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Missing SPI Transaction API methods on Due (SAM3X) #2299

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Merged
merged 4 commits into from
Sep 12, 2014
Merged

Missing SPI Transaction API methods on Due (SAM3X) #2299

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11cf45d
Fix indent and small cosmetic changes
cmaglie Sep 10, 2014
848dd39
[sam] SPI library: added SPI_HAS_EXTENDED_CS_PIN_HANDLING flag
cmaglie Sep 7, 2014
5f88564
[sam] Simplified formula for SPI speed
cmaglie Sep 10, 2014
6a5b82f
[sam] Implementation of SPI multibyte transfer
cmaglie Sep 10, 2014
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82 changes: 67 additions & 15 deletions hardware/arduino/sam/libraries/SPI/SPI.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -62,12 +62,12 @@ void SPIClass::init() {
#define interruptsStatus() __interruptsStatus()
static inline unsigned char __interruptsStatus(void) __attribute__((always_inline, unused));
static inline unsigned char __interruptsStatus(void) {
unsigned int primask, faultmask;
asm volatile ("mrs %0, primask" : "=r" (primask));
if (primask) return 0;
asm volatile ("mrs %0, faultmask" : "=r" (faultmask));
if (faultmask) return 0;
return 1;
unsigned int primask, faultmask;
asm volatile ("mrs %0, primask" : "=r" (primask));
if (primask) return 0;
asm volatile ("mrs %0, faultmask" : "=r" (faultmask));
if (faultmask) return 0;
return 1;
}
#endif

Expand Down Expand Up @@ -182,18 +182,70 @@ byte SPIClass::transfer(byte _pin, uint8_t _data, SPITransferMode _mode) {
d |= SPI_TDR_LASTXFER;

// SPI_Write(spi, _channel, _data);
while ((spi->SPI_SR & SPI_SR_TDRE) == 0)
;
spi->SPI_TDR = d;

// return SPI_Read(spi);
while ((spi->SPI_SR & SPI_SR_RDRF) == 0)
;
d = spi->SPI_RDR;
while ((spi->SPI_SR & SPI_SR_TDRE) == 0)
;
spi->SPI_TDR = d;

// return SPI_Read(spi);
while ((spi->SPI_SR & SPI_SR_RDRF) == 0)
;
d = spi->SPI_RDR;
// Reverse bit order
if (bitOrder[ch] == LSBFIRST)
d = __REV(__RBIT(d));
return d & 0xFF;
return d & 0xFF;
}

void SPIClass::transfer(byte _pin, void *_buf, size_t _count, SPITransferMode _mode) {
if (_count == 0)
return;

uint8_t *buffer = (uint8_t *)_buf;
if (_count == 1) {
*buffer = transfer(_pin, *buffer, _mode);
return;
}

uint32_t ch = BOARD_PIN_TO_SPI_CHANNEL(_pin);
bool reverse = (bitOrder[ch] == LSBFIRST);

// Send the first byte
uint32_t d = *buffer;
if (reverse)
d = __REV(__RBIT(d));
while ((spi->SPI_SR & SPI_SR_TDRE) == 0)
;
spi->SPI_TDR = d | SPI_PCS(ch);

while (_count > 1) {
// Prepare next byte
d = *(buffer+1);
if (reverse)
d = __REV(__RBIT(d));
if (_count == 2 && _mode == SPI_LAST)
d |= SPI_TDR_LASTXFER;

// Read transferred byte and send next one straight away
while ((spi->SPI_SR & SPI_SR_RDRF) == 0)
;
uint8_t r = spi->SPI_RDR;
spi->SPI_TDR = d | SPI_PCS(ch);

// Save read byte
if (reverse)
r = __REV(__RBIT(r));
*buffer = r;
buffer++;
_count--;
}

// Receive the last transferred byte
while ((spi->SPI_SR & SPI_SR_RDRF) == 0)
;
uint8_t r = spi->SPI_RDR;
if (reverse)
r = __REV(__RBIT(r));
*buffer = r;
}

void SPIClass::attachInterrupt(void) {
Expand Down
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