Diff: MCP2515.cpp

Revision:

0:b65cb1bbf0ce

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MCP2515.cpp	Fri Jan 18 17:00:28 2013 +0000
@@ -0,0 +1,474 @@
+
+#include "MCP2515.h"
+
+MCP2515::MCP2515(SPI& spi, PinName cs) : spi(spi), cs(cs)
+{
+    /*
+    reset = 0; // RESET MCP2515 CONTROLLER
+    wait_ms(10);
+    reset = 1;
+    wait_ms(100);
+    */
+}
+
+void MCP2515::baudConfig(int bitRate)//sets bitrate for MCP2515 node
+{
+    byte config0 = 0x00;
+    byte config1 = 0x00;
+    byte config2 = 0x00;
+
+    switch (bitRate)
+    {
+case 10:
+        config0 = 0x31;
+        config1 = 0xB8;
+        config2 = 0x05;
+        break;
+
+case 20:
+        config0 = 0x18;
+        config1 = 0xB8;
+        config2 = 0x05;
+        break;
+
+case 50:
+        config0 = 0x09;
+        config1 = 0xB8;
+        config2 = 0x05;
+        break;
+
+case 100:
+        config0 = 0x04;
+        config1 = 0xB8;
+        config2 = 0x05;
+        break;
+
+case 125:
+        config0 = 0x03;
+        config1 = 0xB8;
+        config2 = 0x05;
+        break;
+
+case 250:
+        config0 = 0x01;
+        config1 = 0xB8;
+        config2 = 0x05;
+        break;
+
+case 500:
+        config0 = 0x00;
+        config1 = 0xB8;
+        config2 = 0x05;
+        break;
+case 1000:
+    //1 megabit mode added by Patrick Cruce(pcruce_at_igpp.ucla.edu)
+    //Faster communications enabled by shortening bit timing phases(3 Tq. PS1 & 3 Tq. PS2) Note that this may exacerbate errors due to synchronization or arbitration.
+    config0 = 0x80;
+    config1 = 0x90;
+    config2 = 0x02;
+    }
+    cs = 0;
+    wait_ms(10);
+    spi.write(WRITE);
+    spi.write(CNF0);
+    spi.write(config0);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+
+    cs = 0;
+    wait_ms(10);
+    spi.write(WRITE);
+    spi.write(CNF1);
+    spi.write(config1);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+
+    cs = 0;
+    wait_ms(10);
+    spi.write(WRITE);
+    spi.write(CNF2);
+    spi.write(config2);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+}
+
+//Method added to enable testing in loopback mode.(pcruce_at_igpp.ucla.edu)
+void MCP2515::setMode(MCP2515Mode mode) { //put MCP2515 controller in one of five modes
+
+    //byte writeVal,mask,readVal;
+    byte writeVal = 0x00;
+    byte mask = 0x00;
+
+    switch(mode) {
+      case CONFIGURATION:
+            writeVal = 0x80;
+            break;
+      case NORMAL:
+          writeVal = 0x00;
+            break;
+      case SLEEP:
+            writeVal = 0x20;
+          break;
+    case LISTEN:
+            writeVal = 0x60;
+          break;
+      case LOOPBACK:
+            writeVal = 0x40;
+          break;
+   }
+
+    mask = 0xE0;
+
+    cs = 0;
+    spi.write(BIT_MODIFY);
+    spi.write(MCP2515CTRL);
+    spi.write(mask);
+    spi.write(writeVal);
+    cs = 1;
+
+}
+
+
+void MCP2515::send_0()//transmits buffer 0
+{
+
+    //wait_mss removed from SEND command(pcruce_at_igpp.ucla.edu)
+    //In testing we found that any lost data was from PC<->Serial wait_mss,
+    //Not MCP2515 Controller/AVR wait_mss.  Thus removing the wait_mss at this level
+    //allows maximum flexibility and performance.
