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OVMS3-idf/components/soc/src/esp32s2/include/hal/twai_ll.h
Darian Leung e6db25af9d TWAI: Add ESP32-S2 support 
This commit adds TWAI driver support for the
ESP32-S2. The following features were added:

- Expanded BRP support
- Expanded CLKOUT Divider Support
- Updated example READMEs
2020-07-30 22:09:39 +08:00

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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.
/*******************************************************************************
* NOTICE
* The ll is not public api, don't use in application code.
* See readme.md in soc/include/hal/readme.md
******************************************************************************/
// The Lowlevel layer for TWAI
#pragma once
#ifdef __cplusplus
extern "C" {
#endif
#include <stdint.h>
#include <stdbool.h>
#include "hal/twai_types.h"
#include "soc/twai_periph.h"
/* ------------------------- Defines and Typedefs --------------------------- */
#define TWAI_LL_STATUS_RBS (0x1 << 0)
#define TWAI_LL_STATUS_DOS (0x1 << 1)
#define TWAI_LL_STATUS_TBS (0x1 << 2)
#define TWAI_LL_STATUS_TCS (0x1 << 3)
#define TWAI_LL_STATUS_RS (0x1 << 4)
#define TWAI_LL_STATUS_TS (0x1 << 5)
#define TWAI_LL_STATUS_ES (0x1 << 6)
#define TWAI_LL_STATUS_BS (0x1 << 7)
//Todo: Add Miss status support
#define TWAI_LL_INTR_RI (0x1 << 0)
#define TWAI_LL_INTR_TI (0x1 << 1)
#define TWAI_LL_INTR_EI (0x1 << 2)
//Data overrun interrupt not supported in SW due to HW peculiarities
#define TWAI_LL_INTR_EPI (0x1 << 5)
#define TWAI_LL_INTR_ALI (0x1 << 6)
#define TWAI_LL_INTR_BEI (0x1 << 7)
/*
* The following frame structure has an NEARLY identical bit field layout to
* each byte of the TX buffer. This allows for formatting and parsing frames to
* be done outside of time critical regions (i.e., ISRs). All the ISR needs to
* do is to copy byte by byte to/from the TX/RX buffer. The two reserved bits in
* TX buffer are used in the frame structure to store the self_reception and
* single_shot flags which in turn indicate the type of transmission to execute.
*/
typedef union {
struct {
struct {
uint8_t dlc: 4; //Data length code (0 to 8) of the frame
uint8_t self_reception: 1; //This frame should be transmitted using self reception command
uint8_t single_shot: 1; //This frame should be transmitted using single shot command
uint8_t rtr: 1; //This frame is a remote transmission request
uint8_t frame_format: 1; //Format of the frame (1 = extended, 0 = standard)
};
union {
struct {
uint8_t id[2]; //11 bit standard frame identifier
uint8_t data[8]; //Data bytes (0 to 8)
uint8_t reserved8[2];
} standard;
struct {
uint8_t id[4]; //29 bit extended frame identifier
uint8_t data[8]; //Data bytes (0 to 8)
} extended;
};
};
uint8_t bytes[13];
} __attribute__((packed)) twai_ll_frame_buffer_t;
_Static_assert(sizeof(twai_ll_frame_buffer_t) == 13, "TX/RX buffer type should be 13 bytes");
/* ---------------------------- Mode Register ------------------------------- */
/**
* @brief Enter reset mode
*
* When in reset mode, the TWAI controller is effectively disconnected from the
* TWAI bus and will not participate in any bus activates. Reset mode is required
* in order to write the majority of configuration registers.
*
* @param hw Start address of the TWAI registers
* @return true if reset mode was entered successfully
*
* @note Reset mode is automatically entered on BUS OFF condition
*/
static inline bool twai_ll_enter_reset_mode(twai_dev_t *hw)
{
hw->mode_reg.rm = 1;
return hw->mode_reg.rm;
}
/**
* @brief Exit reset mode
*
* When not in reset mode, the TWAI controller will take part in bus activities
* (e.g., send/receive/acknowledge messages and error frames) depending on the
* operating mode.
