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Kevin |
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#include "msg_queues.h"
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#include "maindefs.h"
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//#include <i2c.h>
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#include "i2c.h"
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#pragma udata i2c_data
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unsigned char i2c_buffer[MAXI2CBUF];
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#pragma udata
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I2C_DATA *i2c_pdata;
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// Set up the data structures for the i2c code
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// Should be called once before any i2c routines are called
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void i2c_init(I2C_DATA *data) {
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i2c_pdata = data;
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i2c_pdata->buffer = i2c_buffer;
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i2c_pdata->buflen = 0;
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i2c_pdata->slave_event_count = 0;
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i2c_pdata->status = I2C_IDLE;
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i2c_pdata->slave_error_count = 0;
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i2c_pdata->bufind = 0;
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i2c_pdata->buflen = 0;
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i2c_pdata->slave_in_last_byte = 0;
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i2c_pdata->slave_sending_data = 0;
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i2c_pdata->slave_sending_blank_data = 0;
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i2c_pdata->mode = 0;
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i2c_pdata->master_dest_addr = 0;
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i2c_pdata->master_state = I2C_MASTER_IDLE;
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}
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// Setup the PIC to operate as a master.
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void i2c_configure_master() {
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i2c_pdata->mode = I2C_MODE_MASTER;
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TRISCbits.TRISC3 = 1;
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TRISCbits.TRISC4 = 1;
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SSPSTAT = 0x0;
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SSPCON1 = 0x0;
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SSPCON2 = 0x0;
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SSPCON1bits.SSPM = 0x8; // I2C Master Mode
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SSPADD = 0x63; // Operate at 100KHz (40MHz)
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SSPSTATbits.SMP = 1; // Disable Slew Rate Control
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SSPCON1bits.SSPEN = 1; // Enable MSSP Module
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}
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// Sends length number of bytes in msg to specified address (no R/W bit)
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void i2c_master_send(unsigned char address, unsigned char length, unsigned char *msg) {
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int i;
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if (length == 0)
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return;
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// Copy message to send into buffer and save length/address
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for (i = 0; i < length; i++) {
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i2c_pdata->buffer[i] = msg[i];
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}
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i2c_pdata->buflen = length;
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i2c_pdata->master_dest_addr = address;
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i2c_pdata->bufind = 0;
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// Change status to 'next' operation
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i2c_pdata->status = I2C_SEND_ADDR;
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i2c_pdata->master_state = I2C_MASTER_SEND;
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// Generate start condition
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SSPCON2bits.SEN = 1;
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}
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// Reads length number of bytes from address (no R/W bit)
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void i2c_master_recv(unsigned char address, unsigned char length) {
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if (length == 0)
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return;
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// Save length and address to get data from
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i2c_pdata->buflen = length;
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i2c_pdata->master_dest_addr = address;
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i2c_pdata->bufind = 0;
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// Change status to 'next' operation
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i2c_pdata->status = I2C_SEND_ADDR;
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i2c_pdata->master_state = I2C_MASTER_RECV;
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// Generate start condition
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SSPCON2bits.SEN = 1;
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}
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// Setup the PIC to operate as a slave. The address must not include the R/W bit
