I would like to create SPI clock timings using the following documents.
https://infocenter.nordicsemi.com/index.jsp?topic=%2Fps_nrf52840%2Fspim.html&anchor=topic
1. CSN pin moves from High -> Low
2. Data Set
3. Data recognition when clock data is moved high
The setup values are as follows.
SCNPOL = 1
CPOL = 0
CPHA = 0
The waveform (example) I want to operate is as follows.
But I have this problem.
When the clock goes up, the data goes up at the same time.
The source code is as follows.
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#include "nrf_drv_spi.h"
#include "app_util_platform.h"
#include "nrf_gpio.h"
#include "nrf_delay.h"
#include "boards.h"
#include "app_error.h"
#include <string.h>
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
#define SPI_INSTANCE 0 /**< SPI instance index. */
static const nrf_drv_spi_t spi = NRF_DRV_SPI_INSTANCE(SPI_INSTANCE); /**< SPI instance. */
static volatile bool spi_xfer_done; /**< Flag used to indicate that SPI instance completed the transfer. */
#define TEST_STRING "No"
static uint8_t m_tx_buf[] = TEST_STRING; /**< TX buffer. */
static uint8_t m_rx_buf[sizeof(TEST_STRING) + 1]; /**< RX buffer. */
static const uint8_t m_length = sizeof(m_tx_buf); /**< Transfer length. */
static uint8_t send_buf[3] = {0,0,0};
static uint8_t recived_buf[4];
static const uint8_t send_length = sizeof(send_buf);
/**
* @brief SPI user event handler.
* @param event
*/
void spi_event_handler(nrf_drv_spi_evt_t const * p_event,
void * p_context)
{
spi_xfer_done = true;
NRF_LOG_INFO("Transfer completed.");
if (recived_buf[0] != 0)
{
NRF_LOG_INFO(" Received:");
NRF_LOG_HEXDUMP_INFO(recived_buf, strlen((const char *)recived_buf));
}
}
void spi_send(char addr, char Data_h, char Data_l){
// Reset rx buffer and transfer done flag
memset(recived_buf, 0, send_length);
spi_xfer_done = false;
send_buf[2] = addr;
send_buf[0] = Data_h;
send_buf[1] = Data_l;
nrf_drv_spi_transfer(&spi, send_buf, send_length, recived_buf, send_length);
while (!spi_xfer_done)
{
__WFE();
}
NRF_LOG_FLUSH();
}
int main(void)
{
bsp_board_init(BSP_INIT_LEDS);
APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
NRF_LOG_DEFAULT_BACKENDS_INIT();
nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
spi_config.ss_pin = SPI_SS_PIN;
spi_config.miso_pin = SPI_MISO_PIN;
spi_config.mosi_pin = SPI_MOSI_PIN;
spi_config.sck_pin = SPI_SCK_PIN;
APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL));
NRF_LOG_INFO("SPI example started.");
while (1)
{
spi_send(0x11,0x00,0x7F);
//APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, m_length));
bsp_board_led_invert(BSP_BOARD_LED_0);
nrf_delay_ms(200);
}
}
