| 0,0 → 1,472 |
|---|
| #include "defines.h" |
| #include "I2C1.h" |
| |
| static I2C1_DATA *i2c_data_p; |
| |
| // Initialize the data structures, should be called once before any I2C routines are called |
| void I2C1_Init(I2C1_DATA *data, uint8_t speed, uint8_t address) { |
| i2c_data_p = data; |
| |
| i2c_data_p->buffer_in_len = 0; |
| i2c_data_p->buffer_in_read_ind = 0; |
| i2c_data_p->buffer_in_write_ind = 0; |
| |
| i2c_data_p->buffer_out_ind = 0; |
| i2c_data_p->buffer_out_len = 0; |
| |
| i2c_data_p->operating_state = I2C1_IDLE; |
| i2c_data_p->return_status = 0; |
| |
| i2c_data_p->slave_in_last_byte = 0; |
| i2c_data_p->slave_sending_data = 0; |
| |
| i2c_data_p->master_dest_addr = 0; |
| i2c_data_p->master_status = I2C1_MASTER_IDLE; |
| |
| INTDisableInterrupts(); |
| |
| // Enable the I2C module and set the clock stretch enable bit |
| // Note: Automatically overrides any other pin settings |
| I2C1CONSET = 0x00008040; |
| I2C1ADD = address; |
| if (speed == 0x01) { |
| I2C1BRG = 0x0BE; // Operate at 200kHZ (80MHz) |
| I2C1CONbits.DISSLW = 0; // Slew rate control enabled |
| } else if (speed == 0x02) { |
| I2C1BRG = 0x05A; // Operate at 400kHZ (80MHz) |
| I2C1CONbits.DISSLW = 1; // Slew rate control disabled |
| } else if (speed == 0x03) { |
| I2C1BRG = 0x020; // Operate at 1MHz (80MHz) |
| I2C1CONbits.DISSLW = 1; // Slew rate control disabled |
| } else { |
| I2C1BRG = 0x186; // Operate at 100kHZ (80MHz) |
| I2C1CONbits.DISSLW = 0; // Slew rate control enabled |
| } |
| IFS0CLR = 0xE0000000; // Clear any existing events |
| IPC6CLR = 0x00001F00; // Reset priority levels |
| IPC6SET = 0x00001600; // Set IPL=6, Subpriority 2 |
| IEC0SET = 0xE0000000; // Enable I2C1 interrupts |
| |
| INTEnableInterrupts(); |
| } |
| |
| // Sends length number of bytes in msg to specified address (no R/W bit) |
| // Will return status I2C1_SEND_OK or I2C1_SEND_FAIL |
| void I2C1_Master_Send(uint8_t address, uint8_t *msg, uint32_t length) { |
| uint32_t i; |
| if (length == 0) |
| return; |
| |
| // Copy message to send into buffer and save length/address |
| for (i = 0; i < length; i++) { |
| i2c_data_p->buffer_in[i] = msg[i]; |
| } |
| i2c_data_p->buffer_in_len = length; |
| i2c_data_p->master_dest_addr = address; |
| i2c_data_p->buffer_in_read_ind = 0; |
| i2c_data_p->buffer_in_write_ind = 0; |
| |
| // Change status to 'next' operation |
| i2c_data_p->operating_state = I2C1_SEND_ADDR; |
| i2c_data_p->master_status = I2C1_MASTER_SEND; |
| |
| // Generate start condition |
| I2C1CONbits.SEN = 1; |
| } |
| |
| // Reads length number of bytes from address (no R/W bit) |
| // Will return status I2C1_RECV_OK or I2C1_RECV_FAIL |
| void I2C1_Master_Recv(uint8_t address, uint32_t length) { |
| if (length == 0) |
| return; |
| |
| // Save length and address to get data from |
| i2c_data_p->buffer_in_len = length; |
| i2c_data_p->master_dest_addr = address; |
| i2c_data_p->buffer_in_read_ind = 0; |
| i2c_data_p->buffer_in_write_ind = 0; |
| |
| // Change status to 'next' operation |
| i2c_data_p->operating_state = I2C1_SEND_ADDR; |
