esp-idf/components/hal/twai_hal.c

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// Copyright 2015-2019 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <stddef.h>
#include "hal/twai_hal.h"
//Default values written to various registers on initialization
#define TWAI_HAL_INIT_TEC 0
#define TWAI_HAL_INIT_REC 0
#define TWAI_HAL_INIT_EWL 96
/* ---------------------------- Init and Config ----------------------------- */
bool twai_hal_init(twai_hal_context_t *hal_ctx)
{
//Initialize HAL context
hal_ctx->dev = &TWAI;
hal_ctx->state_flags = 0;
//Initialize TWAI controller, and set default values to registers
twai_ll_enter_reset_mode(hal_ctx->dev);
if (!twai_ll_is_in_reset_mode(hal_ctx->dev)) { //Must enter reset mode to write to config registers
return false;
}
#if SOC_TWAI_SUPPORT_MULTI_ADDRESS_LAYOUT
twai_ll_enable_extended_reg_layout(hal_ctx->dev); //Changes the address layout of the registers
#endif
twai_ll_set_mode(hal_ctx->dev, TWAI_MODE_LISTEN_ONLY); //Freeze REC by changing to LOM mode
//Both TEC and REC should start at 0
twai_ll_set_tec(hal_ctx->dev, TWAI_HAL_INIT_TEC);
twai_ll_set_rec(hal_ctx->dev, TWAI_HAL_INIT_REC);
twai_ll_set_err_warn_lim(hal_ctx->dev, TWAI_HAL_INIT_EWL); //Set default value of for EWL
return true;
}
void twai_hal_deinit(twai_hal_context_t *hal_ctx)
{
//Clear any pending registers
(void) twai_ll_get_and_clear_intrs(hal_ctx->dev);
twai_ll_set_enabled_intrs(hal_ctx->dev, 0);
twai_ll_clear_arb_lost_cap(hal_ctx->dev);
twai_ll_clear_err_code_cap(hal_ctx->dev);
hal_ctx->dev = NULL;
}
void twai_hal_configure(twai_hal_context_t *hal_ctx, const twai_timing_config_t *t_config, const twai_filter_config_t *f_config, uint32_t intr_mask, uint32_t clkout_divider)
{
//Configure bus timing, acceptance filter, CLKOUT, and interrupts
twai_ll_set_bus_timing(hal_ctx->dev, t_config->brp, t_config->sjw, t_config->tseg_1, t_config->tseg_2, t_config->triple_sampling);
twai_ll_set_acc_filter(hal_ctx->dev, f_config->acceptance_code, f_config->acceptance_mask, f_config->single_filter);
twai_ll_set_clkout(hal_ctx->dev, clkout_divider);
twai_ll_set_enabled_intrs(hal_ctx->dev, intr_mask);
(void) twai_ll_get_and_clear_intrs(hal_ctx->dev); //Clear any latched interrupts
}
/* -------------------------------- Actions --------------------------------- */
void twai_hal_start(twai_hal_context_t *hal_ctx, twai_mode_t mode)
{
twai_ll_set_mode(hal_ctx->dev, mode); //Set operating mode
(void) twai_ll_get_and_clear_intrs(hal_ctx->dev); //Clear any latched interrupts
TWAI_HAL_SET_FLAG(hal_ctx->state_flags, TWAI_HAL_STATE_FLAG_RUNNING);
twai_ll_exit_reset_mode(hal_ctx->dev);
}
void twai_hal_stop(twai_hal_context_t *hal_ctx)
{
twai_ll_enter_reset_mode(hal_ctx->dev);
(void) twai_ll_get_and_clear_intrs(hal_ctx->dev);
twai_ll_set_mode(hal_ctx->dev, TWAI_MODE_LISTEN_ONLY); //Freeze REC by changing to LOM mode
//Any TX is immediately halted on entering reset mode
TWAI_HAL_RESET_FLAG(hal_ctx->state_flags, TWAI_HAL_STATE_FLAG_TX_BUFF_OCCUPIED);
TWAI_HAL_RESET_FLAG(hal_ctx->state_flags, TWAI_HAL_STATE_FLAG_RUNNING);
}