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mcp_can.cpp
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mcp_can.cpp
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/*
mcp_can.cpp
2012 Copyright (c) Seeed Technology Inc. All right reserved.
Author:Loovee ([email protected])
2014-1-16
Contributor:
Cory J. Fowler
Latonita
Woodward1
Mehtajaghvi
BykeBlast
TheRo0T
Tsipizic
ralfEdmund
Nathancheek
BlueAndi
Adlerweb
Btetz
Hurvajs
xboxpro1
ttlappalainen
The MIT License (MIT)
Copyright (c) 2013 Seeed Technology Inc.
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
#include "mcp_can.h"
#define spi_readwrite pSPI->transfer
#define spi_read() spi_readwrite(0x00)
#define spi_write(spi_val) spi_readwrite(spi_val)
#define SPI_BEGIN() pSPI->beginTransaction(SPISettings(10000000, MSBFIRST, SPI_MODE0))
#define SPI_END() pSPI->endTransaction()
/*********************************************************************************************************
** Function name: txCtrlReg
** Descriptions: return tx ctrl reg according to tx buffer index.
** According to my tests this is faster and saves memory compared using vector
*********************************************************************************************************/
byte txCtrlReg(byte i) {
switch (i) {
case 0: return MCP_TXB0CTRL;
case 1: return MCP_TXB1CTRL;
case 2: return MCP_TXB2CTRL;
}
return MCP_TXB2CTRL;
}
/*********************************************************************************************************
** Function name: statusToBuffer
** Descriptions: converts CANINTF status to tx buffer index
*********************************************************************************************************/
byte statusToTxBuffer(byte status)
{
switch ( status ) {
case MCP_TX0IF : return 0;
case MCP_TX1IF : return 1;
case MCP_TX2IF : return 2;
}
return 0xff;
}
/*********************************************************************************************************
** Function name: statusToBuffer
** Descriptions: converts CANINTF status to tx buffer sidh
*********************************************************************************************************/
byte statusToTxSidh(byte status)
{
switch ( status ) {
case MCP_TX0IF : return MCP_TXB0SIDH;
case MCP_TX1IF : return MCP_TXB1SIDH;
case MCP_TX2IF : return MCP_TXB2SIDH;
}
return 0;
}
/*********************************************************************************************************
** Function name: txSidhToTxLoad
** Descriptions: return tx load command according to tx buffer sidh register
*********************************************************************************************************/
byte txSidhToRTS(byte sidh) {
switch (sidh) {
case MCP_TXB0SIDH: return MCP_RTS_TX0;
case MCP_TXB1SIDH: return MCP_RTS_TX1;
case MCP_TXB2SIDH: return MCP_RTS_TX2;
}
return 0;
}
/*********************************************************************************************************
** Function name: txSidhToTxLoad
** Descriptions: return tx load command according to tx buffer sidh register
*********************************************************************************************************/
byte txSidhToTxLoad(byte sidh) {
switch (sidh) {
case MCP_TXB0SIDH: return MCP_LOAD_TX0;
case MCP_TXB1SIDH: return MCP_LOAD_TX1;
case MCP_TXB2SIDH: return MCP_LOAD_TX2;
}
return 0;
}
/*********************************************************************************************************
** Function name: txIfFlag
** Descriptions: return tx interrupt flag
*********************************************************************************************************/
byte txIfFlag(byte i) {
switch (i) {
case 0: return MCP_TX0IF;
case 1: return MCP_TX1IF;
case 2: return MCP_TX2IF;
}
return 0;
}
/*********************************************************************************************************
** Function name: txStatusPendingFlag
** Descriptions: return buffer tx pending flag on status
*********************************************************************************************************/
byte txStatusPendingFlag(byte i) {
switch (i) {
case 0: return MCP_STAT_TX0_PENDING;
case 1: return MCP_STAT_TX1_PENDING;
case 2: return MCP_STAT_TX2_PENDING;
}
return 0xff;
}
/*********************************************************************************************************
** Function name: mcp2515_reset
** Descriptions: reset the device
*********************************************************************************************************/
void MCP_CAN::mcp2515_reset(void)
{
#ifdef SPI_HAS_TRANSACTION
SPI_BEGIN();
#endif
MCP2515_SELECT();
spi_readwrite(MCP_RESET);