| i2c_data_p->master_status = I2C1_MASTER_RECV; |
| |
| // Generate start condition |
| I2C1CONbits.SEN = 1; |
| } |
| |
| // Writes msg to address then reads length number of bytes from address |
| // Will return status I2C1_SEND_FAIL or I2C1_RECV_FAIL or I2C1_RECV_OK |
| void I2C1_Master_Restart(uint8_t address, uint8_t msg, uint32_t length) { |
| uint8_t c; |
| if (length == 0) { |
| c = msg; |
| I2C1_Master_Send(address, &c, 1); |
| return; |
| } |
| |
| // Save length and address to get data from |
| i2c_data_p->buffer_in[0] = msg; |
| i2c_data_p->buffer_in_len = length; |
| i2c_data_p->master_dest_addr = address; |
| i2c_data_p->buffer_in_read_ind = 0; |
| i2c_data_p->buffer_in_write_ind = 0; |
| |
| // Change status to 'next' operation |
| i2c_data_p->operating_state = I2C1_SEND_ADDR; |
| i2c_data_p->master_status = I2C1_MASTER_RESTART; |
| |
| // Generate start condition |
| I2C1CONbits.SEN = 1; |
| } |
| |
| void __ISR(_I2C_1_VECTOR, ipl5) __I2C_1_Interrupt_Handler(void) { |
| // Bus collision event |
| if (IFS0bits.I2C1BIF) { |
| // TODO: Handle bus collision events here |
| IFS0CLR = 0x20000000; |
| } |
| // Slave event |
| if (IFS0bits.I2C1SIF) { |
| I2C1_Interrupt_Slave(); |
| IFS0CLR = 0x40000000; |
| } |
| // Master event |
| if (IFS0bits.I2C1MIF) { |
| I2C1_Interrupt_Master(); |
| IFS0CLR = 0x80000000; |
| } |
| } |
| |
| // An internal subroutine used in the master version of the i2c_interrupt_handler |
| void I2C1_Interrupt_Master() { |
| |
| /* The PIC32 family has different master interrupts than the PIC8 family |
| * Master mode operations that generate a slave interrupt are: |
| * 1. Start condition |
| * 2. Repeated start sequence |
| * 3. Stop condition |
| * 4. Data transfer byte received |
| * 5. During a send ACK or NACK sequence to slave |
| * 6. Data transfer byte transmitted |
| * 7. During a slave-detected stop |
| */ |
| |
| if (I2C1STATbits.IWCOL == 1) { |
| // TODO: Handle write collisions |
| I2C1STATbits.IWCOL = 0; |
| } |
| |
| // If we are in the middle of sending data |
| if (i2c_data_p->master_status == I2C1_MASTER_SEND) { |
| switch (i2c_data_p->operating_state) { |
| case I2C1_IDLE: |
| break; |
| case I2C1_SEND_ADDR: |
| // Send the address with read bit set |
| i2c_data_p->operating_state = I2C1_CHECK_ACK_SEND; |
| I2C1TRN = (i2c_data_p->master_dest_addr << 1) | 0x0; |
| break; |
| case I2C1_CHECK_ACK_SEND: |
| // Check if ACK is received or not |
| if (!I2C1STATbits.ACKSTAT) { |
| // If an ACK is received, send next byte of data |
| if (i2c_data_p->buffer_in_read_ind < i2c_data_p->buffer_in_len) { |
| I2C1TRN = i2c_data_p->buffer_in[i2c_data_p->buffer_in_read_ind]; |
| i2c_data_p->buffer_in_read_ind++; |
| } else { |
| // If no more data is to be sent, send stop bit |
| i2c_data_p->operating_state = I2C1_STOPPED; |
| I2C1CONbits.PEN = 1; |
| i2c_data_p->return_status = I2C1_SEND_OK; |
| } |
| } else { |
| // If a NACK is received, stop transmission and send error |
| i2c_data_p->operating_state = I2C1_STOPPED; |
| I2C1CONbits.PEN = 1; |
| i2c_data_p->return_status = I2C1_SEND_FAIL; |
