274 lines
13 KiB
C
274 lines
13 KiB
C
/************************************************************************************//**
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* \file Source/_template/can.c
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* \brief Bootloader CAN communication interface source file.
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* \ingroup Target__template_can
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* \internal
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*----------------------------------------------------------------------------------------
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* C O P Y R I G H T
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*----------------------------------------------------------------------------------------
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* Copyright (c) 2019 by Feaser http://www.feaser.com All rights reserved
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*
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*----------------------------------------------------------------------------------------
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* L I C E N S E
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*----------------------------------------------------------------------------------------
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* This file is part of OpenBLT. OpenBLT is free software: you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as published by the Free
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* Software Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* OpenBLT is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU General Public License for more details.
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*
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* You have received a copy of the GNU General Public License along with OpenBLT. It
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* should be located in ".\Doc\license.html". If not, contact Feaser to obtain a copy.
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*
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* \endinternal
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****************************************************************************************/
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/************************************************************************************//**
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* \defgroup Target__template_can CAN driver of a port
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* \brief This module implements the CAN driver of a microcontroller port.
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* \details For the most parts, this driver is already implemented. The only parts that
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* need porting are the UART initialization, byte reception and byte
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* transmission.
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* \ingroup Target__template
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****************************************************************************************/
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/****************************************************************************************
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* Include files
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****************************************************************************************/
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#include "boot.h" /* bootloader generic header */
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#if (BOOT_COM_CAN_ENABLE > 0)
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/* TODO ##Port Include microcontroller peripheral driver header files here. */
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/****************************************************************************************
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* Macro definitions
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****************************************************************************************/
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/** \brief Timeout for transmitting a CAN message in milliseconds. */
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#define CAN_MSG_TX_TIMEOUT_MS (50u)
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/****************************************************************************************
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* Type definitions
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****************************************************************************************/
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/** \brief Structure type for grouping CAN bus timing related information. */
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typedef struct t_can_bus_timing
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{
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blt_int8u tseg1; /**< CAN time segment 1 */
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blt_int8u tseg2; /**< CAN time segment 2 */
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} tCanBusTiming;
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/****************************************************************************************
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* Local constant declarations
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****************************************************************************************/
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/** \brief CAN bittiming table for dynamically calculating the bittiming settings.
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* \details According to the CAN protocol 1 bit-time can be made up of between 8..25
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* time quanta (TQ). The total TQ in a bit is SYNC + TSEG1 + TSEG2 with SYNC
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* always being 1. The sample point is (SYNC + TSEG1) / (SYNC + TSEG1 + SEG2) *
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* 100%. This array contains possible and valid time quanta configurations with
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* a sample point between 68..78%.
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*/
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static const tCanBusTiming canTiming[] =
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{
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/* TQ | TSEG1 | TSEG2 | SP */
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/* ------------------------- */
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{ 5, 2 }, /* 8 | 5 | 2 | 75% */
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{ 6, 2 }, /* 9 | 6 | 2 | 78% */
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{ 6, 3 }, /* 10 | 6 | 3 | 70% */
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{ 7, 3 }, /* 11 | 7 | 3 | 73% */
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{ 8, 3 }, /* 12 | 8 | 3 | 75% */
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{ 9, 3 }, /* 13 | 9 | 3 | 77% */
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{ 9, 4 }, /* 14 | 9 | 4 | 71% */
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{ 10, 4 }, /* 15 | 10 | 4 | 73% */
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{ 11, 4 }, /* 16 | 11 | 4 | 75% */
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{ 12, 4 }, /* 17 | 12 | 4 | 76% */
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{ 12, 5 }, /* 18 | 12 | 5 | 72% */
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{ 13, 5 }, /* 19 | 13 | 5 | 74% */
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{ 14, 5 }, /* 20 | 14 | 5 | 75% */
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{ 15, 5 }, /* 21 | 15 | 5 | 76% */
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{ 15, 6 }, /* 22 | 15 | 6 | 73% */
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{ 16, 6 }, /* 23 | 16 | 6 | 74% */
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{ 16, 7 }, /* 24 | 16 | 7 | 71% */
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{ 16, 8 } /* 25 | 16 | 8 | 68% */
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};
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/************************************************************************************//**
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** \brief Search algorithm to match the desired baudrate to a possible bus
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** timing configuration.