MCP2515_UNSELECT();
#ifdef SPI_HAS_TRANSACTION
SPI_END();
#endif
delay(10);
}
/*********************************************************************************************************
** Function name: mcp2515_readRegister
** Descriptions: read register
*********************************************************************************************************/
byte MCP_CAN::mcp2515_readRegister(const byte address)
{
byte ret;
#ifdef SPI_HAS_TRANSACTION
SPI_BEGIN();
#endif
MCP2515_SELECT();
spi_readwrite(MCP_READ);
spi_readwrite(address);
ret = spi_read();
MCP2515_UNSELECT();
#ifdef SPI_HAS_TRANSACTION
SPI_END();
#endif
return ret;
}
/*********************************************************************************************************
** Function name: mcp2515_readRegisterS
** Descriptions: read registerS
*********************************************************************************************************/
void MCP_CAN::mcp2515_readRegisterS(const byte address, byte values[], const byte n)
{
byte i;
#ifdef SPI_HAS_TRANSACTION
SPI_BEGIN();
#endif
MCP2515_SELECT();
spi_readwrite(MCP_READ);
spi_readwrite(address);
// mcp2515 has auto-increment of address-pointer
for (i=0; i<n && i<CAN_MAX_CHAR_IN_MESSAGE; i++)
{
values[i] = spi_read();
}
MCP2515_UNSELECT();
#ifdef SPI_HAS_TRANSACTION
SPI_END();
#endif
}
/*********************************************************************************************************
** Function name: mcp2515_setRegister
** Descriptions: set register
*********************************************************************************************************/
void MCP_CAN::mcp2515_setRegister(const byte address, const byte value)
{
#ifdef SPI_HAS_TRANSACTION
SPI_BEGIN();
#endif
MCP2515_SELECT();
spi_readwrite(MCP_WRITE);
spi_readwrite(address);
spi_readwrite(value);
MCP2515_UNSELECT();
#ifdef SPI_HAS_TRANSACTION
SPI_END();
#endif
}
/*********************************************************************************************************
** Function name: mcp2515_setRegisterS
** Descriptions: set registerS
*********************************************************************************************************/
void MCP_CAN::mcp2515_setRegisterS(const byte address, const byte values[], const byte n)
{
byte i;
#ifdef SPI_HAS_TRANSACTION
SPI_BEGIN();
#endif
MCP2515_SELECT();
spi_readwrite(MCP_WRITE);
spi_readwrite(address);
for (i=0; i<n; i++)
{
spi_readwrite(values[i]);
}
MCP2515_UNSELECT();
#ifdef SPI_HAS_TRANSACTION
SPI_END();
#endif
}
/*********************************************************************************************************
** Function name: mcp2515_modifyRegister
** Descriptions: set bit of one register
*********************************************************************************************************/
void MCP_CAN::mcp2515_modifyRegister(const byte address, const byte mask, const byte data)
{
#ifdef SPI_HAS_TRANSACTION
SPI_BEGIN();
#endif
MCP2515_SELECT();
spi_readwrite(MCP_BITMOD);
spi_readwrite(address);
spi_readwrite(mask);
spi_readwrite(data);
MCP2515_UNSELECT();
#ifdef SPI_HAS_TRANSACTION
SPI_END();
#endif
}
/*********************************************************************************************************
** Function name: mcp2515_readStatus
** Descriptions: read mcp2515's Status
*********************************************************************************************************/
byte MCP_CAN::mcp2515_readStatus(void)
{
byte i;
#ifdef SPI_HAS_TRANSACTION
SPI_BEGIN();
#endif
MCP2515_SELECT();
spi_readwrite(MCP_READ_STATUS);
i = spi_read();
MCP2515_UNSELECT();
#ifdef SPI_HAS_TRANSACTION
SPI_END();
#endif
return i;
}
/*********************************************************************************************************
** Function name: setSleepWakeup
** Descriptions: Enable or disable the wake up interrupt (If disabled the MCP2515 will not be woken up by CAN bus activity)
*********************************************************************************************************/
void MCP_CAN::setSleepWakeup(const byte enable)
{
mcp2515_modifyRegister(MCP_CANINTE, MCP_WAKIF, enable ? MCP_WAKIF : 0);
}
/*********************************************************************************************************
** Function name: sleep
** Descriptions: Put mcp2515 in sleep mode to save power
*********************************************************************************************************/
byte MCP_CAN::sleep()
{
if(getMode() != MODE_SLEEP)
return mcp2515_setCANCTRL_Mode(MODE_SLEEP);
else
return CAN_OK;
}
/*********************************************************************************************************