*
* @param hw Start address of the TWAI registers
* @return true if reset mode was exit successfully
*
* @note Reset mode must be exit to initiate BUS OFF recovery
*/
static inline bool twai_ll_exit_reset_mode(twai_dev_t *hw)
{
hw->mode_reg.rm = 0;
return !(hw->mode_reg.rm);
}
/**
* @brief Check if in reset mode
* @param hw Start address of the TWAI registers
* @return true if in reset mode
*/
static inline bool twai_ll_is_in_reset_mode(twai_dev_t *hw)
{
return hw->mode_reg.rm;
}
/**
* @brief Set operating mode of TWAI controller
*
* @param hw Start address of the TWAI registers
* @param mode Operating mode
*
* @note Must be called in reset mode
*/
static inline void twai_ll_set_mode(twai_dev_t *hw, twai_mode_t mode)
{
if (mode == TWAI_MODE_NORMAL) { //Normal Operating mode
hw->mode_reg.lom = 0;
hw->mode_reg.stm = 0;
} else if (mode == TWAI_MODE_NO_ACK) { //Self Test Mode (No Ack)
hw->mode_reg.lom = 0;
hw->mode_reg.stm = 1;
} else if (mode == TWAI_MODE_LISTEN_ONLY) { //Listen Only Mode
hw->mode_reg.lom = 1;
hw->mode_reg.stm = 0;
}
}
/* --------------------------- Command Register ----------------------------- */
/**
* @brief Set TX command
*
* Setting the TX command will cause the TWAI controller to attempt to transmit
* the frame stored in the TX buffer. The TX buffer will be occupied (i.e.,
* locked) until TX completes.
*
* @param hw Start address of the TWAI registers
*
* @note Transmit commands should be called last (i.e., after handling buffer
* release and clear data overrun) in order to prevent the other commands
* overwriting this latched TX bit with 0.
*/
static inline void twai_ll_set_cmd_tx(twai_dev_t *hw)
{
hw->command_reg.tr = 1;
}
/**
* @brief Set single shot TX command
*
* Similar to setting TX command, but the TWAI controller will not automatically
* retry transmission upon an error (e.g., due to an acknowledgement error).
*
* @param hw Start address of the TWAI registers
*
* @note Transmit commands should be called last (i.e., after handling buffer
* release and clear data overrun) in order to prevent the other commands
* overwriting this latched TX bit with 0.
*/
static inline void twai_ll_set_cmd_tx_single_shot(twai_dev_t *hw)
{
hw->command_reg.val = 0x03; //Set command_reg.tr and command_reg.at simultaneously for single shot transmittion request
}
/**
* @brief Aborts TX
*
* Frames awaiting TX will be aborted. Frames already being TX are not aborted.
* Transmission Complete Status bit is automatically set to 1.
* Similar to setting TX command, but the TWAI controller will not automatically
* retry transmission upon an error (e.g., due to acknowledge error).
*
* @param hw Start address of the TWAI registers
*
* @note Transmit commands should be called last (i.e., after handling buffer
* release and clear data overrun) in order to prevent the other commands
* overwriting this latched TX bit with 0.
*/
static inline void twai_ll_set_cmd_abort_tx(twai_dev_t *hw)
{
hw->command_reg.at = 1;
}
/**
* @brief Release RX buffer
*
* Rotates RX buffer to the next frame in the RX FIFO.