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void i2c_configure_slave(unsigned char addr) {
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i2c_pdata->mode = I2C_MODE_SLAVE;
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// Ensure the two lines are set for input (we are a slave)
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TRISCbits.TRISC3 = 1;
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TRISCbits.TRISC4 = 1;
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SSPADD = addr << 1; // Set the slave address
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SSPSTAT = 0x0;
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SSPCON1 = 0x0;
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SSPCON2 = 0x0;
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SSPCON1bits.SSPM = 0xE; // Enable Slave 7-bit w/ start/stop interrupts
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SSPSTATbits.SMP = 1; // Slew Off
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SSPCON2bits.SEN = 1; // Enable clock-stretching
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SSPCON1bits.SSPEN = 1; // Enable MSSP Module
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}
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void i2c_interrupt_handler() {
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// Call interrupt depending on which mode we are operating in
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if (i2c_pdata->mode == I2C_MODE_MASTER) {
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i2c_interrupt_master();
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} else if (i2c_pdata->mode == I2C_MODE_SLAVE) {
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i2c_interrupt_slave();
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}
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}
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// An internal subroutine used in the master version of the i2c_interrupt_handler
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void i2c_interrupt_master() {
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// If we are in the middle of sending data
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if (i2c_pdata->master_state == I2C_MASTER_SEND) {
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switch (i2c_pdata->status) {
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case I2C_IDLE:
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break;
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case I2C_SEND_ADDR:
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// Send the address with read bit set
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i2c_pdata->status = I2C_CHECK_ACK;
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SSPBUF = (i2c_pdata->master_dest_addr << 1) | 0x0;
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break;
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case I2C_CHECK_ACK:
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// Check if ACK is received or not
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if (!SSPCON2bits.ACKSTAT) {
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// If an ACK is received, send next byte of data
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if (i2c_pdata->bufind < i2c_pdata->buflen) {
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SSPBUF = i2c_pdata->buffer[i2c_pdata->bufind];
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i2c_pdata->bufind++;
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} else {
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// If no more data is to be sent, send stop bit
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i2c_pdata->status = I2C_IDLE;
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SSPCON2bits.PEN = 1;
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i2c_pdata->master_state = I2C_MASTER_IDLE;
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MQ_sendmsg_ToMainFromHigh(0, MSGTYPE_I2C_MASTER_SEND_COMPLETE, (void *) 0);
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}
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} else {
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// If a NACK is received, stop transmission and send error
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i2c_pdata->status = I2C_IDLE;
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SSPCON2bits.PEN = 1;
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i2c_pdata->master_state = I2C_MASTER_IDLE;
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MQ_sendmsg_ToMainFromHigh(0, MSGTYPE_I2C_MASTER_SEND_FAILED, (void *) 0);
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}
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break;
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}
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// If we are in the middle of receiving data
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} else if (i2c_pdata->master_state == I2C_MASTER_RECV) {
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switch (i2c_pdata->status) {
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case I2C_IDLE:
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break;
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case I2C_SEND_ADDR:
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// Send address with write bit set
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i2c_pdata->status = I2C_CHECK_ACK;
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SSPBUF = (i2c_pdata->master_dest_addr << 1) | 0x1;
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break;
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case I2C_CHECK_ACK:
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// Check if ACK is received
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if (!SSPCON2bits.ACKSTAT) {
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// If an ACK is received, set module to receive 1 byte of data
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i2c_pdata->status = I2C_RCV_DATA;
