSTR_any), (mp_obj_t)&pyb_can_any_obj },
{ MP_OBJ_NEW_QSTR(MP_QSTR_send), (mp_obj_t)&pyb_can_send_obj },
{ MP_OBJ_NEW_QSTR(MP_QSTR_recv), (mp_obj_t)&pyb_can_recv_obj },
// class constants
// Note: we use the ST constants >> 4 so they fit in a small-int. The
// right-shift is undone when the constants are used in the init function.
{ MP_OBJ_NEW_QSTR(MP_QSTR_NORMAL), MP_OBJ_NEW_SMALL_INT(CAN_MODE_NORMAL >> 4) },
{ MP_OBJ_NEW_QSTR(MP_QSTR_LOOPBACK), MP_OBJ_NEW_SMALL_INT(CAN_MODE_LOOPBACK >> 4) },
{ MP_OBJ_NEW_QSTR(MP_QSTR_SILENT), MP_OBJ_NEW_SMALL_INT(CAN_MODE_SILENT >> 4) },
{ MP_OBJ_NEW_QSTR(MP_QSTR_SILENT_LOOPBACK), MP_OBJ_NEW_SMALL_INT(CAN_MODE_SILENT_LOOPBACK >> 4) },
};
STATIC MP_DEFINE_CONST_DICT(pyb_can_locals_dict, pyb_can_locals_dict_table);
mp_uint_t can_ioctl(mp_obj_t self_in, mp_uint_t request, int *errcode, ...) {
pyb_can_obj_t *self = self_in;
va_list vargs;
va_start(vargs, errcode);
mp_uint_t ret;
if (request == MP_IOCTL_POLL) {
mp_uint_t flags = va_arg(vargs, mp_uint_t);
ret = 0;
if ((flags & MP_IOCTL_POLL_RD)
&& ((__HAL_CAN_MSG_PENDING(&self->can, CAN_FIFO0) != 0)
|| (__HAL_CAN_MSG_PENDING(&self->can, CAN_FIFO1) != 0))) {
ret |= MP_IOCTL_POLL_RD;
}
if ((flags & MP_IOCTL_POLL_WR) && (self->can.Instance->TSR & CAN_TSR_TME)) {
ret |= MP_IOCTL_POLL_WR;
}
} else {
*errcode = EINVAL;
ret = -1;
}
va_end(vargs);
return ret;
}
STATIC const mp_stream_p_t can_stream_p = {
//.read = can_read, // is read sensible for CAN?
//.write = can_write, // is write sensible for CAN?
.ioctl = can_ioctl,
.is_text = false,
};
const mp_obj_type_t pyb_can_type = {
{ &mp_type_type },
.name = MP_QSTR_CAN,
.print = pyb_can_print,
.make_new = pyb_can_make_new,
.stream_p = &can_stream_p,
.locals_dict = (mp_obj_t)&pyb_can_locals_dict,
};
#endif // MICROPY_HW_ENABLE_CAN