*
* @param hw Start address of the TWAI registers
*/
static inline void twai_ll_set_cmd_release_rx_buffer(twai_dev_t *hw)
{
hw->command_reg.rrb = 1;
}
/**
* @brief Clear data overrun
*
* Clears the data overrun status bit
*
* @param hw Start address of the TWAI registers
*/
static inline void twai_ll_set_cmd_clear_data_overrun(twai_dev_t *hw)
{
hw->command_reg.cdo = 1;
}
/**
* @brief Set self reception single shot command
*
* Similar to setting TX command, but the TWAI controller also simultaneously
* receive the transmitted frame and is generally used for self testing
* purposes. The TWAI controller will not ACK the received message, so consider
* using the NO_ACK operating mode.
*
* @param hw Start address of the TWAI registers
*
* @note Transmit commands should be called last (i.e., after handling buffer
* release and clear data overrun) in order to prevent the other commands
* overwriting this latched TX bit with 0.
*/
static inline void twai_ll_set_cmd_self_rx_request(twai_dev_t *hw)
{
hw->command_reg.srr = 1;
}
/**
* @brief Set self reception request command
*
* Similar to setting the self reception request, but the TWAI controller will
* not automatically retry transmission upon an error (e.g., due to and
* acknowledgement error).
*
* @param hw Start address of the TWAI registers
*
* @note Transmit commands should be called last (i.e., after handling buffer
* release and clear data overrun) in order to prevent the other commands
* overwriting this latched TX bit with 0.
*/
static inline void twai_ll_set_cmd_self_rx_single_shot(twai_dev_t *hw)
{
hw->command_reg.val = 0x12; //Set command_reg.srr and command_reg.at simultaneously for single shot self reception request
}
/* --------------------------- Status Register ------------------------------ */
/**
* @brief Get all status bits
*
* @param hw Start address of the TWAI registers
* @return Status bits
*/
static inline uint32_t twai_ll_get_status(twai_dev_t *hw)
{
return hw->status_reg.val;
}
/**
* @brief Check if RX FIFO overrun status bit is set
*
* @param hw Start address of the TWAI registers
* @return Overrun status bit
*/
static inline bool twai_ll_is_fifo_overrun(twai_dev_t *hw)
{
return hw->status_reg.dos;
}
/**
* @brief Check if previously TX was successful
*
* @param hw Start address of the TWAI registers
* @return Whether previous TX was successful
*/
static inline bool twai_ll_is_last_tx_successful(twai_dev_t *hw)
{
return hw->status_reg.tcs;
}
//Todo: Add stand alone status bit check functions when necessary
/* -------------------------- Interrupt Register ---------------------------- */
/**
* @brief Get currently set interrupts
*
* Reading the interrupt registers will automatically clear all interrupts
* except for the Receive Interrupt.
*
* @param hw Start address of the TWAI registers
* @return Bit mask of set interrupts
*/
static inline uint32_t twai_ll_get_and_clear_intrs(twai_dev_t *hw)
{
return hw->interrupt_reg.val;
}
/* ----------------------- Interrupt Enable Register ------------------------ */
/**
* @brief Set which interrupts are enabled
*
* @param hw Start address of the TWAI registers
* @param Bit mask of interrupts to enable
*
* @note Must be called in reset mode
*/
static inline void twai_ll_set_enabled_intrs(twai_dev_t *hw, uint32_t intr_mask)
{
hw->interrupt_enable_reg.val = intr_mask;
}
/* ------------------------ Bus Timing Registers --------------------------- */
/**
* @brief Set bus timing
*
* @param hw Start address of the TWAI registers
* @param brp Baud Rate Prescaler
