| 0,0 → 1,153 |
|---|
| #include <xc.h> |
| #include <plib.h> |
| #include "defines.h" |
| #include "SPI4.h" |
| |
| static SPI4_DATA *spi_data_ptr; |
| |
| void SPI4_Init(SPI4_DATA *data) { |
| spi_data_ptr = data; |
| spi_data_ptr->buffer_out_ind = 0; |
| spi_data_ptr->buffer_out_len = 0; |
| spi_data_ptr->buffer_in_ind = 0; |
| spi_data_ptr->buffer_in_len = 0; |
| spi_data_ptr->write_blank = 0; |
| |
| INTDisableInterrupts(); |
| |
| // Note: FIFO enhanced buffer depth is 4/8/16 for 32/16/8 bit widths |
| |
| // FSCK = FPB / (2 * (SPIxBRG + 1)) |
| IEC1CLR = 0x00000700; // Disable all SPI interrupts |
| SPI4CON = 0; // Stops and resets the SPI4. |
| int tmp = SPI4BUF; // Clears the receive buffer |
| IFS1CLR = 0x00000700; // Clear any existing event |
| IPC8CLR = 0x0000001F; // Clear the priority |
| IPC8SET = 0x0000001A; // Set IPL=6, Subpriority 2 |
| SPI4BRG = 0x4; // Use FPB/10 clock frequency |
| SPI4STATCLR = 0x40; // Clear the Overflow |
| IEC1SET = 0x00000300; // Enable RX and Error interrupts |
| |
| // Enhanced buffer, SPI on, 8 bits transfer, SMP=1, Master mode |
| // SPIxTXIF set on buffer empty, SPIxRXIF set on buffer not empty |
| SPI4CON = 0x18225; |
| |
| INTEnableInterrupts(); |
| } |
| |
| int SPI4_Read(int length, void (*rx_callback)(char, char *)) { |
| spi_data_ptr->rx_callback = rx_callback; |
| |
| // Ensure that the receiving buffer is large enough |
| if (length > SPI4_BUFFER_IN_SIZE) |
| return 0; |
| |
| // Ensure that no previous transactions are in progress |
| if (spi_data_ptr->buffer_in_len != 0) |
| return 0; |
| |
| spi_data_ptr->write_blank = 1; |
| spi_data_ptr->buffer_in_len = length; |
| spi_data_ptr->buffer_in_ind = 0; |
| |
| SPI4_Write(NULL, length, NULL); |
| return 1; |
| } |
| |
| int SPI4_Write(char *array, int length, void (*tx_callback)(void)) { |
| spi_data_ptr->tx_callback = tx_callback; |
| |
| // We only care about the transmit length if we are sending data |
| if (length > SPI4_BUFFER_OUT_SIZE && !spi_data_ptr->write_blank) |
| return 0; |
| |
| // Ensure that no previous transactions are in progress |
| 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 = 0; |
| |
| // Copy only if we are actually going to transmit data |
| if (!spi_data_ptr->write_blank) { |
| int i; |
| for (i = 0; i < length; i++) { |
| spi_data_ptr->buffer_out[i] = array[i]; |
| } |
| } |
| IEC1SET = 0x00000400; // Enable TX interrupt |
| return 1; |
| } |
| |
| void __ISR(_SPI_4_VECTOR, ipl6) __SPI_4_Interrupt_Handler(void) { |
| // Process SPI4 error flag |
| if (IFS1bits.SPI4EIF) { |
| // Clear the receive overflow bit if it is set |
| if (SPI4STATbits.SPIROV) { |
| SPI4STATbits.SPIROV = 0; |
| } |
| IFS1CLR = 0x00000100; // Clear the error flag |
| } |
| |
| // Process SPI4 receive flag |
| if (IFS1bits.SPI4RXIF) { |
| int i; |
| // Read the data received from the last transfer |
| int rxBufferCount = SPI4STATbits.RXBUFELM; |
| for (i = 0; i < rxBufferCount; i++) { |
| char c = SPI4BUF; |
| // Put the received data into the buffer |
| if (spi_data_ptr->buffer_in_len != 0) { |
| spi_data_ptr->buffer_in[spi_data_ptr->buffer_in_ind] = c; |
| spi_data_ptr->buffer_in_ind++; |
| // If done acquiring requested length, reset |
| if (spi_data_ptr->buffer_in_ind == spi_data_ptr->buffer_in_len) { |
| // Call the RX callback function on the received data |
| if (spi_data_ptr->rx_callback != NULL) |
| (*spi_data_ptr->rx_callback)(spi_data_ptr->buffer_in_len, spi_data_ptr->buffer_in); |
| spi_data_ptr->buffer_in_len = 0; |
| } |
| } |
| } |
| IFS1CLR = 0x00000200; // Clear the RX flag |
| } |
| |
| // Process SPI4 transmit flag |
| if (IFS1bits.SPI4TXIF && IEC1bits.SPI4TXIE) { |
| int i; |
| // Disable the transmit interrupt if all data has been sent |
| if (spi_data_ptr->buffer_out_len == 0) { |
| IEC1CLR=0x00000400; |
| spi_data_ptr->write_blank = 0; |
| // Call the TX callback function at end of transmission |
| if (spi_data_ptr->tx_callback != NULL) |
| (*spi_data_ptr->tx_callback)(); |
| } else { |
| // Start transmitting the data in the buffer |
| int txBufferFree = 16 - SPI4STATbits.TXBUFELM; |
| if (spi_data_ptr->buffer_out_len > txBufferFree) { |
| for (i = 0; i < txBufferFree; i++) { |
| if (spi_data_ptr->write_blank) { |
| SPI4BUF = 0x00; |
| } else { |
| SPI4BUF = 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++) { |
| if (spi_data_ptr->write_blank) { |
| SPI4BUF = 0x00; |
| } else { |
| SPI4BUF = spi_data_ptr->buffer_out[spi_data_ptr->buffer_out_ind]; |
| spi_data_ptr->buffer_out_ind++; |
| } |
| } |
| spi_data_ptr->buffer_out_len = 0; |
| } |
| } |
| IFS1CLR = 0x00000400; // Clear the TX flag |
| } |
| } |