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#include "DEFINES.h"
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#include "EUSART.h"
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#include "INTERRUPTS.h"
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static volatile uint8_t txBuffer[UART_TX_BUFFER_SIZE];
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static volatile uint8_t txBufferSize = 0;
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static volatile uint8_t txBufferIndex = 0;
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static volatile uint8_t rxBuffer[UART_RX_BUFFER_SIZE];
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static volatile uint8_t rxBufferSize = 0;
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static volatile uint8_t rxBufferIndex = 0;
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void UART_Init() {
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UART_TX_TRIS = 0;
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UART_RX_TRIS = 1;
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BAUDCONbits.BRG16 = 0; // 8-bit baud rate generation
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SPBRG = 64; // Baud rate of 19.2k
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TXSTAbits.BRGH = 1; // High speed mode
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TXSTAbits.SYNC = 0; // Async mode
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RCSTAbits.SPEN = 1; // Serial port enable
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TXSTAbits.TX9 = 0; // 8 bit transmission
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RCSTAbits.RX9 = 0; // 8 bit reception
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TXSTAbits.TXEN = 1; // Transmission enabled
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RCSTAbits.CREN = 1; // Reception enabled
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PIE1bits.TXIE = 0; // TX interrupt starts disabled
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PIE1bits.RCIE = 1; // RX interrupt starts enabled
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}
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void UART_Write(uint8_t *msg, uint8_t length) {
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// Check to make sure there is enough space in buffer for message
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length = (length > UART_TX_BUFFER_SIZE) ? UART_TX_BUFFER_SIZE : length;
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// Wait for previous message to finish sending
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while (PIE1bits.TXIE);
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txBufferSize = length;
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txBufferIndex = 1;
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for (uint8_t i = 0; i < length; i++) {
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txBuffer[i] = msg[i];
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}
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TXREG = txBuffer[0];
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PIE1bits.TXIE = 1;
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}
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void UART_TX_Interrupt_Handler() {
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if (txBufferIndex != txBufferSize) {
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// Transmit next byte in the buffer
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TXREG = txBuffer[txBufferIndex];
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txBufferIndex++;
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} else {
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// Wait for last byte to finish sending
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while (!TXSTAbits.TRMT);
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PIE1bits.TXIE = 0;
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txBufferSize = 0;
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txBufferIndex = 0;
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}
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}
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void UART_RX_Interrupt_Handler() {
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if (PIR1bits.RCIF) {
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uint8_t c = RCREG;
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// Store received byte into buffer and increment write location
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rxBuffer[rxBufferIndex] = c;
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if (rxBufferIndex == UART_RX_BUFFER_SIZE - 1) {
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rxBufferIndex = 0;
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} else {
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rxBufferIndex++;
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}
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// Increment received byte count
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if (rxBufferSize < UART_RX_BUFFER_SIZE) {
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rxBufferSize++;
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}
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}
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// If UART overrun is detected, reset module
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if (RCSTAbits.OERR) {
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TXSTAbits.TXEN = 0;
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RCSTAbits.CREN = 0;
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RCSTAbits.CREN = 1;
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}
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}
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uint8_t UART_Read(uint8_t *buffer) {
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// Return values in RX buffer
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uint8_t size = rxBufferSize;
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for (uint8_t i = 0; i < size; i++) {
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buffer[i] = rxBuffer[i];
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}
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return size;
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}
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void UART_Reset_RX() {
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rxBufferIndex = 0;
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rxBufferSize = 0;
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}
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