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** \param baud The desired baudrate in kbps. Valid values are 10..1000.
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** \param prescaler Pointer to where the value for the prescaler will be stored.
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** \param tseg1 Pointer to where the value for TSEG2 will be stored.
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** \param tseg2 Pointer to where the value for TSEG2 will be stored.
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** \return BLT_TRUE if the CAN bustiming register values were found, BLT_FALSE
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** otherwise.
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**
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****************************************************************************************/
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static blt_bool CanGetSpeedConfig(blt_int16u baud, blt_int16u *prescaler,
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blt_int8u *tseg1, blt_int8u *tseg2)
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{
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blt_int8u cnt;
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blt_int32u canClockFreqkHz;
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/* TODO ##Port This helper function assists with getting a compatible bittiming
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* configuration, based on the specified 'baud' communication speed on the CAN bus in
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* kbps. This function needs two microcontroller specific values: (1) the speed of
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* the clock that sources the CAN peripheral and (2) the supported range of the
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* prescaler that for scaling down the CAN peripheral clock speed.
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*/
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/* TODO ##Port Set the clock speed of the CAN peripheral in kHz. You can used the
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* macros BOOT_CPU_XTAL_SPEED_KHZ and BOOT_CPU_SYSTEM_SPEED_KHZ if applicable.
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*/
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canClockFreqkHz = BOOT_CPU_XTAL_SPEED_KHZ;
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/* loop through all possible time quanta configurations to find a match */
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for (cnt=0; cnt < sizeof(canTiming)/sizeof(canTiming[0]); cnt++)
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{
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if ((canClockFreqkHz % (baud*(canTiming[cnt].tseg1+canTiming[cnt].tseg2+1))) == 0)
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{
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/* compute the prescaler that goes with this TQ configuration */
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*prescaler = canClockFreqkHz/(baud*(canTiming[cnt].tseg1+canTiming[cnt].tseg2+1));
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/* TODO ##Port Update the prescaler range that is supported by the CAN peripheral
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* on the microcontroller. The example implementation is for a prescaler that can
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* be in the 1 - 1024 range.
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*/
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/* make sure the prescaler is valid */
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if ((*prescaler > 0) && (*prescaler <= 1024))
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{
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/* store the bustiming configuration */
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*tseg1 = canTiming[cnt].tseg1;
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*tseg2 = canTiming[cnt].tseg2;
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/* found a good bus timing configuration */
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return BLT_TRUE;
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}
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}
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}
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/* could not find a good bus timing configuration */
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return BLT_FALSE;
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} /*** end of CanGetSpeedConfig ***/
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/************************************************************************************//**
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** \brief Initializes the CAN controller and synchronizes it to the CAN bus.
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** \return none.
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**
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****************************************************************************************/
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void CanInit(void)
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{
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blt_int16u prescaler = 0;
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blt_int8u tseg1 = 0, tseg2 = 0;
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/* TODO ##Port Perform compile time assertion to check that the configured CAN channel
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* is actually supported by this driver. The example is for a driver where CAN
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* channels 0 - 1 are supported.
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*/
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ASSERT_CT((BOOT_COM_CAN_CHANNEL_INDEX == 0 || BOOT_COM_CAN_CHANNEL_INDEX == 1));
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/* obtain bittiming configuration information. */
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if (CanGetSpeedConfig(BOOT_COM_CAN_BAUDRATE/1000, &prescaler, &tseg1, &tseg2) == BLT_FALSE)
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{
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/* Incorrect configuration. The specified baudrate is not supported for the given
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* clock configuration. Verify the following settings in blt_conf.h:
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* - BOOT_COM_CAN_BAUDRATE
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* - BOOT_CPU_XTAL_SPEED_KHZ
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* - BOOT_CPU_SYSTEM_SPEED_KHZ
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*/
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ASSERT_RT(BLT_FALSE);
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}
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/* TODO ##Vg Perform the configuration and initialization of the CAN controller. Note
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* that the bittiming related values are already stored in 'prescaler, 'tseg1', and
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* 'tseg2'. There values are ready to be used. Typically, the following tasks need
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* to be performed:
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* (1) Place the CAN controller in initialization mode.