+    cs = 0;
+    spi.write(SEND_TX_BUF_0);
+    cs = 1;
+}
+
+void MCP2515::send_1()//transmits buffer 1
+{
+    cs = 0;
+    spi.write(SEND_TX_BUF_1);
+    cs = 1;
+}
+
+void MCP2515::send_2()//transmits buffer 2
+{
+    cs = 0;
+    spi.write(SEND_TX_BUF_2);
+    cs = 1;
+}
+
+char MCP2515::readID_0()//reads ID in recieve buffer 0
+{
+    char retVal;
+    cs = 0;
+    wait_ms(10);
+    spi.write(READ_RX_BUF_0_ID);
+    retVal = spi.write(0xFF);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+    return retVal;
+}
+
+char MCP2515::readID_1()//reads ID in reciever buffer 1
+{
+    char retVal;
+    cs = 0;
+    wait_ms(10);
+    spi.write(READ_RX_BUF_1_ID);
+    retVal = spi.write(0xFF);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+    return retVal;
+}
+
+char MCP2515::readDATA_0()//reads DATA in recieve buffer 0
+{
+    char retVal;
+    cs = 0;
+    wait_ms(10);
+    spi.write( READ_RX_BUF_0_DATA);
+    retVal = spi.write(0xFF);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+    return retVal;
+}
+
+char MCP2515::readDATA_1()//reads data in recieve buffer 1
+{
+    char retVal;
+    cs = 0;
+    wait_ms(10);
+    spi.write( READ_RX_BUF_1_DATA);
+    retVal = spi.write(0xFF);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+    return retVal;
+}
+
+    //extending MCP2515 data read to full frames(pcruce_at_igpp.ucla.edu)
+    //It is the responsibility of the user to allocate memory for output.
+    //If you don't know what length the bus frames will be, data_out should be 8-bytes
+void MCP2515::readDATA_ff_0(byte* length_out,byte *data_out,unsigned short *id_out){
+
+    byte len,i;
+    unsigned short id_h,id_l;
+
+    cs = 0;
+    spi.write(READ_RX_BUF_0_ID);
+    id_h = (unsigned short) spi.write(0xFF); //id high
+    id_l = (unsigned short) spi.write(0xFF); //id low
+    spi.write(0xFF); //extended id high(unused)
+    spi.write(0xFF); //extended id low(unused)
+    len = (spi.write(0xFF) & 0x0F); //data length code
+    for (i = 0;i<len;i++) {
+        data_out[i] = spi.write(0xFF);
+    }
+    cs = 1;
+    (*length_out) = len;
+    (*id_out) = ((id_h << 3) + ((id_l & 0xE0) >> 5)); //repack identifier
+    
+}
+
+void MCP2515::readDATA_ff_1(byte* length_out,byte *data_out,unsigned short *id_out){
+
+    byte id_h,id_l,len,i;
+
+    cs = 0;
+    spi.write(READ_RX_BUF_1_ID);
+    id_h = spi.write(0xFF); //id high
+    id_l = spi.write(0xFF); //id low
+    spi.write(0xFF); //extended id high(unused)
+    spi.write(0xFF); //extended id low(unused)
+    len = (spi.write(0xFF) & 0x0F); //data length code
+    for (i = 0;i<len;i++) {
+        data_out[i] = spi.write(0xFF);
+    }
+    cs = 1;
+
+    (*length_out) = len;
+    (*id_out) = ((((unsigned short) id_h) << 3) + ((id_l & 0xE0) >> 5)); //repack identifier
+}
+
+    //Adding method to read status register
+    //MCP2515 be used to determine whether a frame was received.
