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Kevin |
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#include "defines.h"
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#include "I2C1.h"
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extern I2C1_DATA i2c_data;
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// Set up the data structures for the base_I2C.code
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// Should be called once before any i2c routines are called
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void I2C1_Init(void) {
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i2c_data.buffer_in_len = 0;
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i2c_data.buffer_in_read_ind = 0;
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i2c_data.buffer_in_write_ind = 0;
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i2c_data.operating_state = I2C_IDLE;
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i2c_data.return_status = 0;
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i2c_data.master_dest_addr = 0;
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i2c_data.master_status = I2C_MASTER_IDLE;
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// Enable I2C interrupt
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PIE1bits.SSP1IE = 1;
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}
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// Setup the PIC to operate as a master.
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void I2C1_Configure_Master(uint8_t speed) {
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// i2c_data.operating_mode = I2C_MODE_MASTER;
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I2C_1_CLK_TRIS = 1;
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I2C_1_DAT_TRIS = 1;
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SSP1STAT = 0x0;
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SSP1CON1 = 0x0;
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SSP1CON2 = 0x0;
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SSP1CON3 = 0x0;
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SSP1CON1bits.SSPM = 0x8; // I2C Master Mode
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if (speed == 0x01) {
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SSP1ADD = 0x13; // Operate at 400KHz (32MHz)
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SSP1STATbits.SMP = 1; // Disable Slew Rate Control
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} else if (speed == 0x02) {
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SSP1ADD = 0x07; // Operate at 1Mhz (32Mhz)
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SSP1STATbits.SMP = 1; // Disable Slew Rate Control
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} else {
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SSP1ADD = 0x4F; // Operate at 100KHz (32MHz)
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SSP1STATbits.SMP = 0; // Enable Slew Rate Control
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}
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SSP1CON1bits.SSPEN = 1; // Enable MSSP1 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 I2C1_Master_Send(uint8_t address, uint8_t length, uint8_t *msg) {
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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 (uint8_t i = 0; i < length; i++) {
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i2c_data.buffer_in[i] = msg[i];
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}
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i2c_data.buffer_in_len = length;
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i2c_data.master_dest_addr = address;
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i2c_data.buffer_in_read_ind = 0;
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i2c_data.buffer_in_write_ind = 0;
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// Change status to 'next' operation
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i2c_data.operating_state = I2C_SEND_ADDR;
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i2c_data.master_status = I2C_MASTER_SEND;
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// Generate start condition
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SSP1CON2bits.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 I2C1_Master_Recv(uint8_t address, uint8_t 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_data.buffer_in_len = length;
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i2c_data.master_dest_addr = address;
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i2c_data.buffer_in_read_ind = 0;
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i2c_data.buffer_in_write_ind = 0;
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// Change status to 'next' operation
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i2c_data.operating_state = I2C_SEND_ADDR;
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i2c_data.master_status = I2C_MASTER_RECV;
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// Generate start condition
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SSP1CON2bits.SEN = 1;
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}
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// Writes msg to address then reads length number of bytes from address
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void I2C1_Master_Restart(uint8_t address, uint8_t msg, uint8_t length) {
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uint8_t c;
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if (length == 0) {
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c = msg;
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I2C1_Master_Send(address, 1, &c);
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return;
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}
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// Save length and address to get data from
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i2c_data.buffer_in[0] = msg;
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i2c_data.buffer_in_len = length;
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i2c_data.master_dest_addr = address;
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i2c_data.buffer_in_read_ind = 0;
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i2c_data.buffer_in_write_ind = 0;
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// Change status to 'next' operation
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i2c_data.operating_state = I2C_SEND_ADDR;
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i2c_data.master_status = I2C_MASTER_RESTART;
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// Generate start condition
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SSP1CON2bits.SEN = 1;
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}