* @param sjw Synchronization Jump Width
* @param tseg1 Timing Segment 1
* @param tseg2 Timing Segment 2
* @param triple_sampling Triple Sampling enable/disable
*
* @note Must be called in reset mode
* @note ESP32S2 brp can be any even number between 2 to 32768
*/
static inline void twai_ll_set_bus_timing(twai_dev_t *hw, uint32_t brp, uint32_t sjw, uint32_t tseg1, uint32_t tseg2, bool triple_sampling)
{
hw->bus_timing_0_reg.brp = (brp / 2) - 1;
hw->bus_timing_0_reg.sjw = sjw - 1;
hw->bus_timing_1_reg.tseg1 = tseg1 - 1;
hw->bus_timing_1_reg.tseg2 = tseg2 - 1;
hw->bus_timing_1_reg.sam = triple_sampling;
}
/* ----------------------------- ALC Register ------------------------------- */
/**
* @brief Clear Arbitration Lost Capture Register
*
* Reading the ALC register rearms the Arbitration Lost Interrupt
*
* @param hw Start address of the TWAI registers
*/
static inline void twai_ll_clear_arb_lost_cap(twai_dev_t *hw)
{
(void)hw->arbitration_lost_captue_reg.val;
//Todo: Decode ALC register
}
/* ----------------------------- ECC Register ------------------------------- */
/**
* @brief Clear Error Code Capture register
*
* Reading the ECC register rearms the Bus Error Interrupt
*
* @param hw Start address of the TWAI registers
*/
static inline void twai_ll_clear_err_code_cap(twai_dev_t *hw)
{
(void)hw->error_code_capture_reg.val;
//Todo: Decode error code capture
}
/* ----------------------------- EWL Register ------------------------------- */
/**
* @brief Set Error Warning Limit
*
* @param hw Start address of the TWAI registers
* @param ewl Error Warning Limit
*
* @note Must be called in reset mode
*/
static inline void twai_ll_set_err_warn_lim(twai_dev_t *hw, uint32_t ewl)
{
hw->error_warning_limit_reg.ewl = ewl;
}
/**
* @brief Get Error Warning Limit
*
* @param hw Start address of the TWAI registers
* @return Error Warning Limit
*/
static inline uint32_t twai_ll_get_err_warn_lim(twai_dev_t *hw)
{
return hw->error_warning_limit_reg.val;
}
/* ------------------------ RX Error Count Register ------------------------- */
/**
* @brief Get RX Error Counter
*
* @param hw Start address of the TWAI registers
* @return REC value
*
* @note REC is not frozen in reset mode. Listen only mode will freeze it. A BUS
* OFF condition automatically sets the REC to 0.
*/
static inline uint32_t twai_ll_get_rec(twai_dev_t *hw)
{
return hw->rx_error_counter_reg.val;
}
/**
* @brief Set RX Error Counter
*
* @param hw Start address of the TWAI registers
* @param rec REC value
*
* @note Must be called in reset mode
*/
static inline void twai_ll_set_rec(twai_dev_t *hw, uint32_t rec)
{
hw->rx_error_counter_reg.rxerr = rec;
}
/* ------------------------ TX Error Count Register ------------------------- */
/**
* @brief Get TX Error Counter
*
* @param hw Start address of the TWAI registers
* @return TEC value
*
* @note A BUS OFF condition will automatically set this to 128
*/
static inline uint32_t twai_ll_get_tec(twai_dev_t *hw)
{
return hw->tx_error_counter_reg.val;
}
/**
* @brief Set TX Error Counter
*
* @param hw Start address of the TWAI registers
* @param tec TEC value
*
* @note Must be called in reset mode
*/
static inline void twai_ll_set_tec(twai_dev_t *hw, uint32_t tec)
{
hw->tx_error_counter_reg.txerr = tec;
}
/* ---------------------- Acceptance Filter Registers ----------------------- */
/**
* @brief Set Acceptance Filter
* @param hw Start address of the TWAI registers
* @param code Acceptance Code
* @param mask Acceptance Mask
* @param single_filter Whether to enable single filter mode
*
