MCP2515 CAN library
Fork of mcp2515 by
mcp2515.cpp
- Committer:
- driscoll85
- Date:
- 2017-07-24
- Revision:
- 13:ff12c7f532f9
- Parent:
- 11:b364adad6f08
File content as of revision 13:ff12c7f532f9:
/****************************************************************************** * * Controller Area Network (CAN) Demo-Application * Atmel AVR with Microchip MCP2515 * * Copyright (C) 2005 Martin THOMAS, Kaiserslautern, Germany * <eversmith@heizung-thomas.de> * http://www.siwawi.arubi.uni-kl.de/avr_projects * ***************************************************************************** * * File : mcp2515.c * Version : 0.9 * * Summary : MCP2515 "low-level" driver * * Parts of this code are adapted from a MCP2510 sample-application * by KVASER AB, http://www.kvaser.com (KVASER-code is marked as free) * * This code-module is free to use but you have to keep the copyright * notice. * * ***************************************************************************** * * File : mcp2515.cpp (mbed LPC1768 version) * Version : 0.1 * * All credits to the nerds above, this source has been adapted for the * LPC1768 platform by J.Engelman. And doesn't require and of the copyrighted * SPI or AVR controller code that Martin or co have excluded copyright. * This module remains free. * * *****************************************************************************/ #include "mcp2515.h" #include "mbed.h" #include "mcp2515_can.h" #include "mcp2515_defs.h" #include "mcp2515_bittime.h" #define SPI_NULL (0x00) #define PHSEG11 4 #define PHSEG21 1 #define BTLMODE2 7 //BTLMODE 0x80 (128) #define BRP2 2 #define BRP1 1 #define BRP0 0 #define CNF2_BTLMODE 0x80 #define CNF3 0x28 #define CNF3_SOF 0x08 #define CNF3_WAKFIL 0x04 #define CNF3_PHSEG2_MASK 0x07 mcp2515::mcp2515(SPI& _spi, PinName ncs) : spi(_spi), _ncs(ncs) { printf("\n\rmcp2515 = %d",this); printf("\n\rpin = %d",ncs); } void mcp2515::_reset() { _select(); _spi_readwrite(MCP_RESET); _deselect(); wait(0.001); } void mcp2515::setRegister( uint8_t address, uint8_t value) { _select(); _spi_readwrite(MCP_WRITE); _spi_readwrite(address); _spi_readwrite(value); _deselect(); } uint8_t mcp2515::configRate( uint8_t canSpeed) { uint8_t set, cfg1, cfg2, cfg3; set = 0; switch (canSpeed) { case (CAN_500KBPS_8MHZ) : cfg1 = 0x04; cfg2 = 0xA0; cfg3 = 0x02; case (CAN_50KBPS_8MHZ) : cfg1 = 0x04; //0x09; cfg2 = 0xB8; //0x90; cfg3 = 0x05; //0x02; case (CAN_125KBPS) : cfg1 = MCP_4MHz_125kBPS_CFG1 ; cfg2 = MCP_4MHz_125kBPS_CFG2 ; cfg3 = MCP_4MHz_125kBPS_CFG3 ; set = 1; break; case (CAN_20KBPS) : cfg1 = MCP_4MHz_20kBPS_CFG1 ; cfg2 = MCP_4MHz_20kBPS_CFG2 ; cfg3 = MCP_4MHz_20kBPS_CFG3 ; set = 1; break; case (CAN_500KBPS_10MHz) : cfg1 = 0x00; cfg2 = 0x92; cfg3 = 0x02; set = 1; break; default: set = 0; break; } if (set) { setRegister(MCP_CNF1, cfg1); setRegister(MCP_CNF2, cfg2); setRegister(MCP_CNF3, cfg3); return MCP2515_OK; } else { return MCP2515_FAIL; } } int mcp2515::configRate2(int bit_rate) { //struct spi_device *spi = to_spi_device(can->cdev.dev); //struct mcp251x *chip = dev_get_drvdata(&spi->dev); //struct mcp251x_platform_data *pdata = spi->dev.platform_data; printf("\n\rcanspeed=%d",bit_rate); int f_osc = 20000000; int tqs; /* tbit/TQ */ int brp; int ps1, ps2, propseg, sjw; /* Determine the BRP value that gives