/**
* DMA based block transfer to and from SPI devices
* For RX, a buffer full of 0xFF must be transmitted to create the clock
* For TX, an empty RX buffer must be provided for dummy RX data.
* This only works with fixed chip-select
* @param outbuf pointer to TX buffer
* @param inbuf pointer to RX buffer
* @param length Amount of bytes to transfer
* @return return 0 if the SPI device was not ready, 1 otherwise.
*/
int spi_dma_transfer(spi_chip_t * spi_chip, uint8_t * outbuf, uint8_t * inbuf, uint32_t length) {
unsigned int bytes_done = 0;
/* Wait for SPI to become ready */
if (!spi_busy_wait_tx()) {
xSemaphoreGive(spi_chip->spi_dev->lock);
return 0;
}
/* Set chip select mode */
if (current_chip != spi_chip) {
spi_setup_chip(spi_chip);
current_chip = spi_chip;
}
/* Select chip */
SPI_MR = (SPI_MR & ~SPI_MR_PCS_MASK) | (spi_chip->cs << SPI_MR_PCS_BIT);
/* Enable PDC interrupt on SPI */
SPI_IER = SPI_IER_TEND;
/* Loop here if length is larger than 0xFFFF */
while (bytes_done < length) {
/* Start PDC Transfer */
if (inbuf != NULL)
PDC_MPR6 = (uint32_t) &inbuf[bytes_done];
PDC_MPR7 = (uint32_t) &outbuf[bytes_done];
/* Number of bytes to read - truncated to 64k */
if ((length - bytes_done) > 0x0000FFFF) {
if (inbuf != NULL)
PDC_TCR6 = 0x0000FFFF;
PDC_TCR7 = 0x0000FFFF;
bytes_done += 0x0000FFFF;
} else {
if (inbuf != NULL)
PDC_TCR6 = length - bytes_done;
PDC_TCR7 = length - bytes_done;
bytes_done = length;
}
/* Wait for the DMA finish signal */
xSemaphoreTake(spi_sem_dma, 1*configTICK_RATE_HZ);
}
/* Disable PDC interrupt on SPI */
SPI_IER = SPI_IER_TEND;
return 1;
}
/* reference lm70 */
void accel_sensor_spi_setup_cs(spi_dev_t * spi_dev, spi_chip_t * spi_chip, uint8_t cs) {
spi_chip->spi_dev = spi_dev; // A pointer to the physical device SPI0
spi_chip->baudrate = 1000000; // This is only initial baud rate, it will be increased by the driver
spi_chip->spi_mode = 3; // SPI mode
spi_chip->bits = 16; // Default value for transferring bytes
spi_chip->cs = cs; // The chip select number
spi_chip->reg = cs/4; // The chip select register, The register bank to use
spi_chip->stay_act = 0; // Should the chip-select stay active until next SPI transmission? //reference lm70
spi_chip->spck_delay = 4; // Delay
spi_chip->trans_delay = 60; // Delay
spi_setup_chip(spi_chip);
}
/**
* Send a byte via SPI
* @param spi_chip The chip to send to
* @param 16 bits to send
*/
void spi_write(spi_chip_t * spi_chip, uint16_t byte) {
spi_busy_wait_tx();
/* Re-initialise new chip in new mode */
if (current_chip != spi_chip) {
spi_setup_chip(spi_chip);
current_chip = spi_chip;
}
/* Select chip */
SPI_MR = (SPI_MR & ~SPI_MR_PCS_MASK) | (spi_chip->cs << SPI_MR_PCS_BIT);
SPI_TDR = byte;
}