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* (2) Disable all CAN related interrupts as the bootloader runs in polling mode.
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* (3) Configure the bittiming based on: 'prescaler', 'tseg1' and 'tseg2'. It is okay
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* to configure 1 time quanta for the synchronization jump width (SWJ).
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* (4) Configure one transmit message object. It will be used in CanTransmitPacket()
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* to transmit a CAN message with identifier BOOT_COM_CAN_TX_MSG_ID. Note that if
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* the 0x80000000 bit is set in this identifier, it means that it is a 29-bit CAN
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* identifier instead of an 11-bit.
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* (5) Configure at least one reception message object and configure its reception
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* acceptance filter such that only the CAN identifier BOOT_COM_CAN_RX_MSG_ID is
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* received. Note that if the 0x80000000 bit is set in this identifier, it means
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* that it is a 29-bit CAN identifier instead of an 11-bit.
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* (6) Leave the initialization mode and place the CAN controller in operational mode.
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*/
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} /*** end of CanInit ***/
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/************************************************************************************//**
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** \brief Transmits a packet formatted for the communication interface.
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** \param data Pointer to byte array with data that it to be transmitted.
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** \param len Number of bytes that are to be transmitted.
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** \return none.
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**
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****************************************************************************************/
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void CanTransmitPacket(blt_int8u *data, blt_int8u len)
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{
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blt_int32u timeout;
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/* TODO ##Port Configure the transmit message object for transmitting a CAN message
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* with CAN identifier BOOT_COM_CAN_TX_MSG_ID. Note that if the 0x80000000 bit is set
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* in this identifier, it means that it is a 29-bit CAN identifier instead of an
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* 11-bit. Next, copy the message data to the transmit message object. The number
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* of data bytes is in 'len' and the actual data byte values are in array 'data'.
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* Once done, start the transmission of the message that was just stored in the
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* transmit message object.
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*/
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/* TODO ##Port Wait for the message transmission to complete, with timeout though to
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* make sure this function doesn't hang in case of an error. This is typically achieved
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* by evaluating a transmit complete flag in a register of the transmit message object.
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*/
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/* determine timeout time for the transmit completion. */
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timeout = TimerGet() + CAN_MSG_TX_TIMEOUT_MS;
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/* poll for completion of the transmit operation. */
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while (1 == 0)
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{
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/* service the watchdog. */
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CopService();
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/* break loop upon timeout. this would indicate a hardware failure or no other
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* nodes connected to the bus.
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*/
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if (TimerGet() > timeout)
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{
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break;
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}
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}
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} /*** end of CanTransmitPacket ***/
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/************************************************************************************//**
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** \brief Receives a communication interface packet if one is present.
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** \param data Pointer to byte array where the data is to be stored.
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** \param len Pointer where the length of the packet is to be stored.
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** \return BLT_TRUE is a packet was received, BLT_FALSE otherwise.
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**
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****************************************************************************************/
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blt_bool CanReceivePacket(blt_int8u *data, blt_int8u *len)
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{
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blt_bool result = BLT_FALSE;
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/* TODO ##Port Check for the reception of a new CAN message with identifier
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* BOOT_COM_CAN_RX_MSG_ID. Note that if the 0x80000000 bit is set in this identifier,
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* it means that it is a 29-bit CAN identifier instead of an 11-bit.
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* If a new message with this CAN identifier was received, store the data byte values
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* in array 'data' and store the number of data bytes in 'len'. Finally, set 'result'
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* to BLT_TRUE to indicate to the caller of this function that a new CAN message was
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* received and stored.
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*/
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/* give the result back to the caller */
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return result;
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} /*** end of CanReceivePacket ***/
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#endif /* BOOT_COM_CAN_ENABLE > 0 */
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/*********************************** end of can.c **************************************/
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