the requested bit rate. */ for(brp = 0; brp < 8; brp++) { tqs = f_osc / (2 * (brp + 1)) / bit_rate; if (tqs >= 5 && tqs <= 25 && (f_osc / (2 * (brp + 1)) / tqs) == bit_rate) break; } if (brp >= 8) printf("Spaztic BRP"); // return -1; /* The CAN bus bit time (tbit) is determined by: * tbit = (SyncSeg + PropSeg + PS1 + PS2) * TQ * with: * SyncSeg = 1 * sample point (between PS1 and PS2) must be at 60%-70% of the bit time * PropSeg + PS1 >= PS2 * PropSeg + PS1 >= Tdelay * PS2 > SJW * 1 <= PropSeg <= 8, 1 <= PS1 <=8, 2 <= PS2 <= 8 * SJW = 1 is sufficient in most cases. * Tdelay is usually 1 or 2 TQ. */ propseg = ps1 = ps2 = (tqs - 1) / 3; if (tqs - (1 + propseg + ps1 + ps2) == 2) ps1++; if (tqs - (1 + propseg + ps1 + ps2) == 1) ps2++; sjw = 1; printf("\n\rbit rate: BRP = %d, Tbit = %d TQ, PropSeg = %d, PS1 = %d, PS2 = %d, SJW = %d\n", brp, tqs, propseg, ps1, ps2, sjw); /* Since we can only change the bit rate when the network device is * down the chip must be in sleep mode. Wake it up and put it into * config mode. */ //mcp251x_hw_wakeup(spi); //mcp251x_write_bits(spi, CANCTRL, CANCTRL_REQOP_MASK, CANCTRL_REQOP_CONF); //mcp251x_write_reg(spi, CNF1, ((sjw-1) << 6) | brp); //mcp251x_write_reg(spi, CNF2, CNF2_BTLMODE | ((ps1-1) << 3) | (propseg-1)); //mcp251x_write_bits(spi, CNF3, CNF3_PHSEG2_MASK, (ps2-1)); setRegister(MCP_CNF1, ((sjw-1) << 6) | brp ); setRegister(MCP_CNF2, CNF2_BTLMODE | ((ps1-1) << 3) | (propseg-1) ); modifyRegister(MCP_CNF3, CNF3_PHSEG2_MASK, (ps2-1) ); //mcp251x_hw_sleep(spi); /* Calculate actual bit rate. */ //chip->bit_rate = pdata->f_osc / (2 * (brp + 1)) / tqs; return 0; } uint8_t mcp2515::readRegister( uint8_t address) { uint8_t ret; _select(); _spi_readwrite(MCP_READ); _spi_readwrite(address); ret = _spi_read(); _deselect(); return ret; } void mcp2515::readRegisterS( uint8_t address, uint8_t values[], uint8_t n) { uint8_t i; _select(); _spi_readwrite(MCP_READ); _spi_readwrite(address); // mcp2515 has auto-increment of address-pointer for (i=0; i<n; i++) { values[i] = _spi_read(); } _deselect(); } void mcp2515::modifyRegister( uint8_t address, uint8_t mask, uint8_t data) { _select(); _spi_readwrite(MCP_BITMOD); _spi_readwrite(address); _spi_readwrite(mask); _spi_readwrite(data); _deselect(); } uint8_t mcp2515::readXXStatus_helper( uint8_t cmd) { uint8_t i; _select(); _spi_readwrite(cmd); i = _spi_read(); _deselect(); return i; } uint8_t mcp2515::readStatus(void) { return readXXStatus_helper(MCP_READ_STATUS); } uint8_t mcp2515::RXStatus(void) { return readXXStatus_helper(MCP_RX_STATUS); } // read-modify-write - better: Bit Modify Instruction uint8_t mcp2515::setCANCTRL_Mode(uint8_t newmode) { uint8_t i; i = readRegister(MCP_CANCTRL); i &= ~(MODE_MASK); i |= newmode; setRegister(MCP_CANCTRL, i); // verify as advised in datasheet i = readRegister(MCP_CANCTRL); i &= MODE_MASK; if ( i == newmode ) { return MCP2515_OK; } else { return MCP2515_FAIL; } } void mcp2515::setRegisterS( uint8_t address, uint8_t values[], uint8_t n) { uint8_t i; _select(); _spi_readwrite(MCP_WRITE); _spi_readwrite(address); // mcp2515 has auto-increment of address-pointer for (i=0; i<n; i++) { _spi_readwrite(values[i]); } _deselect(); } void mcp2515::read_can_id( uint8_t mcp_addr, uint8_t* ext, uint32_t* can_id ) { uint8_t tbufdata[4]; *ext = 0; *can_id = 0; readRegisterS( mcp_addr, tbufdata, 4 ); *can_id = (tbufdata[MCP_SIDH]<<3) + (tbufdata[MCP_SIDL]>>5); if ( (tbufdata[MCP_SIDL] & MCP_TXB_EXIDE_M) == MCP_TXB_EXIDE_M ) { // extended id *can_id = (*can_id<<2) + (tbufdata[MCP_SIDL] & 0x03); *can_id <<= 16; *can_id = *can_id +(tbufdata[MCP_EID8]<<8) + tbufdata[MCP_EID0]; *ext = 1; } } void mcp2515::read_can_idN( uint8_t mcp_addr, CANFormat* ext, unsigned int* can_id ) { uint8_t tbufdata[4]; *ext = CANStandard; *can_id = 0; readRegisterS( mcp_addr, tbufdata, 4 ); *can_id = (tbufdata[MCP_SIDH]<<3) + (tbufdata[MCP_SIDL]>>5); if ( (tbufdata[MCP_SIDL] & MCP_TXB_EXIDE_M) == MCP_TXB_EXIDE_M ) { // extended id *can_id = (*can_id<<2) + (tbufdata[MCP_SIDL] & 0x03); *can_id <<= 16; *can_id = *can_id +(tbufdata[MCP_EID8]<<8) + tbufdata[MCP_EID0]; *ext = CANExtended;//1; } } // Buffer can be MCP_RXBUF_0 or MCP_RXBUF_1 void mcp2515::read_canMsg( uint8_t buffer_sidh_addr, CANMessage* msg) //CANMessage mcp2515::read_canMsg( uint8_t buffer_sidh_addr) { uint8_t mcp_addr, ctrl,dlc; mcp_addr = buffer_sidh_addr; read_can_idN( mcp_addr, &msg->format, &msg->id ); ctrl = readRegister( mcp_addr-1 ); dlc = readRegister( mcp_addr+4 ); //if ((*dlc & RTR_MASK) || (ctrl & 0x08)) { if ((ctrl & 0x08)) { msg->type = CANRemote; //1 CANRemote } else { msg->type = CANData; //0 CANData } dlc &= MCP_DLC_MASK; readRegisterS( mcp_addr+5, &(msg->data[0]), dlc ); msg->len =dlc; } void mcp2515::setDebugConsole(Serial c){ //console=c; debug=true; } void mcp2515::write_can_id( uint8_t mcp_addr, uint8_t ext, uint32_t can_id ) { uint16_t canid; uint8_t tbufdata[4]; canid = (uint16_t)(can_id & 0x0FFFF); if ( ext == 1) { tbufdata[MCP_EID0] = (uint8_t) (canid & 0xFF); tbufdata[MCP_EID8] = (uint8_t) (canid / 256); canid = (uint16_t)( can_id / 0x10000L ); tbufdata[MCP_SIDL] = (uint8_t) (canid & 0x03); tbufdata[MCP_SIDL] += (uint8_t) ((canid & 0x1C )*8); tbufdata[MCP_SIDL] |= MCP_TXB_EXIDE_M; tbufdata[MCP_SIDH] = (uint8_t) (canid / 32 ); } else { tbufdata[MCP_SIDH] = (uint8_t) (canid / 8 ); tbufdata[MCP_SIDL] = (uint8_t) ((canid & 0x07 )*32); tbufdata[MCP_EID0] = 0; tbufdata[MCP_EID8] = 0; } setRegisterS( mcp_addr, tbufdata, 4 ); } // Buffer can be MCP_TXBUF_0 MCP_TXBUF_1 or MCP_TXBUF_2 void mcp2515::write_canMsg( uint8_t buffer_sidh_addr, CANMessage* msg) { uint8_t mcp_addr, dlc; mcp_addr = buffer_sidh_addr; dlc = msg->len; setRegisterS(mcp_addr+5, &(msg->data[0]), dlc ); // write data bytes write_can_id( mcp_addr, msg->format, msg->id ); // write CAN id if ( msg->type == 1) dlc |= MCP_RTR_MASK; // if RTR set bit in byte setRegister( (mcp_addr+4), dlc ); // write the RTR and DLC } void mcp2515::start_transmit( uint8_t buffer_sidh_addr) { // TXBnCTRL_addr = TXBnSIDH_addr - 1 modifyRegister( buffer_sidh_addr-1 , MCP_TXB_TXREQ_M, MCP_TXB_TXREQ_M ); } uint8_t mcp2515::getNextFreeTXBuf(uint8_t *txbuf_n) { uint8_t res, i, ctrlval; uint8_t ctrlregs[MCP_N_TXBUFFERS] = { MCP_TXB0CTRL, MCP_TXB1CTRL, MCP_TXB2CTRL }; res = MCP_ALLTXBUSY; *txbuf_n = 0x00; // check all 3 TX-Buffers for (i=0; i<MCP_N_TXBUFFERS; i++) { ctrlval = readRegister( ctrlregs[i] ); if ( (ctrlval & MCP_TXB_TXREQ_M) == 0 ) { *txbuf_n = ctrlregs[i]+1; // return SIDH-address of Buffer res = MCP2515_OK; return res; /* ! function exit */ } } return