* @note Must be called in reset mode
*/
static inline void twai_ll_set_acc_filter(twai_dev_t* hw, uint32_t code, uint32_t mask, bool single_filter)
{
uint32_t code_swapped = __builtin_bswap32(code);
uint32_t mask_swapped = __builtin_bswap32(mask);
for (int i = 0; i < 4; i++) {
hw->acceptance_filter.acr[i].byte = ((code_swapped >> (i * 8)) & 0xFF);
hw->acceptance_filter.amr[i].byte = ((mask_swapped >> (i * 8)) & 0xFF);
}
hw->mode_reg.afm = single_filter;
}
/* ------------------------- TX/RX Buffer Registers ------------------------- */
/**
* @brief Copy a formatted TWAI frame into TX buffer for transmission
*
* @param hw Start address of the TWAI registers
* @param tx_frame Pointer to formatted frame
*
* @note Call twai_ll_format_frame_buffer() to format a frame
*/
static inline void twai_ll_set_tx_buffer(twai_dev_t *hw, twai_ll_frame_buffer_t *tx_frame)
{
//Copy formatted frame into TX buffer
for (int i = 0; i < 13; i++) {
hw->tx_rx_buffer[i].val = tx_frame->bytes[i];
}
}
/**
* @brief Copy a received frame from the RX buffer for parsing
*
* @param hw Start address of the TWAI registers
* @param rx_frame Pointer to store formatted frame
*
* @note Call twai_ll_prase_frame_buffer() to parse the formatted frame
*/
static inline void twai_ll_get_rx_buffer(twai_dev_t *hw, twai_ll_frame_buffer_t *rx_frame)
{
//Copy RX buffer registers into frame
for (int i = 0; i < 13; i++) {
rx_frame->bytes[i] = hw->tx_rx_buffer[i].byte;
}
}
/**
* @brief Format contents of a TWAI frame into layout of TX Buffer
*
* This function encodes a message into a frame structure. The frame structure
* has an identical layout to the TX buffer, allowing the frame structure to be
* directly copied into TX buffer.
*
* @param[in] 11bit or 29bit ID
* @param[in] dlc Data length code
* @param[in] data Pointer to an 8 byte array containing data. NULL if no data
* @param[in] format Type of TWAI frame
* @param[in] single_shot Frame will not be retransmitted on failure
* @param[in] self_rx Frame will also be simultaneously received
* @param[out] tx_frame Pointer to store formatted frame
*/
static inline void twai_ll_format_frame_buffer(uint32_t id, uint8_t dlc, const uint8_t *data,
uint32_t flags, twai_ll_frame_buffer_t *tx_frame)
{
bool is_extd = flags & TWAI_MSG_FLAG_EXTD;
bool is_rtr = flags & TWAI_MSG_FLAG_RTR;
//Set frame information
tx_frame->dlc = dlc;
tx_frame->frame_format = is_extd;
tx_frame->rtr = is_rtr;
tx_frame->self_reception = (flags & TWAI_MSG_FLAG_SELF) ? 1 : 0;
tx_frame->single_shot = (flags & TWAI_MSG_FLAG_SS) ? 1 : 0;
//Set ID. The ID registers are big endian and left aligned, therefore a bswap will be required
if (is_extd) {
uint32_t id_temp = __builtin_bswap32((id & TWAI_EXTD_ID_MASK) << 3); //((id << 3) >> 8*(3-i))
for (int i = 0; i < 4; i++) {
tx_frame->extended.id[i] = (id_temp >> (8 * i)) & 0xFF;
}
} else {
uint32_t id_temp = __builtin_bswap16((id & TWAI_STD_ID_MASK) << 5); //((id << 5) >> 8*(1-i))
for (int i = 0; i < 2; i++) {
tx_frame->standard.id[i] = (id_temp >> (8 * i)) & 0xFF;
}
}
uint8_t *data_buffer = (is_extd) ? tx_frame->extended.data : tx_frame->standard.data;
if (!is_rtr) { //Only copy data if the frame is a data frame (i.e not a remote frame)
for (int i = 0; (i < dlc) && (i < TWAI_FRAME_MAX_DLC); i++) {
data_buffer[i] = data[i];
}
}
}
/**
* @brief Parse formatted TWAI frame (RX Buffer Layout) into its constituent contents
*
* @param[in] rx_frame Pointer to formatted frame
* @param[out] id 11 or 29bit ID
* @param[out] dlc Data length code
* @param[out] data Data. Left over bytes set to 0.
