I work with SAM3X8E microcontroller (datasheet : https://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-11057-32-bit-Cortex-M3-Microcontroller-SAM3X-SAM3A_Datasheet.pdf, page 676 to 707 for SPI)
I want to make a multi transfer bytes thanks to SPI Bus. I initialize my CS as a GPIO to control it manually. My CS, MOSI and CLK works well but my MISO always return me 0...
This is some screen of the signals :
CS :
This is my initialization of the SPI Bus :
/* Configure an SPI peripheral. */
spi_enable_clock(SPI0);
spi_disable(SPI0);
spi_reset(SPI0);
spi_set_master_mode(SPI0);
spi_disable_mode_fault_detect(SPI0);
spi_set_peripheral_chip_select_value(SPI0, SPI_CHIP_SEL);
/* data samples on rising edge because Polarity = Phase = 0 */
spi_set_clock_polarity(SPI0, SPI_CHIP_SEL, SPI_CLK_POLARITY);
spi_set_clock_phase(SPI0, SPI_CHIP_SEL, SPI_CLK_PHASE);
spi_set_bits_per_transfer(SPI0, SPI_CHIP_SEL, SPI_CSR_BITS_8_BIT);
spi_set_baudrate_div(SPI0, SPI_CHIP_SEL, (sysclk_get_peripheral_hz() / gs_ul_spi_clock));
SPI0->SPI_CSR[0] |= SPI_CSR_CSAAT;
spi_enable(SPI0);This is the code of my multi tranfer bytes :
uint8_t ftData8;
EVE_cs_set(); //CS at 0
spi_transmit_32(...); //Make 4 spi_transmit(...)
ftData8 = spi_receive(0x00); /* read data byte by sending another dummy byte */
EVE_cs_clear(); //CS at 1
return ftData8; /* return byte read */And this is the code of my function spi_transmit(...) :
static inline uint8_t spi_transmit(uint8_t data)
{
while ((SPI0->SPI_SR & SPI_SR_TDRE) == 0);
spi_write(SPI0, data, SPI_CHIP_SEL, 0);
while ((SPI0->SPI_SR & SPI_SR_RDRF) == 0);
uint8_t data_read, Chip_Sel_read;
spi_read(SPI0, &data_read, &Chip_Sel_read);
return data_read;
}Can you see where is the problem ?
PS :
I have a screen of a workwell MISO (in the same case) if you want to see how it's should looks like :
Hi, I have some news!
I thought the problem was with my SPI or PIN setup but after many changes it didn't do anything.
I reworked my functions and there I have a result (which does not work yet but encouraging).
Here is my MISO signal:
We can see that there is a response from the screen. However, the 8-bit multi transfers are maybe a little too stuck (no cut between 5 transfers) and my CS resets to 1 before the end of my multi transfer.
Here is my spi_trasnmit (data) function:
static inline void spi_transmit(uint8_t data)
{
while ((SPI0->SPI_SR & SPI_SR_TXEMPTY) == 1);
spi_write(SPI0, data, SPI_CHIP_SEL, 0);
while ((SPI0->SPI_SR & SPI_SR_TDRE) == 1);
}Here is my spi_receive (data) function:
{
uint8_t data_read, Chip_Sel_read;
spi_transmit(data);
while((SPI0->SPI_SR & SPI_SR_RDRF) == 0);
spi_read(SPI0, &data_read, &Chip_Sel_read);
return data_read;
}and here is the function I call to do my 5 byte transfer:
uint8_t ftData8;
EVE_cs_set(); //CS at 0
spi_transmit_32(...); //Make 4 spi_transmit(...)
ftData8 = spi_receive(0x00); /* read data byte by sending another dummy byte */
EVE_cs_clear(); //CS at 1
return ftData8; /* return byte read */