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SSPCON2bits.RCEN = 1;
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} else {
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// If a NACK is received, stop transmission and send error
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i2c_pdata->status = I2C_IDLE;
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SSPCON2bits.PEN = 1;
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i2c_pdata->master_state = I2C_MASTER_IDLE;
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MQ_sendmsg_ToMainFromHigh(0, MSGTYPE_I2C_MASTER_RECV_FAILED, (void *) 0);
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}
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break;
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case I2C_RCV_DATA:
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// On receive, save byte into buffer
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i2c_pdata->buffer[i2c_pdata->bufind] = SSPBUF;
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i2c_pdata->bufind++;
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if (i2c_pdata->bufind < i2c_pdata->buflen) {
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// If we still need to read, send an ACK to the slave
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i2c_pdata->status = I2C_REQ_DATA;
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SSPCON2bits.ACKDT = 0; // ACK
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SSPCON2bits.ACKEN = 1;
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} else {
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// If we are done reading, send an NACK to the slave
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i2c_pdata->status = I2C_SEND_STOP;
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SSPCON2bits.ACKDT = 1; // NACK
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SSPCON2bits.ACKEN = 1;
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}
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break;
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case I2C_REQ_DATA:
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// Set module to receive one byte of data
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i2c_pdata->status = I2C_RCV_DATA;
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SSPCON2bits.RCEN = 1;
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break;
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case I2C_SEND_STOP:
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// Send the stop bit and copy message to send to Main()
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i2c_pdata->status = I2C_IDLE;
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SSPCON2bits.PEN = 1;
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i2c_pdata->master_state = I2C_MASTER_IDLE;
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MQ_sendmsg_ToMainFromHigh(i2c_pdata->buflen, MSGTYPE_I2C_MASTER_RECV_COMPLETE, (void *) i2c_pdata->buffer);
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break;
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}
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}
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}
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// An internal subroutine used in the slave version of the i2c_interrupt_handler
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void i2c_handle_start(unsigned char data_read) {
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i2c_pdata->slave_event_count = 1;
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i2c_pdata->buflen = 0;
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// Check to see if we also got the address
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if (data_read) {
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if (SSPSTATbits.D_A == 1) {
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DBG_PRINT_I2C("I2C Start: (ERROR) no address recieved\r\n");
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// This is bad because we got data and we wanted an address
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i2c_pdata->status = I2C_IDLE;
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i2c_pdata->slave_error_count++;
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i2c_pdata->slave_error_code = I2C_ERR_NOADDR;
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} else {
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if (SSPSTATbits.R_W == 1) {
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i2c_pdata->status = I2C_SEND_DATA;
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} else {
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i2c_pdata->status = I2C_RCV_DATA;
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}
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}
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} else {
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i2c_pdata->status = I2C_STARTED;
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}
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}
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void i2c_interrupt_slave() {
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unsigned char i2c_data;
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unsigned char data_read_from_buffer = 0;
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unsigned char data_written_to_buffer = 0;
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unsigned char msg_send_data_to_main = 0;
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unsigned char overrun_error = 0;
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unsigned char error_buf[3];
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unsigned char msgtype = 0;
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// Clear SSPOV (overflow bit)
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if (SSPCON1bits.SSPOV == 1) {
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DBG_PRINT_I2C("I2C: overflow detected\r\n");