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void I2C1_Interrupt_Handler() {
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// If we are in the middle of sending data
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if (i2c_data.master_status == I2C_MASTER_SEND) {
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switch (i2c_data.operating_state) {
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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_data.operating_state = I2C_CHECK_ACK_SEND;
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SSP1BUF = (i2c_data.master_dest_addr << 1) | 0x0;
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break;
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case I2C_CHECK_ACK_SEND:
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// Check if ACK is received or not
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if (!SSP1CON2bits.ACKSTAT) {
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// If an ACK is received, send next byte of data
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if (i2c_data.buffer_in_read_ind < i2c_data.buffer_in_len) {
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SSP1BUF = i2c_data.buffer_in[i2c_data.buffer_in_read_ind];
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i2c_data.buffer_in_read_ind++;
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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_data.operating_state = I2C_IDLE;
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SSP1CON2bits.PEN = 1;
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i2c_data.master_status = I2C_MASTER_IDLE;
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i2c_data.return_status = I2C_SEND_OK;
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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_data.operating_state = I2C_IDLE;
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SSP1CON2bits.PEN = 1;
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i2c_data.master_status = I2C_MASTER_IDLE;
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i2c_data.return_status = I2C_SEND_FAIL;
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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_data.master_status == I2C_MASTER_RECV) {
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switch (i2c_data.operating_state) {
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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_data.operating_state = I2C_CHECK_ACK_RECV;
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uint8_t tmp = (i2c_data.master_dest_addr << 1);
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tmp |= 0x01;
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SSP1BUF = tmp;
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break;
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case I2C_CHECK_ACK_RECV:
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// Check if ACK is received
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if (!SSP1CON2bits.ACKSTAT) {
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// If an ACK is received, set module to receive 1 byte of data
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i2c_data.operating_state = I2C_RCV_DATA;
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SSP1CON2bits.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_data.operating_state = I2C_IDLE;
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SSP1CON2bits.PEN = 1;
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i2c_data.master_status = I2C_MASTER_IDLE;
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i2c_data.return_status = I2C_RECV_FAIL;
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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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// TODO: Handle I2C buffer overflow
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i2c_data.buffer_in[i2c_data.buffer_in_write_ind] = SSP1BUF;
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i2c_data.buffer_in_write_ind++;
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if (i2c_data.buffer_in_write_ind < i2c_data.buffer_in_len) {
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// If we still need to read, send an ACK to the slave
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i2c_data.operating_state = I2C_REQ_DATA;
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SSP1CON2bits.ACKDT = 0; // ACK
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SSP1CON2bits.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_data.operating_state = I2C_SEND_STOP;
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SSP1CON2bits.ACKDT = 1; // NACK
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SSP1CON2bits.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_data.operating_state = I2C_RCV_DATA;
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SSP1CON2bits.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_data.operating_state = I2C_IDLE;
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SSP1CON2bits.PEN = 1;
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i2c_data.master_status = I2C_MASTER_IDLE;
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i2c_data.return_status = I2C_RECV_OK;
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break;
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}
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} else if (i2c_data.master_status == I2C_MASTER_RESTART) {
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switch (i2c_data.operating_state) {
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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_data.operating_state = I2C_CHECK_ACK_SEND;
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SSP1BUF = (i2c_data.master_dest_addr << 1) | 0x0;
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break;
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case I2C_CHECK_ACK_SEND:
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// Check if ACK is received or not
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if (!SSP1CON2bits.ACKSTAT) {
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// If an ACK is received, send first byte of data
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SSP1BUF = i2c_data.buffer_in[0];
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i2c_data.operating_state = I2C_CHECK_ACK_RESTART;
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} else {
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// If a NACK is received, stop transmission and send error
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i2c_data.operating_state = I2C_IDLE;
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SSP1CON2bits.PEN = 1;
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i2c_data.master_status = I2C_MASTER_IDLE;
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i2c_data.return_status = I2C_SEND_FAIL;
