Andrew Boyson / lpc1768

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Dependents:   test-lpc1768 oldheating gps motorhome ... more

can/can.c@71:2f8af23950de, 2022-06-03 (annotated)

Committer:
andrewboyson
Date:
Fri Jun 03 11:51:13 2022 +0000
Revision:
71:2f8af23950de
Added can module

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 71:2f8af23950de 1
andrewboyson 71:2f8af23950de 2 #include "log.h"
andrewboyson 71:2f8af23950de 3 #include "mstimer.h"
andrewboyson 71:2f8af23950de 4
andrewboyson 71:2f8af23950de 5 #define AFMR *((volatile unsigned *)0x4003C000) // Acceptance Filter Mode Register
andrewboyson 71:2f8af23950de 6
andrewboyson 71:2f8af23950de 7 #define CAN2MOD *((volatile unsigned *)0x40048000) // CAN Mode register
andrewboyson 71:2f8af23950de 8 #define CAN2CMR *((volatile unsigned *)0x40048004) // CAN Command register
andrewboyson 71:2f8af23950de 9 #define CAN2GSR *((volatile unsigned *)0x40048008) // CAN Global Status register
andrewboyson 71:2f8af23950de 10 #define CAN2ICR *((volatile unsigned *)0x4004800C) // CAN Interrupt and Capture Register
andrewboyson 71:2f8af23950de 11 #define CAN2IER *((volatile unsigned *)0x40048010) // CAN Interrupt Enable Register
andrewboyson 71:2f8af23950de 12 #define CAN2BTR *((volatile unsigned *)0x40048014) // CAN Bus Timing Register
andrewboyson 71:2f8af23950de 13 #define CAN2TFI1 *((volatile unsigned *)0x40048030) // CAN Transmit Frame Information register
andrewboyson 71:2f8af23950de 14 #define CAN2TID1 *((volatile unsigned *)0x40048034) // CAN Transmit Identifier Register
andrewboyson 71:2f8af23950de 15 #define CAN2TDA1 *((volatile unsigned *)0x40048038) // CAN Transmit Data Register A
andrewboyson 71:2f8af23950de 16 #define CAN2TDB1 *((volatile unsigned *)0x4004803C) // CAN Transmit Data Register B
andrewboyson 71:2f8af23950de 17 #define CAN2RFS *((volatile unsigned *)0x40048020) // CAN Receive Frame Status register
andrewboyson 71:2f8af23950de 18 #define CAN2RID *((volatile unsigned *)0x40048024) // CAN Receive Identifier register
andrewboyson 71:2f8af23950de 19 #define CAN2RDA *((volatile unsigned *)0x40048028) // CAN Receive Data register A
andrewboyson 71:2f8af23950de 20 #define CAN2RDB *((volatile unsigned *)0x4004802C) // CAN Receive Data register B
andrewboyson 71:2f8af23950de 21
andrewboyson 71:2f8af23950de 22 void (*CanReceive)(uint16_t id, int length, uint32_t dataA, uint32_t dataB);
andrewboyson 71:2f8af23950de 23 void CanInit()
andrewboyson 71:2f8af23950de 24 {
andrewboyson 71:2f8af23950de 25 LogTime("Can init started\r\n");
andrewboyson 71:2f8af23950de 26 /*
andrewboyson 71:2f8af23950de 27 00: BRP = 95 : Clock is 96 / 4 = 24MHz and we want 1.000MHz so prescale by BRP+1 = 24: BRP = 23.
andrewboyson 71:2f8af23950de 28 14: SJW = 3 : 4 can clocks
andrewboyson 71:2f8af23950de 29 16: TESG1 = 4 : 5 can clocks
andrewboyson 71:2f8af23950de 30 20: TESG2 = 3 : 4 can clocks
andrewboyson 71:2f8af23950de 31 */
andrewboyson 71:2f8af23950de 32 CAN2BTR = 0;
andrewboyson 71:2f8af23950de 33 CAN2BTR |= 23 << 00;
andrewboyson 71:2f8af23950de 34 CAN2BTR |= 3 << 14;
andrewboyson 71:2f8af23950de 35 CAN2BTR |= 4 << 16;
andrewboyson 71:2f8af23950de 36 CAN2BTR |= 3 << 20;
andrewboyson 71:2f8af23950de 37
andrewboyson 71:2f8af23950de 38 AFMR |= 1 << 1; //Accept all messages
andrewboyson 71:2f8af23950de 39
andrewboyson 71:2f8af23950de 40 CAN2MOD = 0; //Controller to operating mode
andrewboyson 71:2f8af23950de 41 }
andrewboyson 71:2f8af23950de 42 void CanSend(uint16_t id, int length, uint32_t dataA, uint32_t dataB)
andrewboyson 71:2f8af23950de 43 {
andrewboyson 71:2f8af23950de 44 if (length > 8) length = 8;
andrewboyson 71:2f8af23950de 45 CAN2CMR |= 1 << 5; //STB1 Select Tx Buffer 1
andrewboyson 71:2f8af23950de 46 CAN2TFI1 = 0;
andrewboyson 71:2f8af23950de 47 CAN2TFI1 |= length << 16; //DLC Data Length Code
andrewboyson 71:2f8af23950de 48 CAN2TFI1 |= 0 << 30; //RTR Remote TRansmission
andrewboyson 71:2f8af23950de 49 CAN2TFI1 |= 0 << 31; // FF Extended frame (0 = 11 bit id; 1 = 29 bit id)
andrewboyson 71:2f8af23950de 50 CAN2TID1 = id;
andrewboyson 71:2f8af23950de 51 CAN2TDA1 = dataA;
andrewboyson 71:2f8af23950de 52 CAN2TDB1 = dataB;
andrewboyson 71:2f8af23950de 53 CAN2CMR |= 1 << 0; //TR Transmission Request
andrewboyson 71:2f8af23950de 54 }
andrewboyson 71:2f8af23950de 55 void CanMain()
andrewboyson 71:2f8af23950de 56 {
andrewboyson 71:2f8af23950de 57 if (CAN2GSR & 0x01) //RBS Receive Buffer Status - At least one complete message is available in CANxRFS CANxRID CANxRDA CANxRDB
andrewboyson 71:2f8af23950de 58 {
andrewboyson 71:2f8af23950de 59 uint16_t id = CAN2RID & 0x3FF;
andrewboyson 71:2f8af23950de 60 int length = (CAN2RFS >> 16) & 0xF;
andrewboyson 71:2f8af23950de 61 CanReceive(id, length, CAN2RDA, CAN2RDB);
andrewboyson 71:2f8af23950de 62 CAN2CMR |= 1 << 2; //RRB Release Receive Buffer
andrewboyson 71:2f8af23950de 63 }
andrewboyson 71:2f8af23950de 64 }