+    //(readStatus() & 0x80) == 0x80 means frame in buffer 0
+    //(readStatus() & 0x40) == 0x40 means frame in buffer 1
+byte MCP2515::readStatus() 
+{
+    byte retVal;
+    cs = 0;
+    spi.write(READ_STATUS);
+    retVal = spi.write(0xFF);
+    cs = 1;
+    return retVal;
+
+}
+
+void MCP2515::load_0(byte identifier, byte data)//loads ID and DATA into transmit buffer 0
+{
+    cs = 0;
+    wait_ms(10);
+    spi.write(LOAD_TX_BUF_0_ID);
+    spi.write(identifier);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+
+    cs = 0;
+    wait_ms(10);
+    spi.write(LOAD_TX_BUF_0_DATA);
+    spi.write(data);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+}
+
+void MCP2515::load_1(byte identifier, byte data)//loads ID and DATA into transmit buffer 1
+{
+    cs = 0;
+    wait_ms(10);
+    spi.write(LOAD_TX_BUF_1_ID);
+    spi.write(identifier);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+
+    cs = 0;
+    wait_ms(10);
+    spi.write(LOAD_TX_BUF_1_DATA);
+    spi.write(data);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+}
+
+void MCP2515::load_2(byte identifier, byte data)//loads ID and DATA into transmit buffer 2
+{
+    cs = 0;
+    wait_ms(10);
+    spi.write(LOAD_TX_BUF_2_ID);
+    spi.write(identifier);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+
+    cs = 0;
+    wait_ms(10);
+    spi.write(LOAD_TX_BUF_2_DATA);
+    spi.write(data);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+}
+
+void MCP2515::load_ff_0(byte length,unsigned short identifier,byte *data)
+{
+    
+    byte i,id_high,id_low;
+
+    //generate id bytes before spi write
+    id_high = (byte) (identifier >> 3);
+    id_low = (byte) ((identifier << 5) & 0x00E0);
+
+    cs = 0;
+    spi.write(LOAD_TX_BUF_0_ID);
+    spi.write(id_high); //identifier high bits
+    spi.write(id_low); //identifier low bits
+    spi.write(0x00); //extended identifier registers(unused)
+    spi.write(0x00);
+    spi.write(length);
+    for (i=0;i<length;i++) { //load data buffer
+        spi.write(data[i]);
+    }
+
+    cs = 1;
+
+}
+
+void MCP2515::load_ff_1(byte length,unsigned short identifier,byte *data)
+{
+    
+    byte i,id_high,id_low;
+
+    //generate id bytes before spi write
+    id_high = (byte) (identifier >> 3);
+    id_low = (byte) ((identifier << 5) & 0x00E0);
+
+    cs = 0;
+    spi.write(LOAD_TX_BUF_1_ID);
+    spi.write(id_high); //identifier high bits
+    spi.write(id_low); //identifier low bits
+    spi.write(0x00); //extended identifier registers(unused)
+    spi.write(0x00);
+    spi.write(length);
+    for (i=0;i<length;i++) { //load data buffer
+        spi.write(data[i]);
+    }
+
+    cs = 1;
+
+
+}
+
+void MCP2515::load_ff_2(byte length,unsigned short identifier,byte *data)
+{
+    
+    byte i,id_high,id_low;
+
+    //generate id bytes before spi write
+    id_high = (byte) (identifier >> 3);
+    id_low = (byte) ((identifier << 5) & 0x00E0);
+
+    cs = 0;
+
+    spi.write(LOAD_TX_BUF_2_ID);
+    spi.write(id_high); //identifier high bits
+    spi.write(id_low); //identifier low bits
+    spi.write(0x00); //extended identifier registers(unused)
+    spi.write(0x00);
+    spi.write(length); //data length code
+    for (i=0;i<length;i++) { //load data buffer
+        spi.write(data[i]);
+    }
+
+    cs = 1;
+
+}
+
+//------------------------------------------------------------------------------
+//Added for ram
+void MCP2515::writeRegister(byte address, byte data)
+{
+    cs = 0;
+    wait_ms(10);
+    spi.write(WRITE);
+    spi.write(address);
+    spi.write(data);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+}
+void MCP2515::readRegister(byte address, byte *data_out)
+{
+    cs = 0;
+    wait_ms(10);
+    spi.write(READ);
+    spi.write(address);
+    *data_out = spi.write(0xFF);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+}
+
+void MCP2515::reset()
+{
+    cs = 0;
+    wait_ms(10);
+    spi.write(RESET_REG);
+    wait_ms(10);
+    cs = 1;
+    wait_ms(10);
+}
+
+byte MCP2515::readRXStatus()
+{
+    byte retVal;
+    cs = 0;
+    spi.write(RX_STATUS);
+    retVal = spi.write(0xFF);
+    cs = 1;
+    return retVal;
+}
+
+void MCP2515::bitModify(byte address, byte mask, byte data)
+{
+    cs = 0;
+    spi.write(BIT_MODIFY);
+    spi.write(address);
+    spi.write(mask);
+    spi.write(data);
+    cs = 1;
+}
+
+void MCP2515::setMask(unsigned short identifier)
+{
+    setMask_0(identifier);
+    setMask_1(identifier);
+}
+
+void MCP2515::setMask_0(unsigned short identifier)
+{
+    writeRegister(RXM0SIDH, (byte)(identifier>>3));
+    writeRegister(RXM0SIDL, (byte)(identifier<<5));
+}
+
+void MCP2515::setMask_1(unsigned short identifier)
+{
+    writeRegister(RXM1SIDH, (byte)(identifier>>3));
+    writeRegister(RXM1SIDL, (byte)(identifier<<5));
+}