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}
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break;
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case I2C_CHECK_ACK_RESTART:
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if (!SSP1CON2bits.ACKSTAT) {
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SSP1CON2bits.RSEN = 1;
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i2c_data.operating_state = I2C_SEND_ADDR_2;
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} else {
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// If a NACK is received, stop transmission and send error
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i2c_data.operating_state = I2C_IDLE;
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SSP1CON2bits.PEN = 1;
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i2c_data.master_status = I2C_MASTER_IDLE;
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i2c_data.return_status = I2C_SEND_FAIL;
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}
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break;
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case I2C_SEND_ADDR_2:
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// Send the address with read bit set
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i2c_data.operating_state = I2C_CHECK_ACK_RECV;
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uint8_t tmp = (i2c_data.master_dest_addr << 1);
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tmp |= 0x01;
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SSP1BUF = tmp;
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break;
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case I2C_CHECK_ACK_RECV:
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// Check if ACK is received
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if (!SSP1CON2bits.ACKSTAT) {
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// If an ACK is received, set module to receive 1 byte of data
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i2c_data.operating_state = I2C_RCV_DATA;
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SSP1CON2bits.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_data.operating_state = I2C_IDLE;
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SSP1CON2bits.PEN = 1;
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i2c_data.master_status = I2C_MASTER_IDLE;
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i2c_data.return_status = I2C_RECV_FAIL;
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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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// TODO: Handle I2C buffer overflow
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i2c_data.buffer_in[i2c_data.buffer_in_write_ind] = SSP1BUF;
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i2c_data.buffer_in_write_ind++;
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if (i2c_data.buffer_in_write_ind < i2c_data.buffer_in_len) {
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// If we still need to read, send an ACK to the slave
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i2c_data.operating_state = I2C_REQ_DATA;
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SSP1CON2bits.ACKDT = 0; // ACK
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SSP1CON2bits.ACKEN = 1;
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269 |
} else {
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// If we are done reading, send an NACK to the slave
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i2c_data.operating_state = I2C_SEND_STOP;
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SSP1CON2bits.ACKDT = 1; // NACK
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SSP1CON2bits.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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278 |
i2c_data.operating_state = I2C_RCV_DATA;
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SSP1CON2bits.RCEN = 1;
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280 |
break;
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281 |
case I2C_SEND_STOP:
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// Send the stop bit
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283 |
i2c_data.operating_state = I2C_IDLE;
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284 |
SSP1CON2bits.PEN = 1;
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285 |
i2c_data.master_status = I2C_MASTER_IDLE;
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i2c_data.return_status = I2C_RECV_OK;
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287 |
break;
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288 |
}
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}
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}
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292 |
/* Returns 0 if I2C module is currently busy, otherwise returns status code */
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293 |
uint8_t I2C1_Get_Status() {
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294 |
// if (i2c_data.operating_mode == I2C_MODE_MASTER) {
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295 |
if (i2c_data.master_status != I2C_MASTER_IDLE || i2c_data.buffer_in_len == 0) {
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296 |
return 0;
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297 |
} else {
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298 |
return i2c_data.return_status;
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299 |
}
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300 |
}
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301 |
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302 |
uint8_t I2C1_Buffer_Len() {
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303 |
return i2c_data.buffer_in_len;
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304 |
}
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305 |
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306 |
/* Returns 0 if I2C module is currently busy, otherwise returns buffer length */
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307 |
uint8_t I2C1_Read_Buffer(uint8_t *buffer) {
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308 |
uint8_t i = 0;
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309 |
while (i2c_data.buffer_in_len != 0) {
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310 |
buffer[i] = i2c_data.buffer_in[i2c_data.buffer_in_read_ind];
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311 |
i++;
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312 |
if (i2c_data.buffer_in_read_ind == MAXI2C1BUF-1) {
|
|
|
313 |
i2c_data.buffer_in_read_ind = 0;
|
|
|
314 |
} else {
|
|
|
315 |
i2c_data.buffer_in_read_ind++;
|
|
|
316 |
}
|
|
|
317 |
i2c_data.buffer_in_len--;
|
|
|
318 |
}
|
|
|
319 |
return i;
|
|
|
320 |
}
|