| } |
| break; |
| case I2C1_STOPPED: |
| i2c_data_p->operating_state = I2C1_IDLE; |
| i2c_data_p->master_status = I2C1_MASTER_IDLE; |
| break; |
| } |
| // If we are in the middle of receiving data |
| } else if (i2c_data_p->master_status == I2C1_MASTER_RECV) { |
| switch (i2c_data_p->operating_state) { |
| case I2C1_IDLE: |
| break; |
| case I2C1_SEND_ADDR: |
| // Send address with write bit set |
| i2c_data_p->operating_state = I2C1_CHECK_ACK_RECV; |
| I2C1TRN = (i2c_data_p->master_dest_addr << 1) | 0x1; |
| break; |
| case I2C1_CHECK_ACK_RECV: |
| // Check if ACK is received |
| if (!I2C1STATbits.ACKSTAT) { |
| // If an ACK is received, set module to receive 1 byte of data |
| i2c_data_p->operating_state = I2C1_RCV_DATA; |
| I2C1CONbits.RCEN = 1; |
| } else { |
| // If a NACK is received, stop transmission and send error |
| i2c_data_p->operating_state = I2C1_STOPPED; |
| I2C1CONbits.PEN = 1; |
| i2c_data_p->return_status = I2C1_RECV_FAIL; |
| } |
| break; |
| case I2C1_RCV_DATA: |
| // On receive, save byte into buffer |
| // TODO: Handle possible I2C buffer overflow |
| i2c_data_p->buffer_in[i2c_data_p->buffer_in_write_ind] = I2C1RCV; |
| i2c_data_p->buffer_in_write_ind++; |
| if (i2c_data_p->buffer_in_write_ind < i2c_data_p->buffer_in_len) { |
| // If we still need to read, send an ACK to the slave |
| i2c_data_p->operating_state = I2C1_REQ_DATA; |
| I2C1CONbits.ACKDT = 0; // ACK |
| I2C1CONbits.ACKEN = 1; |
| } else { |
| // If we are done reading, send an NACK to the slave |
| i2c_data_p->operating_state = I2C1_SEND_STOP; |
| I2C1CONbits.ACKDT = 1; // NACK |
| I2C1CONbits.ACKEN = 1; |
| } |
| break; |
| case I2C1_REQ_DATA: |
| // Set module to receive one byte of data |
| i2c_data_p->operating_state = I2C1_RCV_DATA; |
| I2C1CONbits.RCEN = 1; |
| break; |
| case I2C1_SEND_STOP: |
| // Send the stop bit |
| i2c_data_p->operating_state = I2C1_STOPPED; |
| I2C1CONbits.PEN = 1; |
| i2c_data_p->return_status = I2C1_RECV_OK; |
| break; |
| case I2C1_STOPPED: |
| i2c_data_p->operating_state = I2C1_IDLE; |
| i2c_data_p->master_status = I2C1_MASTER_IDLE; |
| break; |
| } |
| } else if (i2c_data_p->master_status == I2C1_MASTER_RESTART) { |
| switch (i2c_data_p->operating_state) { |
| case I2C1_IDLE: |
| break; |
| case I2C1_SEND_ADDR: |
| // Send the address with read bit set |
| i2c_data_p->operating_state = I2C1_CHECK_ACK_SEND; |
| I2C1TRN = (i2c_data_p->master_dest_addr << 1) | 0x0; |
| break; |
| case I2C1_CHECK_ACK_SEND: |
| // Check if ACK is received or not |
| if (!I2C1STATbits.ACKSTAT) { |
| // If an ACK is received, send first byte of data |
| uint8_t to_send = i2c_data_p->buffer_in[0]; |
| I2C1TRN = to_send; |
| i2c_data_p->operating_state = I2C1_CHECK_ACK_RESTART; |
| } else { |
| // If a NACK is received, stop transmission and send error |
| i2c_data_p->operating_state = I2C1_STOPPED; |
| I2C1CONbits.PEN = 1; |
| i2c_data_p->return_status = I2C1_SEND_FAIL; |
| } |
| break; |
| case I2C1_CHECK_ACK_RESTART: |
| if (!I2C1STATbits.ACKSTAT) { |
| I2C1CONbits.RSEN = 1; |