** Function name: wake
** Descriptions: wake MCP2515 manually from sleep. It will come back in the mode it was before sleeping.
*********************************************************************************************************/
byte MCP_CAN::wake()
{
byte currMode = getMode();
if(currMode != mcpMode)
return mcp2515_setCANCTRL_Mode(mcpMode);
else
return CAN_OK;
}
/*********************************************************************************************************
** Function name: setMode
** Descriptions: Sets control mode
*********************************************************************************************************/
byte MCP_CAN::setMode(const byte opMode)
{
if(opMode != MODE_SLEEP) // if going to sleep, the value stored in opMode is not changed so that we can return to it later
mcpMode = opMode;
return mcp2515_setCANCTRL_Mode(opMode);
}
/*********************************************************************************************************
** Function name: getMode
** Descriptions: Returns current control mode
*********************************************************************************************************/
byte MCP_CAN::getMode()
{
return mcp2515_readRegister(MCP_CANSTAT) & MODE_MASK;
}
/*********************************************************************************************************
** Function name: mcp2515_setCANCTRL_Mode
** Descriptions: set control mode
*********************************************************************************************************/
byte MCP_CAN::mcp2515_setCANCTRL_Mode(const byte newmode)
{
// If the chip is asleep and we want to change mode then a manual wake needs to be done
// This is done by setting the wake up interrupt flag
// This undocumented trick was found at https://github.com/mkleemann/can/blob/master/can_sleep_mcp2515.c
if((getMode()) == MODE_SLEEP && newmode != MODE_SLEEP)
{
// Make sure wake interrupt is enabled
byte wakeIntEnabled = (mcp2515_readRegister(MCP_CANINTE) & MCP_WAKIF);
if(!wakeIntEnabled)
mcp2515_modifyRegister(MCP_CANINTE, MCP_WAKIF, MCP_WAKIF);
// Set wake flag (this does the actual waking up)
mcp2515_modifyRegister(MCP_CANINTF, MCP_WAKIF, MCP_WAKIF);
// Wait for the chip to exit SLEEP and enter LISTENONLY mode.
// If the chip is not connected to a CAN bus (or the bus has no other powered nodes) it will sometimes trigger the wake interrupt as soon
// as it's put to sleep, but it will stay in SLEEP mode instead of automatically switching to LISTENONLY mode.
// In this situation the mode needs to be manually set to LISTENONLY.