res; } void mcp2515::initCANBuffers(void) { // uint8_t i, a1, a2, a3; // TODO: check why this is needed to receive extended // and standard frames // Mark all filter bits as don't care: write_can_id(MCP_RXM0SIDH, 0, 0); write_can_id(MCP_RXM1SIDH, 0, 0); // Anyway, set all filters to 0: write_can_id(MCP_RXF0SIDH, 1, 0); // RXB0: extended write_can_id(MCP_RXF1SIDH, 0, 0); // AND standard write_can_id(MCP_RXF2SIDH, 1, 0); // RXB1: extended write_can_id(MCP_RXF3SIDH, 0, 0); // AND standard write_can_id(MCP_RXF4SIDH, 0, 0); write_can_id(MCP_RXF5SIDH, 0, 0); /* // Clear, deactivate the three transmit buffers // TXBnCTRL -> TXBnD7 a1 = MCP_TXB0CTRL; a2 = MCP_TXB1CTRL; a3 = MCP_TXB2CTRL; for (i = 0; i < 14; i++) { // in-buffer loop setRegister(a1, 0); setRegister(a2, 0); setRegister(a3, 0); a1++; a2++; a3++; } */ // and clear, deactivate the two receive buffers. // setRegister(MCP_RXB0CTRL, 0); //setRegister(MCP_RXB1CTRL, 0); } uint8_t mcp2515::init(int canSpeed) { uint8_t res; _deselect(); //MCP_CS_DDR |= ( 1 << MCP_CS_BIT ); _reset(); res = setCANCTRL_Mode(MODE_CONFIG); if ( res == MCP2515_FAIL ) { printf("\r\nCAN init failed %d\n\r",&_ncs); return res; /* function exit on error */ } res = configRate2(canSpeed); //res = configRate(CAN_500KBPS_10MHz); if ( res == MCP2515_OK ) { initCANBuffers(); // enable both receive-buffers to receive messages // with std. and ext. identifiers // and enable rollover modifyRegister(MCP_RXB0CTRL, MCP_RXB_RX_MASK | MCP_RXB_BUKT_MASK, MCP_RXB_RX_STDEXT | MCP_RXB_BUKT_MASK ); modifyRegister(MCP_RXB1CTRL, MCP_RXB_RX_MASK, MCP_RXB_RX_STDEXT); // Prescaler setting of the CLKOUT pin to zero // => Spending clock frequency of the CLKOUT pin MCP2515 modifyRegister (MCP_CANCTRL, 0x07, CLKOUT_ENABLE); } return res; } /* * Select function */ void mcp2515::_select() { //printf("{"); _ncs = 0; } /* * Deselect function */ void mcp2515::_deselect() { _ncs = 1; //printf("}"); } int mcp2515::status() { int status = 0; _select(); spi.write(0xd7); status = (spi.write(0x00) << 8 ); status |= spi.write(0x00); _deselect(); return status; } void mcp2515::_pollbusy() { volatile int busy = 1; while (busy) { // if bit 7 is set, we can proceed if ( status() & 0x80 ) { busy = 0; } } } uint8_t mcp2515::_spi_readwrite(uint8_t data) { //printf("W0x%x ", data); uint8_t ret = spi.write(data); // printf("R0x%x,", ret); return ret; } uint8_t mcp2515::_spi_read(void) { return _spi_readwrite(SPI_NULL); } void mcp2515::dumpExtendedStatus(void) { uint8_t tec, rec, eflg; tec = readRegister(MCP_TEC); rec = readRegister(MCP_REC); eflg = readRegister(MCP_EFLG); printf("MCP2515 Extended Status:\n\r"); printf("MCP Transmit Error Count %d \r\n", tec); printf("MCP Receiver Error Count %d \n\r", rec); printf("MCP Error Flag %d\n\r", eflg); if ( (rec>127) || (tec>127) ) { printf("Error-Passive or Bus-Off\n\r"); } if (eflg & MCP_EFLG_RX1OVR) printf("Receive Buffer 1 Overflow\r\n"); if (eflg & MCP_EFLG_RX0OVR) printf("Receive Buffer 0 Overflow\n\r"); if (eflg & MCP_EFLG_TXBO) printf("Bus-Off\n\r"); if (eflg & MCP_EFLG_TXEP) printf("Receive Error Passive\n\r"); if (eflg & MCP_EFLG_TXWAR) printf("Transmit Error Warning\n\r"); if (eflg & MCP_EFLG_RXWAR) printf("Receive Error Warning\r\n"); if (eflg & MCP_EFLG_EWARN ) printf("Receive Error Warning\n\r"); }