| i2c_data_p->operating_state = I2C1_SEND_ADDR_2; |
| } else { |
| // If a NACK is received, stop transmission and send error |
| i2c_data_p->operating_state = I2C1_STOPPED; |
| I2C1CONbits.PEN = 1; |
| i2c_data_p->return_status = I2C1_SEND_FAIL; |
| } |
| break; |
| case I2C1_SEND_ADDR_2: |
| // Send the address with read bit set |
| i2c_data_p->operating_state = I2C1_CHECK_ACK_RECV; |
| I2C1TRN = (i2c_data_p->master_dest_addr << 1) | 0x1; |
| break; |
| case I2C1_CHECK_ACK_RECV: |
| // Check if ACK is received |
| if (!I2C1STATbits.ACKSTAT) { |
| // If an ACK is received, set module to receive 1 byte of data |
| i2c_data_p->operating_state = I2C1_RCV_DATA; |
| I2C1CONbits.RCEN = 1; |
| } else { |
| // If a NACK is received, stop transmission and send error |
| i2c_data_p->operating_state = I2C1_STOPPED; |
| I2C1CONbits.PEN = 1; |
| i2c_data_p->return_status = I2C1_RECV_FAIL; |
| } |
| break; |
| case I2C1_RCV_DATA: |
| // On receive, save byte into buffer |
| // TODO: Handle possible I2C buffer overflow |
| i2c_data_p->buffer_in[i2c_data_p->buffer_in_write_ind] = I2C1RCV; |
| i2c_data_p->buffer_in_write_ind++; |
| if (i2c_data_p->buffer_in_write_ind < i2c_data_p->buffer_in_len) { |
| // If we still need to read, send an ACK to the slave |
| i2c_data_p->operating_state = I2C1_REQ_DATA; |
| I2C1CONbits.ACKDT = 0; // ACK |
| I2C1CONbits.ACKEN = 1; |
| } else { |
| // If we are done reading, send an NACK to the slave |
| i2c_data_p->operating_state = I2C1_SEND_STOP; |
| I2C1CONbits.ACKDT = 1; // NACK |
| I2C1CONbits.ACKEN = 1; |
| } |
| break; |
| case I2C1_REQ_DATA: |
| // Set module to receive one byte of data |
| i2c_data_p->operating_state = I2C1_RCV_DATA; |
| I2C1CONbits.RCEN = 1; |
| break; |
| case I2C1_SEND_STOP: |
| // Send the stop bit |
| i2c_data_p->operating_state = I2C1_STOPPED; |
| I2C1CONbits.PEN = 1; |
| i2c_data_p->return_status = I2C1_RECV_OK; |
| break; |
| case I2C1_STOPPED: |
| i2c_data_p->operating_state = I2C1_IDLE; |
| i2c_data_p->master_status = I2C1_MASTER_IDLE; |
| break; |
| } |
| } |
| } |
| |
| void I2C1_Interrupt_Slave() { |
| // !!WARNING!! THIS CODE DOES -NOT- HAVE ANY ERROR HANDLING !! |
| // TODO: Add error handling to this interrupt function |
| |
| /* The PIC32 family has different slave interrupts than the PIC8 family |
| * Slave mode operations that generate a slave interrupt are: |
| * 1. Detection of a valid device address (including general call) |
| * 2. Reception of data |
| * 3. Request to transmit data |
| */ |
| |
| uint8_t received_data; |
| uint8_t data_read_from_buffer = 0; |
| uint8_t data_written_to_buffer = 0; |
| uint8_t overrun_error = 0; |
| |
| // Clear SSPOV (overflow bit) |
| if (I2C1STATbits.I2COV == 1) { |
| I2C1STATbits.I2COV = 0; |
| overrun_error = 1; |
| i2c_data_p->return_status = I2C1_ERR_OVERRUN; |
| } |
| |
| // Read SPPxBUF if it is full |
| if (I2C1STATbits.RBF == 1) { |
| received_data = I2C1RCV; |
| data_read_from_buffer = 1; |
| } |
| |
| if (!overrun_error) { |
| if (I2C1STATbits.R_W == 0) { |
| // Slave is receiving data |