* @param[out] format Type of TWAI frame
*/
static inline void twai_ll_prase_frame_buffer(twai_ll_frame_buffer_t *rx_frame, uint32_t *id, uint8_t *dlc,
uint8_t *data, uint32_t *flags)
{
//Copy frame information
*dlc = rx_frame->dlc;
uint32_t flags_temp = 0;
flags_temp |= (rx_frame->frame_format) ? TWAI_MSG_FLAG_EXTD : 0;
flags_temp |= (rx_frame->rtr) ? TWAI_MSG_FLAG_RTR : 0;
flags_temp |= (rx_frame->dlc > TWAI_FRAME_MAX_DLC) ? TWAI_MSG_FLAG_DLC_NON_COMP : 0;
*flags = flags_temp;
//Copy ID. The ID registers are big endian and left aligned, therefore a bswap will be required
if (rx_frame->frame_format) {
uint32_t id_temp = 0;
for (int i = 0; i < 4; i++) {
id_temp |= rx_frame->extended.id[i] << (8 * i);
}
id_temp = __builtin_bswap32(id_temp) >> 3; //((byte[i] << 8*(3-i)) >> 3)
*id = id_temp & TWAI_EXTD_ID_MASK;
} else {
uint32_t id_temp = 0;
for (int i = 0; i < 2; i++) {
id_temp |= rx_frame->standard.id[i] << (8 * i);
}
id_temp = __builtin_bswap16(id_temp) >> 5; //((byte[i] << 8*(1-i)) >> 5)
*id = id_temp & TWAI_STD_ID_MASK;
}
uint8_t *data_buffer = (rx_frame->frame_format) ? rx_frame->extended.data : rx_frame->standard.data;
//Only copy data if the frame is a data frame (i.e. not a remote frame)
int data_length = (rx_frame->rtr) ? 0 : ((rx_frame->dlc > TWAI_FRAME_MAX_DLC) ? TWAI_FRAME_MAX_DLC : rx_frame->dlc);
for (int i = 0; i < data_length; i++) {
data[i] = data_buffer[i];
}
//Set remaining bytes of data to 0
for (int i = data_length; i < TWAI_FRAME_MAX_DLC; i++) {
data[i] = 0;
}
}
/* ----------------------- RX Message Count Register ------------------------ */
/**
* @brief Get RX Message Counter
*
* @param hw Start address of the TWAI registers
* @return RX Message Counter
*/
static inline uint32_t twai_ll_get_rx_msg_count(twai_dev_t *hw)
{
return hw->rx_message_counter_reg.val;
}
/* ------------------------- Clock Divider Register ------------------------- */
/**
* @brief Set CLKOUT Divider and enable/disable
*
* Configure CLKOUT. CLKOUT is a pre-scaled version of APB CLK. Divider can be
* 1, or any even number from 2 to 490. Set the divider to 0 to disable CLKOUT.
*
* @param hw Start address of the TWAI registers
* @param divider Divider for CLKOUT (any even number from 2 to 490). Set to 0 to disable CLKOUT
*/
static inline void twai_ll_set_clkout(twai_dev_t *hw, uint32_t divider)
{
if (divider >= 2 && divider <= 490) {
hw->clock_divider_reg.co = 0;
hw->clock_divider_reg.cd = (divider / 2) - 1;
} else if (divider == 1) {
//Setting the divider reg to max value (255) means a divider of 1
hw->clock_divider_reg.co = 0;
hw->clock_divider_reg.cd = 255;
} else {
hw->clock_divider_reg.co = 1;
hw->clock_divider_reg.cd = 0;
}
}
#ifdef __cplusplus
}
#endif
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