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SSPCON1bits.SSPOV = 0;
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// We failed to read the buffer in time, so we know we
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// can't properly receive this message, just put us in the
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// a state where we are looking for a new message
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i2c_pdata->status = I2C_IDLE;
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overrun_error = 1;
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i2c_pdata->slave_error_count++;
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i2c_pdata->slave_error_code = I2C_ERR_OVERRUN;
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}
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// Read SPPxBUF if it is full
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if (SSPSTATbits.BF == 1) {
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i2c_data = SSPBUF;
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DBG_PRINT_I2C("I2C: data read from buffer: %x\r\n", SSPBUF);
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data_read_from_buffer = 1;
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}
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if (!overrun_error) {
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switch (i2c_pdata->status) {
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case I2C_IDLE:
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{
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// Ignore anything except a start
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if (SSPSTATbits.S == 1) {
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i2c_handle_start(data_read_from_buffer);
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// If we see a slave read, then we need to handle it here
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if (i2c_pdata->status == I2C_SEND_DATA) {
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// Return the first byte (message id)
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SSPBUF = 0x3;
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}
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}
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break;
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}
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case I2C_STARTED:
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{
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// In this case, we expect either an address or a stop bit
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if (SSPSTATbits.P == 1) {
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// We need to check to see if we also read an address (a message of length 0)
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i2c_pdata->slave_event_count++;
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280 |
if (data_read_from_buffer) {
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281 |
if (SSPSTATbits.D_A == 0) {
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msg_send_data_to_main = 1;
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283 |
} else {
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284 |
DBG_PRINT_I2C("I2C: (ERROR) no data recieved\r\n");
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i2c_pdata->slave_error_count++;
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i2c_pdata->slave_error_code = I2C_ERR_NODATA;
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}
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}
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// Return to idle mode
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290 |
i2c_pdata->status = I2C_IDLE;
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291 |
} else if (data_read_from_buffer) {
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292 |
i2c_pdata->slave_event_count++;
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293 |
if (SSPSTATbits.D_A == 0) {
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if (SSPSTATbits.R_W == 0) { // Slave write
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i2c_pdata->status = I2C_RCV_DATA;
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} else { // Slave read
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i2c_pdata->status = I2C_SEND_DATA;
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// Return the first byte (message id)
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SSPBUF = 0x3;
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}
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301 |
} else {
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DBG_PRINT_I2C("I2C: (ERROR) no data recieved\r\n");
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i2c_pdata->slave_error_count++;
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i2c_pdata->status = I2C_IDLE;
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305 |
i2c_pdata->slave_error_code = I2C_ERR_NODATA;
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}
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}
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break;
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}
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310 |
case I2C_SEND_DATA:
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311 |
{
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312 |
// If we arnt current in the middle of sending data, check to see
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313 |
// if there is a message in the queue to send
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314 |
if (!i2c_pdata->slave_sending_data) {
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315 |
// Check the message type of the next message in queue
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316 |
msgtype = MQ_peek_FromMainToHigh();
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317 |
if (msgtype != MSGTYPE_I2C_REPLY || msgtype == 0) {