if(mcp2515_requestNewMode(MODE_LISTENONLY) != MCP2515_OK)
return MCP2515_FAIL;
// Turn wake interrupt back off if it was originally off
if(!wakeIntEnabled)
mcp2515_modifyRegister(MCP_CANINTE, MCP_WAKIF, 0);
}
// Clear wake flag
mcp2515_modifyRegister(MCP_CANINTF, MCP_WAKIF, 0);
return mcp2515_requestNewMode(newmode);
}
/*********************************************************************************************************
** Function name: mcp2515_requestNewMode
** Descriptions: Set control mode
*********************************************************************************************************/
byte MCP_CAN::mcp2515_requestNewMode(const byte newmode)
{
unsigned long startTime = millis();
// Spam new mode request and wait for the operation to complete
while(1)
{
// Request new mode
// This is inside the loop as sometimes requesting the new mode once doesn't work (usually when attempting to sleep)
mcp2515_modifyRegister(MCP_CANCTRL, MODE_MASK, newmode);
byte statReg = mcp2515_readRegister(MCP_CANSTAT);
if((statReg & MODE_MASK) == newmode) // We're now in the new mode
return MCP2515_OK;
else if((millis() - startTime) > 200) // Wait no more than 200ms for the operation to complete
return MCP2515_FAIL;
}
}
/*********************************************************************************************************
** Function name: mcp2515_configRate
** Descriptions: set baudrate
*********************************************************************************************************/
byte MCP_CAN::mcp2515_configRate(const byte canSpeed, const byte clock)
{
byte set, cfg1, cfg2, cfg3;
set = 1;
switch (clock)
{
case (MCP_16MHz) :
switch (canSpeed)
{
case (CAN_5KBPS):
cfg1 = MCP_16MHz_5kBPS_CFG1;
cfg2 = MCP_16MHz_5kBPS_CFG2;
cfg3 = MCP_16MHz_5kBPS_CFG3;
break;
case (CAN_10KBPS):
cfg1 = MCP_16MHz_10kBPS_CFG1;
cfg2 = MCP_16MHz_10kBPS_CFG2;
cfg3 = MCP_16MHz_10kBPS_CFG3;
break;
case (CAN_20KBPS):
cfg1 = MCP_16MHz_20kBPS_CFG1;
cfg2 = MCP_16MHz_20kBPS_CFG2;
cfg3 = MCP_16MHz_20kBPS_CFG3;
break;
case (CAN_25KBPS):
cfg1 = MCP_16MHz_25kBPS_CFG1;
cfg2 = MCP_16MHz_25kBPS_CFG2;
cfg3 = MCP_16MHz_25kBPS_CFG3;
break;
case (CAN_31K25BPS):
cfg1 = MCP_16MHz_31k25BPS_CFG1;
cfg2 = MCP_16MHz_31k25BPS_CFG2;
cfg3 = MCP_16MHz_31k25BPS_CFG3;
break;
case (CAN_33KBPS):
cfg1 = MCP_16MHz_33kBPS_CFG1;
cfg2 = MCP_16MHz_33kBPS_CFG2;
cfg3 = MCP_16MHz_33kBPS_CFG3;
break;
case (CAN_40KBPS):
cfg1 = MCP_16MHz_40kBPS_CFG1;
cfg2 = MCP_16MHz_40kBPS_CFG2;
cfg3 = MCP_16MHz_40kBPS_CFG3;
break;
case (CAN_50KBPS):
cfg1 = MCP_16MHz_50kBPS_CFG1;
cfg2 = MCP_16MHz_50kBPS_CFG2;
cfg3 = MCP_16MHz_50kBPS_CFG3;
break;
case (CAN_80KBPS):
cfg1 = MCP_16MHz_80kBPS_CFG1;
cfg2 = MCP_16MHz_80kBPS_CFG2;
cfg3 = MCP_16MHz_80kBPS_CFG3;
break;
case (CAN_83K3BPS):
cfg1 = MCP_16MHz_83k3BPS_CFG1;
cfg2 = MCP_16MHz_83k3BPS_CFG2;
cfg3 = MCP_16MHz_83k3BPS_CFG3;
break;
case (CAN_95KBPS):
cfg1 = MCP_16MHz_95kBPS_CFG1;
cfg2 = MCP_16MHz_95kBPS_CFG2;
cfg3 = MCP_16MHz_95kBPS_CFG3;
break;
case (CAN_100KBPS):
cfg1 = MCP_16MHz_100kBPS_CFG1;
cfg2 = MCP_16MHz_100kBPS_CFG2;
cfg3 = MCP_16MHz_100kBPS_CFG3;
break;
case (CAN_125KBPS):
cfg1 = MCP_16MHz_125kBPS_CFG1;
cfg2 = MCP_16MHz_125kBPS_CFG2;
cfg3 = MCP_16MHz_125kBPS_CFG3;
break;
case (CAN_200KBPS):