| i2c_data_p->buffer_in[i2c_data_p->buffer_in_write_ind] = received_data; |
| if (i2c_data_p->buffer_in_write_ind == MAXI2C1BUF - 1) { |
| i2c_data_p->buffer_in_write_ind = 0; |
| } else { |
| i2c_data_p->buffer_in_write_ind++; |
| } |
| if (i2c_data_p->buffer_in_len < MAXI2C1BUF - 1) { |
| i2c_data_p->buffer_in_len++; |
| } |
| i2c_data_p->slave_in_last_byte = received_data; |
| i2c_data_p->return_status = I2C1_RECV_OK; |
| } else { |
| // Slave is returning data |
| if (!i2c_data_p->slave_sending_data) { |
| // If we are not currently sending data, figure out what to reply with |
| if (I2C1_Process_Request(i2c_data_p->slave_in_last_byte)) { |
| // Data exists to be returned, send first byte |
| I2C1TRN = i2c_data_p->buffer_out[0]; |
| data_written_to_buffer = 1; |
| i2c_data_p->buffer_out_ind = 1; |
| i2c_data_p->slave_sending_data = 1; |
| } else { |
| // Unknown request, fill rest of request with 0s |
| I2C1TRN = 0x0; |
| data_written_to_buffer = 1; |
| i2c_data_p->slave_sending_data = 0; |
| i2c_data_p->return_status = I2C1_SEND_FAIL; |
| } |
| } else { |
| // Sending remaining data back to master |
| if (i2c_data_p->buffer_out_ind < i2c_data_p->buffer_out_len) { |
| I2C1TRN = i2c_data_p->buffer_out[i2c_data_p->buffer_out_ind]; |
| data_written_to_buffer = 1; |
| i2c_data_p->buffer_out_ind++; |
| } else { |
| // Nothing left to send, fill rest of request with 0s |
| I2C1TRN = 0x0; |
| data_written_to_buffer = 1; |
| i2c_data_p->slave_sending_data = 0; |
| i2c_data_p->return_status = I2C1_SEND_OK; |
| } |
| } |
| } |
| } |
| |
| // Release the clock stretching bit (if we should) |
| if (data_read_from_buffer || data_written_to_buffer) { |
| // Release the clock |
| if (I2C1CONbits.SCLREL == 0) { |
| I2C1CONbits.SCLREL = 1; |
| } |
| } |
| } |
| |
| /* Returns 0 if I2C module is currently busy, otherwise returns status code */ |
| uint8_t I2C1_Get_Status() { |
| if (i2c_data_p->master_status == I2C1_MASTER_IDLE && |
| i2c_data_p->operating_state == I2C1_IDLE && |
| I2C1STATbits.TBF == 0) { |
| return i2c_data_p->return_status; |
| } else { |
| return 0; |
| } |
| } |
| |
| uint8_t I2C1_Buffer_Len() { |
| return i2c_data_p->buffer_in_len; |
| } |
| |
| /* Returns 0 if I2C module is currently busy, otherwise returns buffer length */ |
| uint8_t I2C1_Read_Buffer(uint8_t *buffer) { |
| uint32_t i = 0; |
| while (i2c_data_p->buffer_in_len != 0) { |
| buffer[i] = i2c_data_p->buffer_in[i2c_data_p->buffer_in_read_ind]; |
| i++; |
| if (i2c_data_p->buffer_in_read_ind == MAXI2C1BUF-1) { |
| i2c_data_p->buffer_in_read_ind = 0; |
| } else { |
| i2c_data_p->buffer_in_read_ind++; |
| } |
| i2c_data_p->buffer_in_len--; |
| } |
| return i; |
| } |
| |
| /* Put data to be returned here */ |
| uint8_t I2C1_Process_Request(uint8_t c) { |
| uint8_t ret = 0; |
| switch (c) { |
| case 0x01: |
| i2c_data_p->buffer_out[0] = 0x12; |
| i2c_data_p->buffer_out_len = 1; |
| ret = 1; |
| break; |
| case 0x02: |
| i2c_data_p->buffer_out[0] = 0x34; |
| i2c_data_p->buffer_out[1] = 0x56; |
| i2c_data_p->buffer_out_len = 2; |
| ret = 1; |
| break; |
| } |
| return ret; |
| } |