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318 |
// If the message queue is empty or to another interrupt processor, return 0xFF
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319 |
DBG_PRINT_I2C("I2C: Returning 0xFF [%d:%d]\r\n", 0, i2c_pdata->slave_in_last_byte-1);
|
|
|
320 |
SSPBUF = 0xFF;
|
|
|
321 |
i2c_pdata->bufind = 1;
|
|
|
322 |
i2c_pdata->slave_sending_data = 1;
|
|
|
323 |
i2c_pdata->slave_sending_blank_data = 1;
|
|
|
324 |
data_written_to_buffer = 1;
|
|
|
325 |
} else {
|
|
|
326 |
i2c_pdata->buflen = MQ_recvmsg_FromMainToHigh(MSGLEN, (unsigned char *)i2c_pdata->slave_outbufmsgtype, (void *) i2c_pdata->buffer);
|
|
|
327 |
// DBG_PRINT_I2C("%x\r\n",i2c_ptr->buffer[0]);
|
|
|
328 |
// DBG_PRINT_I2C("I2C: buffer Message Length: %d\r\n",i2c_ptr->outbuflen);
|
|
|
329 |
if (i2c_pdata->buflen > 0) {
|
|
|
330 |
// Otherwise return the first byte of data
|
|
|
331 |
DBG_PRINT_I2C("I2C: Returning %x [%d,%d]\r\n", i2c_pdata->buffer[0], 0, i2c_pdata->buflen-1);
|
|
|
332 |
SSPBUF = i2c_pdata->buffer[0];
|
|
|
333 |
i2c_pdata->bufind = 1;
|
|
|
334 |
i2c_pdata->slave_sending_data = 1;
|
|
|
335 |
data_written_to_buffer = 1;
|
|
|
336 |
} else {
|
|
|
337 |
DBG_PRINT_I2C("I2C: (ERROR) Unexpected msg in queue, type = %x\r\n", i2c_pdata->slave_outbufmsgtype);
|
|
|
338 |
}
|
|
|
339 |
}
|
|
|
340 |
} else if (i2c_pdata->slave_sending_blank_data) {
|
|
|
341 |
// If we are currently sending 0xFFs back, keep sending for the requested number of bytes
|
|
|
342 |
if (i2c_pdata->bufind < i2c_pdata->slave_in_last_byte) {
|
|
|
343 |
DBG_PRINT_I2C("I2C: Returning 0xFF [%d:%d]\r\n", i2c_pdata->bufind, i2c_pdata->slave_in_last_byte-1);
|
|
|
344 |
SSPBUF = 0xFF;
|
|
|
345 |
i2c_pdata->bufind++;
|
|
|
346 |
data_written_to_buffer = 1;
|
|
|
347 |
} else {
|
|
|
348 |
// We have nothing left to send
|
|
|
349 |
i2c_pdata->slave_sending_data = 0;
|
|
|
350 |
i2c_pdata->slave_sending_blank_data = 0;
|
|
|
351 |
i2c_pdata->status = I2C_IDLE;
|
|
|
352 |
}
|
|
|
353 |
} else {
|
|
|
354 |
// Otherwise keep sending back the requested data
|
|
|
355 |
if (i2c_pdata->bufind < i2c_pdata->buflen) {
|
|
|
356 |
DBG_PRINT_I2C("I2C: Returning %x [%d,%d]\r\n", i2c_pdata->buffer[i2c_pdata->bufind], i2c_pdata->bufind, i2c_pdata->buflen-1);
|
|
|
357 |
SSPBUF = i2c_pdata->buffer[i2c_pdata->bufind];
|
|
|
358 |
i2c_pdata->bufind++;
|
|
|
359 |
data_written_to_buffer = 1;
|
|
|
360 |
} else {
|
|
|
361 |
// We have nothing left to send
|
|
|
362 |
i2c_pdata->slave_sending_data = 0;
|
|
|
363 |
i2c_pdata->status = I2C_IDLE;
|
|
|
364 |
}
|
|
|
365 |
}
|
|
|
366 |
break;
|
|
|
367 |
}
|
|
|
368 |
case I2C_RCV_DATA:
|
|
|
369 |
{
|
|
|
370 |
// We expect either data or a stop bit or a (if a restart, an addr)
|
|
|
371 |
if (SSPSTATbits.P == 1) {
|
|
|
372 |
// We need to check to see if we also read data
|
|
|
373 |
i2c_pdata->slave_event_count++;
|
|
|
374 |
if (data_read_from_buffer) {
|
|
|
375 |
if (SSPSTATbits.D_A == 1) {
|
|
|
376 |
i2c_pdata->buffer[i2c_pdata->buflen] = i2c_data;
|
|
|
377 |
i2c_pdata->buflen++;
|
|
|
378 |
msg_send_data_to_main = 1;
|
|
|
379 |
} else {
|
|
|
380 |
DBG_PRINT_I2C("I2C: (ERROR) no data recieved\r\n");
|
|
|
381 |
i2c_pdata->slave_error_count++;
|
|
|
382 |
i2c_pdata->slave_error_code = I2C_ERR_NODATA;
|
|
|
383 |
i2c_pdata->status = I2C_IDLE;
|
|
|
384 |
}
|
|
|
385 |
} else {
|
|
|
386 |
msg_send_data_to_main = 1;
|
|
|
387 |
}
|
|
|
388 |
i2c_pdata->status = I2C_IDLE;
|
|
|
389 |
} else if (data_read_from_buffer) {
|
|
|
390 |
i2c_pdata->slave_event_count++;
|
|
|
391 |
if (SSPSTATbits.D_A == 1) {
|
|
|
392 |
i2c_pdata->buffer[i2c_pdata->buflen] = i2c_data;
|
|
|
393 |
i2c_pdata->buflen++;
|
|
|
394 |
} else /* a restart */ {
|
|
|
395 |
if (SSPSTATbits.R_W == 1) {
|
|
|
396 |
i2c_pdata->status = I2C_SEND_DATA;
|
|
|
397 |
msg_send_data_to_main = 1;
|
|
|
398 |
// Return the first byte (message id)
|
|
|
399 |
SSPBUF = 0x3;
|
|
|
400 |
|
|
|
401 |
} else { // Bad to recv an address again, we aren't ready
|
|
|
402 |
DBG_PRINT_I2C("I2C: (ERROR) no data recieved\r\n");
|
|
|
403 |
i2c_pdata->slave_error_count++;
|
|
|
404 |
i2c_pdata->slave_error_code = I2C_ERR_NODATA;
|
|
|
405 |
i2c_pdata->status = I2C_IDLE;
|
|
|
406 |
}
|
|
|
407 |
}
|
|
|
408 |
}
|
|
|
409 |
break;
|
|
|
410 |
}
|
|
|
411 |
}
|
|
|
412 |
}
|
|
|
413 |
|
|
|
414 |
// Release the clock stretching bit (if we should)
|
|
|
415 |
if (data_read_from_buffer || data_written_to_buffer) {
|
|
|
416 |
// Release the clock
|
|
|
417 |
if (SSPCON1bits.CKP == 0) {
|
|
|
418 |
SSPCON1bits.CKP = 1;
|
|
|
419 |
}
|
|
|
420 |
}
|
|
|
421 |
|
|
|
422 |
// Must check if the message is too long
|
|
|
423 |
if ((i2c_pdata->buflen > MAXI2CBUF - 2) && (!msg_send_data_to_main)) {
|
|
|
424 |
DBG_PRINT_I2C("I2C: (ERROR) message too long\r\n");
|
|
|
425 |
i2c_pdata->status = I2C_IDLE;
|
|
|
426 |
i2c_pdata->slave_error_count++;
|
|
|
427 |
i2c_pdata->slave_error_code = I2C_ERR_MSGTOOLONG;
|
|
|
428 |
}
|
|
|
429 |
|
|
|
430 |
if (msg_send_data_to_main) {
|
|
|
431 |
DBG_PRINT_I2C("I2C: sending message to main()\r\n");
|
|
|
432 |
i2c_pdata->slave_in_last_byte = i2c_pdata->buffer[i2c_pdata->buflen-1];
|
|
|
433 |
i2c_pdata->buffer[i2c_pdata->buflen] = i2c_pdata->slave_event_count;
|
|
|
434 |
MQ_sendmsg_ToMainFromHigh(i2c_pdata->buflen + 1, MSGTYPE_I2C_DATA, (void *) i2c_pdata->buffer);
|
|
|
435 |
i2c_pdata->buflen = 0;
|
|
|
436 |
} else if (i2c_pdata->slave_error_count >= I2C_ERR_THRESHOLD) {
|
|
|
437 |
DBG_PRINT_I2C("I2C: (ERROR) error threshold passed\r\n");
|
|
|
438 |
error_buf[0] = i2c_pdata->slave_error_count;
|
|
|
439 |
error_buf[1] = i2c_pdata->slave_error_code;
|
|
|
440 |
error_buf[2] = i2c_pdata->slave_event_count;
|
|
|
441 |
MQ_sendmsg_ToMainFromHigh(sizeof (unsigned char) *3, MSGTYPE_I2C_DBG, (void *) error_buf);
|
|
|
442 |
i2c_pdata->slave_error_count = 0;
|
|
|
443 |
}
|
|
|
444 |
}
|
|
|
445 |
|
|
|
446 |
unsigned char i2c_master_busy() {
|
|
|
447 |
if (i2c_pdata->master_state == I2C_MASTER_IDLE) {
|
|
|
448 |
return 0;
|
|
|
449 |
} else {
|
|
|
450 |
return 1;
|
|
|
451 |
}
|
|
|
452 |
}
|