cfg1 = MCP_16MHz_200kBPS_CFG1;
cfg2 = MCP_16MHz_200kBPS_CFG2;
cfg3 = MCP_16MHz_200kBPS_CFG3;
break;
case (CAN_250KBPS):
cfg1 = MCP_16MHz_250kBPS_CFG1;
cfg2 = MCP_16MHz_250kBPS_CFG2;
cfg3 = MCP_16MHz_250kBPS_CFG3;
break;
case (CAN_500KBPS):
cfg1 = MCP_16MHz_500kBPS_CFG1;
cfg2 = MCP_16MHz_500kBPS_CFG2;
cfg3 = MCP_16MHz_500kBPS_CFG3;
break;
case (CAN_666KBPS):
cfg1 = MCP_16MHz_666kBPS_CFG1;
cfg2 = MCP_16MHz_666kBPS_CFG2;
cfg3 = MCP_16MHz_666kBPS_CFG3;
break;
case (CAN_1000KBPS):
cfg1 = MCP_16MHz_1000kBPS_CFG1;
cfg2 = MCP_16MHz_1000kBPS_CFG2;
cfg3 = MCP_16MHz_1000kBPS_CFG3;
break;
default:
set = 0;
break;
}
break;
case (MCP_8MHz) :
switch (canSpeed)
{
case (CAN_5KBPS) :
cfg1 = MCP_8MHz_5kBPS_CFG1;
cfg2 = MCP_8MHz_5kBPS_CFG2;
cfg3 = MCP_8MHz_5kBPS_CFG3;
break;
case (CAN_10KBPS) :
cfg1 = MCP_8MHz_10kBPS_CFG1;
cfg2 = MCP_8MHz_10kBPS_CFG2;
cfg3 = MCP_8MHz_10kBPS_CFG3;
break;
case (CAN_20KBPS) :
cfg1 = MCP_8MHz_20kBPS_CFG1;
cfg2 = MCP_8MHz_20kBPS_CFG2;
cfg3 = MCP_8MHz_20kBPS_CFG3;
break;
case (CAN_31K25BPS) :
cfg1 = MCP_8MHz_31k25BPS_CFG1;
cfg2 = MCP_8MHz_31k25BPS_CFG2;
cfg3 = MCP_8MHz_31k25BPS_CFG3;
break;
case (CAN_40KBPS) :
cfg1 = MCP_8MHz_40kBPS_CFG1;
cfg2 = MCP_8MHz_40kBPS_CFG2;
cfg3 = MCP_8MHz_40kBPS_CFG3;
break;
case (CAN_50KBPS) :
cfg1 = MCP_8MHz_50kBPS_CFG1;
cfg2 = MCP_8MHz_50kBPS_CFG2;
cfg3 = MCP_8MHz_50kBPS_CFG3;
break;
case (CAN_80KBPS) :
cfg1 = MCP_8MHz_80kBPS_CFG1;
cfg2 = MCP_8MHz_80kBPS_CFG2;
cfg3 = MCP_8MHz_80kBPS_CFG3;
break;
case (CAN_100KBPS) :
cfg1 = MCP_8MHz_100kBPS_CFG1;
cfg2 = MCP_8MHz_100kBPS_CFG2;
cfg3 = MCP_8MHz_100kBPS_CFG3;
break;
case (CAN_125KBPS) :
cfg1 = MCP_8MHz_125kBPS_CFG1;
cfg2 = MCP_8MHz_125kBPS_CFG2;
cfg3 = MCP_8MHz_125kBPS_CFG3;
break;
case (CAN_200KBPS) :
cfg1 = MCP_8MHz_200kBPS_CFG1;
cfg2 = MCP_8MHz_200kBPS_CFG2;
cfg3 = MCP_8MHz_200kBPS_CFG3;
break;
case (CAN_250KBPS) :
cfg1 = MCP_8MHz_250kBPS_CFG1;
cfg2 = MCP_8MHz_250kBPS_CFG2;
cfg3 = MCP_8MHz_250kBPS_CFG3;
break;
case (CAN_500KBPS) :
cfg1 = MCP_8MHz_500kBPS_CFG1;
cfg2 = MCP_8MHz_500kBPS_CFG2;
cfg3 = MCP_8MHz_500kBPS_CFG3;
break;
case (CAN_1000KBPS) :
cfg1 = MCP_8MHz_1000kBPS_CFG1;
cfg2 = MCP_8MHz_1000kBPS_CFG2;
cfg3 = MCP_8MHz_1000kBPS_CFG3;
break;
default:
set = 0;
break;
}
break;
default:
set = 0;
break;
}
if (set) {
mcp2515_setRegister(MCP_CNF1, cfg1);
mcp2515_setRegister(MCP_CNF2, cfg2);
mcp2515_setRegister(MCP_CNF3, cfg3);
return MCP2515_OK;
}
else {
return MCP2515_FAIL;
}
}
/*********************************************************************************************************
** Function name: mcp2515_initCANBuffers
** Descriptions: init canbuffers
*********************************************************************************************************/
void MCP_CAN::mcp2515_initCANBuffers(void)
{
byte i, a1, a2, a3;
a1 = MCP_TXB0CTRL;
a2 = MCP_TXB1CTRL;
a3 = MCP_TXB2CTRL;
for (i = 0; i < 14; i++) // in-buffer loop
{
mcp2515_setRegister(a1, 0);
mcp2515_setRegister(a2, 0);
mcp2515_setRegister(a3, 0);
a1++;
a2++;
a3++;
}
mcp2515_setRegister(MCP_RXB0CTRL, 0);
mcp2515_setRegister(MCP_RXB1CTRL, 0);
}
/*********************************************************************************************************
