254 lines
12 KiB
C
254 lines
12 KiB
C
/****************************************************************************************
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| Description: bootloader CAN communication interface source file
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| File Name: can.c
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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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| 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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| 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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| You should have received a copy of the GNU General Public License along with OpenBLT.
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| If not, see <http://www.gnu.org/licenses/>.
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| A special exception to the GPL is included to allow you to distribute a combined work
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| that includes OpenBLT without being obliged to provide the source code for any
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| proprietary components. The exception text is included at the bottom of the license
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| file <license.html>.
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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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#define CAN_TBS1 (0x00000004) /* transmit buffer 1 idle */
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#define CAN_TCS1 (0x00000008) /* transmit buffer 1 complete */
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#define CAN_RRB (0x04) /* receive buffer release */
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#define CAN_RBS (0x01) /* receive buffer status */
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#define CAN_TR (0x01) /* transmission request */
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#define CAN_STB1 (0x20) /* select tx buffer 1 for transmit */
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/****************************************************************************************
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* Register definitions
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****************************************************************************************/
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#define CANAFMR (*((volatile blt_int8u *) 0xE003C000))
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#define CAN1MOD (*((volatile blt_int32u *) 0xE0044000))
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#define CAN1IER (*((volatile blt_int32u *) 0xE0044010))
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#define CAN1GSR (*((volatile blt_int32u *) 0xE0044008))
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#define CAN1BTR (*((volatile blt_int32u *) 0xE0044014))
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#define CAN1TFI1 (*((volatile blt_int32u *) 0xE0044030))
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#define CAN1TID1 (*((volatile blt_int32u *) 0xE0044034))
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#define CAN1TDA1 (*((volatile blt_int32u *) 0xE0044038))
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#define CAN1TDB1 (*((volatile blt_int32u *) 0xE004403C))
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#define CAN1CMR (*((volatile blt_int32u *) 0xE0044004))
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#define CAN1SR (*((volatile blt_int32u *) 0xE004401C))
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#define CAN1RID (*((volatile blt_int32u *) 0xE0044024))
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#define CAN1RDA (*((volatile blt_int32u *) 0xE0044028))
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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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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; /* bus timing structure type */
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/****************************************************************************************
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* Local constant declarations
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****************************************************************************************/
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/* According to the CAN protocol 1 bit-time can be made up of between 8..25 time quanta
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* (TQ). The total TQ in a bit is SYNC + TSEG1 + TSEG2 with SYNC always being 1.
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* The sample point is (SYNC + TSEG1) / (SYNC + TSEG1 + SEG2) * 100%. This array contains
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* possible and valid time quanta configurations with a sample point between 68..78%.
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*/
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static const tCanBusTiming canTiming[] =
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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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** NAME: CanGetSpeedConfig
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** PARAMETER: baud The desired baudrate in kbps. Valid values are 10..1000.
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** btr Pointer to where the value for register CANxBTR will be stored.
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** RETURN VALUE: BLT_TRUE if the CAN bustiming register values were found, BLT_FALSE
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** otherwise.
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** DESCRIPTION: Search algorithm to match the desired baudrate to a possible bus
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** timing configuration.
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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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** NAME: CanInit
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** PARAMETER: none
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** RETURN VALUE: none
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** DESCRIPTION: Initializes the CAN controller and synchronizes it to the CAN bus.
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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;
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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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** NAME: CanTransmitPacket
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** PARAMETER: data pointer to byte array with data that it to be transmitted.
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** len number of bytes that are to be transmitted.
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** RETURN VALUE: none
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** DESCRIPTION: Transmits a packet formatted for the communication interface.
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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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/* 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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** NAME: CanReceivePacket
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** PARAMETER: data pointer to byte array where the data is to be stored.
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** RETURN VALUE: BLT_TRUE is a packet was received, BLT_FALSE otherwise.
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** DESCRIPTION: Receives a communication interface packet if one is present.
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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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/* check if a new message was received */
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if ((CAN1SR & CAN_RBS) == 0)
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{
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return BLT_FALSE;
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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 (CAN1RID != BOOT_COM_CAN_RX_MSG_ID)
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{
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return BLT_FALSE;
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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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/* release the receive buffer */
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CAN1CMR = CAN_RRB;
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/* inform called that a new data was received */
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return BLT_TRUE;
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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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