0,0 → 1,151 |
#include "defines.h" |
#include "SPI4.h" |
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static SPI4_DATA *spi_data_ptr; |
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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; |
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INTDisableInterrupts(); |
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// Note: FIFO enhanced buffer depth is 4/8/16 for 32/16/8 bit widths |
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// FSCK = FPB / (2 * (SPIxBRG + 1)) |
IEC1CLR = 0x00000700; // Disable all SPI interrupts |
SPI4CON = 0; // Stops and resets the SPI4. |
uint32_t 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 |
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// Enhanced buffer, SPI on, 8 bits transfer, SMP=1, Master mode |
// SPIxTXIF set on buffer empty, SPIxRXIF set on buffer not empty |
SPI4CON = 0x18225; |
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INTEnableInterrupts(); |
} |
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uint8_t SPI4_Read(uint32_t length, void (*rx_callback)(uint8_t, uint8_t *)) { |
spi_data_ptr->rx_callback = rx_callback; |
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// Ensure that the receiving buffer is large enough |
if (length > SPI4_BUFFER_IN_SIZE) |
return 0; |
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// Ensure that no previous transactions are in progress |
if (spi_data_ptr->buffer_in_len != 0) |
return 0; |
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spi_data_ptr->write_blank = 1; |
spi_data_ptr->buffer_in_len = length; |
spi_data_ptr->buffer_in_ind = 0; |
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SPI4_Write(NULL, length, NULL); |
return 1; |
} |
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uint8_t SPI4_Write(uint8_t *array, uint32_t length, void (*tx_callback)(void)) { |
spi_data_ptr->tx_callback = tx_callback; |
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// 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; |
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// Ensure that no previous transactions are in progress |
if (spi_data_ptr->buffer_out_len != 0) |
return 0; |
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// Put the data to send into the outbound buffer |
spi_data_ptr->buffer_out_len = length; |
spi_data_ptr->buffer_out_ind = 0; |
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// Copy only if we are actually going to transmit data |
if (!spi_data_ptr->write_blank) { |
int32_t i; |
for (i = 0; i < length; i++) { |
spi_data_ptr->buffer_out[i] = array[i]; |
} |
} |
IEC1SET = 0x00000400; // Enable TX interrupt |
return 1; |
} |
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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 |
} |
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// Process SPI4 receive flag |
if (IFS1bits.SPI4RXIF) { |
uint32_t i; |
// Read the data received from the last transfer |
uint32_t rxBufferCount = SPI4STATbits.RXBUFELM; |
for (i = 0; i < rxBufferCount; i++) { |
int8_t 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 |
} |
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// Process SPI4 transmit flag |
if (IFS1bits.SPI4TXIF && IEC1bits.SPI4TXIE) { |
int32_t 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 |
int32_t 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 |
} |
} |