** Function name: mcp2515_init
** Descriptions: init the device
*********************************************************************************************************/
byte MCP_CAN::mcp2515_init(const byte canSpeed, const byte clock)
{
byte res;
mcp2515_reset();
res = mcp2515_setCANCTRL_Mode(MODE_CONFIG);
if (res > 0)
{
#if DEBUG_EN
Serial.print("Enter setting mode fail\r\n");
#else
delay(10);
#endif
return res;
}
#if DEBUG_EN
Serial.print("Enter setting mode success \r\n");
#else
delay(10);
#endif
// set boadrate
if (mcp2515_configRate(canSpeed, clock))
{
#if DEBUG_EN
Serial.print("set rate fall!!\r\n");
#else
delay(10);
#endif
return res;
}
#if DEBUG_EN
Serial.print("set rate success!!\r\n");
#else
delay(10);
#endif
if ( res == MCP2515_OK ) {
// init canbuffers
mcp2515_initCANBuffers();
// interrupt mode
mcp2515_setRegister(MCP_CANINTE, MCP_RX0IF | MCP_RX1IF);
#if (DEBUG_RXANY==1)
// enable both receive-buffers to receive any message and enable rollover
mcp2515_modifyRegister(MCP_RXB0CTRL,
MCP_RXB_RX_MASK | MCP_RXB_BUKT_MASK,
MCP_RXB_RX_ANY | MCP_RXB_BUKT_MASK);
mcp2515_modifyRegister(MCP_RXB1CTRL, MCP_RXB_RX_MASK,
MCP_RXB_RX_ANY);
#else
// enable both receive-buffers to receive messages with std. and ext. identifiers and enable rollover
mcp2515_modifyRegister(MCP_RXB0CTRL,
MCP_RXB_RX_MASK | MCP_RXB_BUKT_MASK,
MCP_RXB_RX_STDEXT | MCP_RXB_BUKT_MASK);
mcp2515_modifyRegister(MCP_RXB1CTRL, MCP_RXB_RX_MASK,
MCP_RXB_RX_STDEXT);
#endif
// enter normal mode
res = setMode(MODE_NORMAL);
if (res)
{
#if DEBUG_EN
Serial.print("Enter Normal Mode Fail!!\r\n");
#else
delay(10);
#endif
return res;
}
#if DEBUG_EN
Serial.print("Enter Normal Mode Success!!\r\n");
#else
delay(10);
#endif
}
return res;
}
/*********************************************************************************************************
** Function name: mcp2515_id_to_buf
** Descriptions: configure tbufdata[4] from id and ext
*********************************************************************************************************/
void mcp2515_id_to_buf(const byte ext, const unsigned long id, byte *tbufdata)
{
uint16_t canid;
canid = (uint16_t)(id & 0x0FFFF);
if ( ext == 1)
{
tbufdata[MCP_EID0] = (byte) (canid & 0xFF);
tbufdata[MCP_EID8] = (byte) (canid >> 8);
canid = (uint16_t)(id >> 16);
tbufdata[MCP_SIDL] = (byte) (canid & 0x03);
tbufdata[MCP_SIDL] += (byte) ((canid & 0x1C) << 3);
tbufdata[MCP_SIDL] |= MCP_TXB_EXIDE_M;
tbufdata[MCP_SIDH] = (byte) (canid >> 5 );
}
else
{
tbufdata[MCP_SIDH] = (byte) (canid >> 3 );
tbufdata[MCP_SIDL] = (byte) ((canid & 0x07 ) << 5);
tbufdata[MCP_EID0] = 0;
tbufdata[MCP_EID8] = 0;
}
}
/*********************************************************************************************************
** Function name: mcp2515_write_id
** Descriptions: write can id
*********************************************************************************************************/
void MCP_CAN::mcp2515_write_id(const byte mcp_addr, const byte ext, const unsigned long id)
{
byte tbufdata[4];
mcp2515_id_to_buf(ext,id,tbufdata);
mcp2515_setRegisterS(mcp_addr, tbufdata, 4);
}
/*********************************************************************************************************
