ESP32的spi通信
ESP32的spi通信问题，使用ESP32的spi例程，SPI发送数据时时钟线SCK一直为高电平如下图
数据线的变化是对的，代码在下面
问题相关代码，请勿粘贴截图
#define PIN_NUM_MISO 25
#define PIN_NUM_MOSI 23
#define PIN_NUM_CLK 19
#define PIN_NUM_CS 22
#define PIN_NUM_DC 21
#define PIN_NUM_RST 18
#define PIN_NUM_BCKL 5
void lcd_cmd(spi_device_handle_t spi, const uint8_t cmd)
{
esp_err_t ret;
spi_transaction_t t;
memset(&t, 0, sizeof(t)); //Zero out the transaction
t.length=8; //Command is 8 bits
t.tx_buffer=&cmd; //The data is the cmd itself
t.user=(void*)0; //D/C needs to be set to 0
ret=spi_device_polling_transmit(spi, &t); //Transmit!
assert(ret==ESP_OK); //Should have had no issues.
}
void lcd_spi_pre_transfer_callback(spi_transaction_t *t)
{
int dc=(int)t->user;
gpio_set_level(PIN_NUM_DC, dc);
}
void app_main(void)
{
esp_err_t ret;
spi_device_handle_t spi;
spi_bus_config_t buscfg={
.miso_io_num=PIN_NUM_MISO,
.mosi_io_num=PIN_NUM_MOSI,
.sclk_io_num=PIN_NUM_CLK,
.quadwp_io_num=-1,
.quadhd_io_num=-1,
.max_transfer_sz=PARALLEL_LINES*320*2+8
};
spi_device_interface_config_t devcfg={
#ifdef CONFIG_LCD_OVERCLOCK
.clock_speed_hz=26*1000*1000, //Clock out at 26 MHz
#else
.clock_speed_hz=10*1000*1000, //Clock out at 10 MHz
#endif
.mode=1, //SPI mode 0
.spics_io_num=PIN_NUM_CS, //CS pin
.queue_size=7, //We want to be able to queue 7 transactions at a time
.pre_cb=lcd_spi_pre_transfer_callback, //Specify pre-transfer callback to handle D/C line
};
//Initialize the SPI bus
ret=spi_bus_initialize(LCD_HOST, &buscfg, SPI_DMA_CH_AUTO);
ESP_ERROR_CHECK(ret);
//Attach the LCD to the SPI bus
ret=spi_bus_add_device(LCD_HOST, &devcfg, &spi);
ESP_ERROR_CHECK(ret);
gpio_set_direction(PIN_NUM_DC, GPIO_MODE_OUTPUT);
while(1) {
lcd_cmd(spi, 0x04);
vTaskDelay(pdMS_TO_TICKS(10));
}
}