NRF51822之SPI

 1 /**@brief Function for initializing a SPI master driver.
 2  *
 3  * @param[in] p_instance    Pointer to SPI master driver instance.
 4  */
 5 static void spi_master_init(nrf_drv_spi_t const * p_instance)
 6 {
 7     uint32_t err_code = NRF_SUCCESS;
 8
 9     nrf_drv_spi_config_t config =
10     {
11
12         .irq_priority = APP_IRQ_PRIORITY_LOW,
13         .orc          = 0x80,
14         .frequency    = NRF_DRV_SPI_FREQ_1M,
15         .mode         = NRF_DRV_SPI_MODE_0,
16         .bit_order    = NRF_DRV_SPI_BIT_ORDER_MSB_FIRST,
17     };
18
19     #if (SPI0_ENABLED == 1)
20     if (p_instance == &m_spi_master_0)
21     {
22         config.ss_pin   = SPIM0_SS_PIN,
23         config.sck_pin  = SPIM0_SCK_PIN;
24         config.mosi_pin = SPIM0_MOSI_PIN;
25         config.miso_pin = SPIM0_MISO_PIN;
26         err_code = nrf_drv_spi_init(p_instance,
27                                     &config,
28                                     spi_master_0_event_handler);
29     }
30     else
31     #endif // (SPI0_ENABLED == 1)
32
33     APP_ERROR_CHECK(err_code);
34 }

 1 uint8_t  spi_write_reg(uint8_t ucRegAddr, uint8_t ucRegVal)
 2 {
 3     uint8_t buf[2];
 4     uint32_t err_code;
 5
 6     spi_xfer_done = false;
 7
 8     buf[0] = ucRegAddr<<1;
 9     buf[1] = ucRegVal;
10
11     err_code = nrf_drv_spi_transfer(&m_spi_master_0, buf, 2, NULL, 0);
12     APP_ERROR_CHECK(err_code);
13
14     while (!spi_xfer_done)
15     {
16         __WFE();
17     }
18     return true;
19 }
20
21
22 uint8_t spi_read_reg(uint8_t ucRegAddr)
23 {
24     uint8_t buf[2];
25     uint8_t rx[2];
26     uint32_t err_code;
27
28     spi_xfer_done = false;
29
30     buf[0] =( ucRegAddr<<1 ) | 0x80;
31     buf[1] = 0x00;
32
33     err_code = nrf_drv_spi_transfer(&m_spi_master_0,buf,2,rx,2);
34     APP_ERROR_CHECK(err_code);
35
36     while(!spi_xfer_done)
37     {
38         __WFE();
39     }
40
41     return rx[1];
42 }

现在我们对spi_write_reg(uint8_t ucRegAddr, uint8_t ucRegVal)进行测试

更据我们的代码在Saleae Logic 1.1.16C中进行设置如下图所示

什么看不懂上面的配置？请右转补课 http://www.cnblogs.com/libra13179/p/5740716.html

spi_write_reg(0x00,0x00)

spi_write_reg(0x01,0x02)  故意留下思考？为何下图显示是0X02而不是0x01，有什么作用呢？