** Function name: mcp2515_read_id
** Descriptions: read can id
*********************************************************************************************************/
void MCP_CAN::mcp2515_read_id(const byte mcp_addr, byte* ext, unsigned long* id)
{
byte tbufdata[4];
*ext = 0;
*id = 0;
mcp2515_readRegisterS(mcp_addr, tbufdata, 4);
*id = (tbufdata[MCP_SIDH] << 3) + (tbufdata[MCP_SIDL] >> 5);
if ( (tbufdata[MCP_SIDL] & MCP_TXB_EXIDE_M) == MCP_TXB_EXIDE_M )
{
// extended id
*id = (*id << 2) + (tbufdata[MCP_SIDL] & 0x03);
*id = (*id << 8) + tbufdata[MCP_EID8];
*id = (*id << 8) + tbufdata[MCP_EID0];
*ext = 1;
}
}
/*********************************************************************************************************
** Function name: mcp2515_write_canMsg
** Descriptions: write msg
** Note! There is no check for right address!
*********************************************************************************************************/
void MCP_CAN::mcp2515_write_canMsg(const byte buffer_sidh_addr, unsigned long id, byte ext, byte rtrBit, byte len, volatile const byte *buf)
{
byte load_addr=txSidhToTxLoad(buffer_sidh_addr);
byte tbufdata[4];
byte dlc = len | ( rtrBit ? MCP_RTR_MASK : 0 ) ;
byte i;
mcp2515_id_to_buf(ext,id,tbufdata);
#ifdef SPI_HAS_TRANSACTION
SPI_BEGIN();
#endif
MCP2515_SELECT();
spi_readwrite(load_addr);
for (i = 0; i < 4; i++) spi_write(tbufdata[i]);
spi_write(dlc);
for (i = 0; i < len && i<CAN_MAX_CHAR_IN_MESSAGE; i++) spi_write(buf[i]);
MCP2515_UNSELECT();
#ifdef SPI_HAS_TRANSACTION
SPI_END();
#endif
mcp2515_start_transmit( buffer_sidh_addr );
}
/*********************************************************************************************************
** Function name: mcp2515_read_canMsg
** Descriptions: read message
*********************************************************************************************************/
void MCP_CAN::mcp2515_read_canMsg( const byte buffer_load_addr, volatile unsigned long *id, volatile byte *ext, volatile byte *rtrBit, volatile byte *len, volatile byte *buf) /* read can msg */
{
byte tbufdata[4];
byte i;
MCP2515_SELECT();
spi_readwrite(buffer_load_addr);
// mcp2515 has auto-increment of address-pointer
for (i = 0; i < 4; i++) tbufdata[i] = spi_read();
*id = (tbufdata[MCP_SIDH] << 3) + (tbufdata[MCP_SIDL] >> 5);
*ext = 0;
if ( (tbufdata[MCP_SIDL] & MCP_TXB_EXIDE_M) == MCP_TXB_EXIDE_M )
{
/* extended id */
*id = (*id << 2) + (tbufdata[MCP_SIDL] & 0x03);
*id = (*id << 8) + tbufdata[MCP_EID8];
*id = (*id << 8) + tbufdata[MCP_EID0];
*ext = 1;
}
byte pMsgSize = spi_read();
*len = pMsgSize & MCP_DLC_MASK;
*rtrBit = (pMsgSize & MCP_RTR_MASK) ? 1 : 0;
for (i = 0; i < *len && i<CAN_MAX_CHAR_IN_MESSAGE; i++) {
buf[i] = spi_read();
}
MCP2515_UNSELECT();
}
/*********************************************************************************************************
** Function name: mcp2515_start_transmit
** Descriptions: Start message transmit on mcp2515
*********************************************************************************************************/
void MCP_CAN::mcp2515_start_transmit(const byte mcp_addr) // start transmit
{
#ifdef SPI_HAS_TRANSACTION
SPI_BEGIN();
#endif
MCP2515_SELECT();
spi_readwrite(txSidhToRTS(mcp_addr));
MCP2515_UNSELECT();
#ifdef SPI_HAS_TRANSACTION
SPI_END();
#endif
}
/*********************************************************************************************************
