293 lines
13 KiB
C
293 lines
13 KiB
C
/************************************************************************************//**
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* \file Source\ARM7_LPC2000\can.c
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* \brief Bootloader CAN communication interface source file.
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* \ingroup Target_ARM7_LPC2000
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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) 2011 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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* 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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/****************************************************************************************
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* Macro definitions
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****************************************************************************************/
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/** \brief Transmit buffer 1 idle bit. */
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#define CAN_TBS1 (0x00000004)
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/** \brief Transmit buffer 1 complete bit. */
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#define CAN_TCS1 (0x00000008)
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/** \brief Receive buffer release bit. */
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#define CAN_RRB (0x04)
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/** \brief Receive buffer status bit. */
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#define CAN_RBS (0x01)
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/** \brief Transmission request bit. */
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#define CAN_TR (0x01)
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/** \brief Select tx buffer 1 for transmit bit. */
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#define CAN_STB1 (0x20)
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/** \brief Frame format bit. 0 for 11-bit and 1 for 29-bit CAN identifiers. */
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#define CAN_FF (0x80000000)
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/****************************************************************************************
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* Register definitions
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****************************************************************************************/
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/** \brief CANAFMR CAN controller register. */
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#define CANAFMR (*((volatile blt_int8u *) 0xE003C000))
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/** \brief CAN1MOD CAN controller register. */
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#define CAN1MOD (*((volatile blt_int32u *) 0xE0044000))
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/** \brief CAN1IER CAN controller register. */
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#define CAN1IER (*((volatile blt_int32u *) 0xE0044010))
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/** \brief CAN1GSR CAN controller register. */
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#define CAN1GSR (*((volatile blt_int32u *) 0xE0044008))
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/** \brief CAN1BTR CAN controller register. */
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#define CAN1BTR (*((volatile blt_int32u *) 0xE0044014))
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/** \brief CAN1TFI1 CAN controller register. */
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#define CAN1TFI1 (*((volatile blt_int32u *) 0xE0044030))
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/** \brief CAN1TID1 CAN controller register. */
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#define CAN1TID1 (*((volatile blt_int32u *) 0xE0044034))
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/** \brief CAN1TDA1 CAN controller register. */
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#define CAN1TDA1 (*((volatile blt_int32u *) 0xE0044038))
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/** \brief CAN1TDB1 CAN controller register. */
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#define CAN1TDB1 (*((volatile blt_int32u *) 0xE004403C))
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/** \brief CAN1CMR CAN controller register. */
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#define CAN1CMR (*((volatile blt_int32u *) 0xE0044004))
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/** \brief CAN1SR CAN controller register. */
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#define CAN1SR (*((volatile blt_int32u *) 0xE004401C))
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/** \brief CAN1RFS CAN controller register. */
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#define CAN1RFS (*((volatile blt_int32u *) 0xE0044020))
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/** \brief CAN1RID CAN controller register. */
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#define CAN1RID (*((volatile blt_int32u *) 0xE0044024))
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/** \brief CAN1RDA CAN controller register. */
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#define CAN1RDA (*((volatile blt_int32u *) 0xE0044028))
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/** \brief CAN1RDB CAN controller register. */
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#define CAN1RDB (*((volatile blt_int32u *) 0xE004402C))
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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 btr Pointer to where the value for register CANxBTR 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_int32u *btr)
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{
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blt_int16u prescaler;
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blt_int8u cnt;
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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 ((BOOT_CPU_SYSTEM_SPEED_KHZ % (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 = BOOT_CPU_SYSTEM_SPEED_KHZ/(baud*(canTiming[cnt].tseg1+canTiming[cnt].tseg2+1));
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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 prescaler and bustiming register value */
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*btr = prescaler - 1;
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*btr |= ((canTiming[cnt].tseg2 - 1) << 20) | ((canTiming[cnt].tseg1 - 1) << 16);
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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_bool result;
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blt_int32u btr_reg_value=0;
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/* the current implementation supports CAN1, which has channel index 0. throw an
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* assertion error in case a different CAN channel is configured.
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*/
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ASSERT_CT(BOOT_COM_CAN_CHANNEL_INDEX == 0);
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/* configure acceptance filter for bypass mode so it receives all messages */
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CANAFMR = 0x00000002L;
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/* take CAN controller offline and go into reset mode */
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CAN1MOD = 1;
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/* disable all interrupts. driver only needs to work in polling mode */
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CAN1IER = 0;
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/* reset CAN controller status */
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CAN1GSR = 0;
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/* configure the bittiming */
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result = CanGetSpeedConfig(BOOT_COM_CAN_BAUDRATE/1000, &btr_reg_value);
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/* check that a valid baudrate configuration was found */
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ASSERT_RT(result == BLT_TRUE);
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/* write the bittiming configuration to the register */
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CAN1BTR = btr_reg_value;
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/* enter normal operating mode and synchronize to the CAN bus */
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CAN1MOD = 0;
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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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/* check that transmit buffer 1 is ready to accept a new message */
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ASSERT_RT((CAN1SR & CAN_TBS1) != 0);
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/* write dlc and configure message as a standard message with 11-bit identifier */
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CAN1TFI1 = (len << 16);
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/* write the message identifier */
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CAN1TID1 = BOOT_COM_CAN_TX_MSG_ID;
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/* is it a 29-bit CAN identifier? */
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if ( (BOOT_COM_CAN_TX_MSG_ID & 0x80000000) != 0)
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{
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/* configure identifier as 29-bit extended. */
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CAN1TFI1 |= CAN_FF;
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/* Reset the mask bit. */
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CAN1TID1 &= ~0x80000000;
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}
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/* write the first set of 4 data bytes */
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CAN1TDA1 = (data[3] << 24) + (data[2] << 16) + (data[1] << 8) + data[0];
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/* write the second set of 4 data bytes */
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CAN1TDB1 = (data[7] << 24) + (data[6] << 16) + (data[5] << 8) + data[4];
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/* write transmission request for transmit buffer 1 */
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CAN1CMR = CAN_TR | CAN_STB1;
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/* wait for transmit completion */
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while ((CAN1SR & CAN_TCS1) == 0)
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{
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/* keep the watchdog happy */
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CopService();
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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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** \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)
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{
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blt_int32u rxMsgId;
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blt_bool result = BLT_FALSE;
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/* check if a new message was received */
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if ((CAN1SR & CAN_RBS) != 0)
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{
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/* read out the CAN message identifier */
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rxMsgId = CAN1RID;
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/* was is a 29-bit extended CAN identifier? */
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if ((CAN1RFS & CAN_FF) != 0)
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{
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/* set mask bit. */
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rxMsgId |= 0x80000000;
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}
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/* see if this is the message identifier that we are interested in */
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if (rxMsgId == BOOT_COM_CAN_RX_MSG_ID)
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{
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/* store the message data */
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data[0] = (blt_int8u)CAN1RDA;
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data[1] = (blt_int8u)(CAN1RDA >> 8);
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data[2] = (blt_int8u)(CAN1RDA >> 16);
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data[3] = (blt_int8u)(CAN1RDA >> 24);
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data[4] = (blt_int8u)CAN1RDB;
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data[5] = (blt_int8u)(CAN1RDB >> 8);
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data[6] = (blt_int8u)(CAN1RDB >> 16);
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data[7] = (blt_int8u)(CAN1RDB >> 24);
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/* update the result. */
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result = BLT_TRUE;
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}
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/* release the receive buffer */
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CAN1CMR = CAN_RRB;
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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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