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#include <xc.h>

#include <plib.h>

#include "defines.h"

#include "SPI1.h"

static SPI1_DATA *spi_data_ptr;

void SPI1_Init(SPI1_DATA *data, void (*rx_callback)(char)) {

    spi_data_ptr = data;

    spi_data_ptr->buffer_out_ind = 0;

    spi_data_ptr->buffer_out_len = 0;

    spi_data_ptr->rx_callback = rx_callback;

    INTDisableInterrupts();

    // Note: FIFO enhanced buffer depth is 4/8/16 for 32/16/8 bit widths

    // Alternative Configuration:

    // The third value is the SPI bitrate which is 1/2 the frequency of the

    //  desired clock frequency. Thus 40Mhz / (20Mhz / 2) = 4.

    // Note: SPI_OPEN_TBE_NOT_FULL should only be used at >10Mhz speeds

//    SpiChnOpen(SPI_CHANNEL1, SPI_OPEN_MSTEN | SPI_OPEN_ENHBUF | SPI_OPEN_TBE_NOT_FULL | SPI_OPEN_RBF_NOT_EMPTY, 4);

//    INTSetVectorPriority(INT_SPI_1_VECTOR, INT_PRIORITY_LEVEL_6);

//    INTSetVectorSubPriority(INT_SPI_1_VECTOR, INT_SUB_PRIORITY_LEVEL_1);

//    INTClearFlag(INT_SPI1E);

//    INTClearFlag(INT_SPI1TX);

//    INTClearFlag(INT_SPI1RX);

    // FSCK = FPB / (2 * (SPIxBRG + 1))

    IEC0CLR     = 0x03800000;   // Disable all SPI interrupts

    SPI1CON     = 0;            // Stops and resets the SPI1.

    int tmp     = SPI1BUF;      // Clears the receive buffer

    IFS0CLR     = 0x03800000;   // Clear any existing event

    IPC5CLR     = 0x1F000000;   // Clear the priority

    IPC5SET     = 0x19000000;   // Set IPL=6, Subpriority 1

    SPI1BRG     = 0x1;          // Use FPB/4 clock frequency

    SPI1STATCLR = 0x40;         // Clear the Overflow

#ifndef SPI_WRITE_ONLY

    IEC0SET = 0x01800000;       // Enable RX and Error interrupts

#endif

    // Enhanced buffer, SPI on, 8 bits transfer, SMP=1, Master mode

    // SPIxTXIF set on buffer empty, SPIxRXIF set on buffer not empty

    SPI1CON     = 0x18225;

    INTEnableInterrupts();

}

int SPI1_Write(char *array, int length, void (*tx_callback)(void)) {

    spi_data_ptr->tx_callback = tx_callback;

    if (length > SPI1_BUFFER_OUT_SIZE)

        return 0;

    if (spi_data_ptr->buffer_out_len != 0)

        return 0;

    // Put the data to send into the outbound buffer

    spi_data_ptr->buffer_out_len = length;

    spi_data_ptr->buffer_out_ind = length-1;

    int i;

    for (i = 0; i < length; i++) {

        spi_data_ptr->buffer_out[i] = array[i];

    }

    IEC0SET = 0x02000000; // Enable TX interrupt

    return 1;

}

void __ISR(_SPI_1_VECTOR, ipl6) __SPI_1_Interrupt_Handler(void) {

#ifndef SPI_WRITE_ONLY

    // Process SPI1 error flag

    if (IFS0bits.SPI1EIF) {

        // Clear the receive overflow bit if it is set

        if (SPI1STATbits.SPIROV) {

            SPI1STATbits.SPIROV = 0;

        }

        IFS0CLR = 0x00800000; // Clear the error flag

    }

    // Process SPI1 receive flag

    if (IFS0bits.SPI1RXIF) {

        int i;

        // Read the data received from the last transfer

        int rxBufferCount = SPI1STATbits.RXBUFELM;

        for (i = 0; i < rxBufferCount; i++) {

            char c = SPI1BUF;

            // Call the RX callback function on the received data

            if (spi_data_ptr->rx_callback != NULL)

                (*spi_data_ptr->rx_callback)(c);

        }

        IFS0CLR = 0x01000000; // Clear the RX flag

    }

#endif

    // Process SPI1 transmit flag

    if (IFS0bits.SPI1TXIF && IEC0bits.SPI1TXIE) {

        int i;

        // Disable the transmit interrupt if all data has been sent

        if (spi_data_ptr->buffer_out_len == 0) {

            IEC0CLR=0x02000000;

            if (spi_data_ptr->tx_callback != NULL)

                (*spi_data_ptr->tx_callback)();

        } else {

            // Start transmitting the data in the buffer

            int txBufferFree = 16 - SPI1STATbits.TXBUFELM;

            if (spi_data_ptr->buffer_out_len > txBufferFree) {

                for (i = 0; i < txBufferFree; i++) {

                    SPI1BUF = spi_data_ptr->buffer_out[spi_data_ptr->buffer_out_ind];

                    spi_data_ptr->buffer_out_ind--;

                }

                spi_data_ptr->buffer_out_len -= txBufferFree;

            } else {

                for (i = 0; i < spi_data_ptr->buffer_out_len; i++) {

                    SPI1BUF = spi_data_ptr->buffer_out[spi_data_ptr->buffer_out_ind];

                    spi_data_ptr->buffer_out_ind--;

                }

                spi_data_ptr->buffer_out_len = 0;

            }

        }

        IFS0CLR = 0x02000000; // Clear the TX flag

    }

}