** Function name: mcp2515_isTXBufFree
** Descriptions: Test is tx buffer free for transmitting
*********************************************************************************************************/
byte MCP_CAN::mcp2515_isTXBufFree(byte *txbuf_n, byte iBuf) /* get Next free txbuf */
{
*txbuf_n = 0x00;
if ( iBuf>=MCP_N_TXBUFFERS ||
(mcp2515_readStatus() & txStatusPendingFlag(iBuf))!=0 ) return MCP_ALLTXBUSY;
*txbuf_n = txCtrlReg(iBuf) + 1; /* return SIDH-address of Buffer */
mcp2515_modifyRegister(MCP_CANINTF, txIfFlag(iBuf), 0);
return MCP2515_OK;
}
/*********************************************************************************************************
** Function name: mcp2515_getNextFreeTXBuf
** Descriptions: finds next free tx buffer for sending. Return MCP_ALLTXBUSY, if there is none.
*********************************************************************************************************/
byte MCP_CAN::mcp2515_getNextFreeTXBuf(byte *txbuf_n) // get Next free txbuf
{
byte status=mcp2515_readStatus() & MCP_STAT_TX_PENDING_MASK;
byte i;
*txbuf_n = 0x00;
if ( status==MCP_STAT_TX_PENDING_MASK ) return MCP_ALLTXBUSY; // All buffers are pending
// check all 3 TX-Buffers except reserved
for (i = 0; i < MCP_N_TXBUFFERS-nReservedTx; i++)
{
if ( (status & txStatusPendingFlag(i) ) == 0 ) {
*txbuf_n = txCtrlReg(i) + 1; // return SIDH-address of Buffer
mcp2515_modifyRegister(MCP_CANINTF, txIfFlag(i), 0);
return MCP2515_OK; // ! function exit
}
}
return MCP_ALLTXBUSY;
}
/*********************************************************************************************************
** Function name: MCP_CAN
** Descriptions: Constructor
*********************************************************************************************************/
MCP_CAN::MCP_CAN(byte _CS) : nReservedTx(0)
{
pSPI=&SPI; init_CS(_CS);
}
/*********************************************************************************************************
** Function name: init_CS
** Descriptions: init CS pin and set UNSELECTED
*********************************************************************************************************/
void MCP_CAN::init_CS(byte _CS)
{
if (_CS == 0) return;
SPICS = _CS;
pinMode(SPICS, OUTPUT);
MCP2515_UNSELECT();
}
/*********************************************************************************************************
** Function name: begin
** Descriptions: init can and set speed
*********************************************************************************************************/
byte MCP_CAN::begin(byte speedset, const byte clockset)
{
pSPI->begin();
byte res = mcp2515_init(speedset, clockset);
return ((res == MCP2515_OK) ? CAN_OK : CAN_FAILINIT);
}
/*********************************************************************************************************
** Function name: enableTxInterrupt
** Descriptions: enable interrupt for all tx buffers
*********************************************************************************************************/
void MCP_CAN::enableTxInterrupt(bool enable)
{
byte interruptStatus=mcp2515_readRegister(MCP_CANINTE);
if ( enable ) {
interruptStatus |= MCP_TX_INT;
} else {
interruptStatus &= ~MCP_TX_INT;
}