概念先知道
- SPI：四根线的全双工串行总线——MOSI（主机发）、MISO（主机收）、SCLK（时钟）、CS（片选）。
- 主从模式：主机产生时钟并决定通信节奏；例程以主机模式运行，自测时把 MOSI 与 MISO 短接即可回环。
- SPI 模式（MODE3）：时钟极性（CPOL）与相位（CPHA）的组合，通信双方必须一致；例程用 MODE3、MSB 先发。
例程功能简介
本页对应博流官方 SDK 的 spi_poll 例程（examples/peripherals/spi/spi_poll），演示 SPI 主机查询模式收发：
- SPI 主机模式，频率 1MHz、模式 3（
SPI_MODE3）、MSB 先发、8 位数据宽度起步； - 依次以 8/16/24/32 位宽度发送递增数据，并读回数据校验（自测时把 MOSI 与 MISO 短接即可回环）；
- 每组宽度测试通过后打印
spi poll send xx-bit test success!。 - 同族例程（
examples/peripherals/spi/）：spi_dma（DMA 收发）、spi_int（中断收发）、spi_flash（SPI Flash）。
操作步骤
硬件准备
例程以 SPI 主机模式运行（SPI_CASE_SELECT 为 0）。自测最简单的方式：把开发板 SPI0 的 MOSI 与 MISO 短接（共地），主机发出的数据会从 MISO 回读；有 SPI 从机设备时也可以接从机测试。
进入例程目录
在终端进入 SDK 的 SPI 例程目录（前提：已按快速开始（Linux）或Windows搭建好环境）：
cd examples/peripherals/spi/spi_poll编译工程
执行编译命令。Ai-M62（BL616）与 Ai-M61（BL618）同属一个系列，统一填写引脚最少的 bl616 即可：
make CHIP=bl616 BOARD=bl616dk烧录固件
用 USB 线连接开发板，按住 BOOT 键（Ai-M61-32S-Kit 为 IO2）不放、短按 EN/RST 进入下载模式，然后执行烧录（把串口号换成实际值）：
make flash CHIP=bl616 COMX=/dev/ttyUSB0运行验证
打开串口助手（波特率 2000000）。例程依次以 8/16/24/32 位数据宽度执行查询发送，自测回环时每组都会打印 data check success 和 spi poll send xx-bit test success!。
代码执行流程
例程从启动到运行的完整流程如下（图中的循环箭头表示反复执行）：
例程调用的 API 介绍
bflb_spi_init(spi, config)
初始化 SPI 外设。struct bflb_spi_config_s 中：
freq：时钟频率，主机例程1MHzrole：角色，SPI_ROLE_MASTER（主机）/SPI_ROLE_SLAVE（从机）mode：SPI 模式，SPI_MODE3data_width：数据宽度，SPI_DATA_WIDTH_8BITbit_order：位序，SPI_BIT_MSBbyte_order：字节序，SPI_BYTE_LSB
参数：
spi：SPI 设备句柄（bflb_device_get_by_name("spi0")）config：配置结构体指针
返回值：成功返回 0；失败返回负值错误码
bflb_spi_feature_control(spi, cmd, arg)
动态调整 SPI 特性，例程用 SPI_CMD_SET_DATA_WIDTH 切换数据宽度、SPI_CMD_SET_CS_INTERVAL 设置片选间隔。
参数：
spi：SPI 设备句柄cmd：命令，SPI_CMD_SET_DATA_WIDTH/SPI_CMD_SET_CS_INTERVALarg：命令参数，如SPI_DATA_WIDTH_16BIT
返回值：成功返回 0；失败返回负值错误码
bflb_spi_poll_exchange(spi, tx, rx, len)
批量收发：把 tx 缓冲区数据发送出去，同时把接收数据写入 rx 缓冲区。
参数：
spi：SPI 设备句柄tx：发送缓冲区rx：接收缓冲区len：字节数
返回值：成功返回 0；失败返回负值错误码
完整代码
以下为 spi_poll/main.c 完整源码，与官方示例（examples/peripherals/spi/spi_poll）一致；点灯引脚已适配 Ai-M61/62-32S-Kit 板载 RGB 灯，默认折叠，点击展开：
📜 点击展开 spi_poll/main.c 完整代码
c
#include "bflb_mtimer.h"
#include "bflb_spi.h"
#include "board.h"
#define SPI_MASTER_CASE 0
#define SPI_SLAVE_CASE 1
#define SPI_CASE_SELECT SPI_MASTER_CASE
#define BUFF_LEN (8 * 1024)
uint32_t tx_buff[BUFF_LEN / 4];
uint32_t rx_buff[BUFF_LEN / 4];
struct bflb_device_s *spi0;
/* poll test func */
int bflb_spi_poll_test(uint32_t data_width)
{
uint32_t data_mask;
uint32_t *p_tx = (uint32_t *)tx_buff;
uint32_t *p_rx = (uint32_t *)rx_buff;
switch (data_width) {
case SPI_DATA_WIDTH_8BIT:
data_mask = 0x000000FF;
break;
case SPI_DATA_WIDTH_16BIT:
data_mask = 0x0000FFFF;
break;
case SPI_DATA_WIDTH_24BIT:
data_mask = 0x00FFFFFF;
break;
case SPI_DATA_WIDTH_32BIT:
data_mask = 0xFFFFFFFF;
break;
default:
printf("data_width err\r\n");
return -1;
break;
}
/* data init */
for (uint16_t i = 0; i < BUFF_LEN / 4; i++) {
p_tx[i] = i;
p_rx[i] = 0;
}
/* set data width */
bflb_spi_feature_control(spi0, SPI_CMD_SET_DATA_WIDTH, data_width);
/* send data */
for (uint16_t i = 0; i < BUFF_LEN / 4; i++) {
p_rx[i] = bflb_spi_poll_send(spi0, p_tx[i]);
#if (SPI_CASE_SELECT == SPI_MASTER_CASE)
bflb_mtimer_delay_us(10); /* delay for slave device prepare ok */
#endif
}
/* check data */
for (uint16_t i = 0; i < BUFF_LEN / 4; i++) {
if (p_rx[i] != (p_tx[i] & data_mask)) {
printf("data error, data[%d]:tx 0x%08lX, rx 0x%08lX\r\n", i, p_tx[i], p_rx[i]);
return -1;
}
}
printf("data check success\r\n");
return 0;
}
/* poll_exchange test func */
int bflb_spi_poll_exchange_test(uint32_t data_width)
{
void *p_tx = (uint32_t *)tx_buff;
void *p_rx = (uint32_t *)rx_buff;
/* data init */
switch (data_width) {
case SPI_DATA_WIDTH_8BIT:
for (uint16_t i = 0; i < BUFF_LEN; i++) {
((uint8_t *)p_tx)[i] = i;
((uint8_t *)p_rx)[i] = 0;
}
break;
case SPI_DATA_WIDTH_16BIT:
for (uint16_t i = 0; i < BUFF_LEN / 2; i++) {
((uint16_t *)p_tx)[i] = i << 0;
((uint16_t *)p_rx)[i] = 0;
}
break;
case SPI_DATA_WIDTH_24BIT:
for (uint16_t i = 0; i < BUFF_LEN / 4; i++) {
((uint32_t *)p_tx)[i] = ((i << 0) | i) & 0x00FFFFFF;
((uint32_t *)p_rx)[i] = 0;
}
break;
case SPI_DATA_WIDTH_32BIT:
for (uint16_t i = 0; i < BUFF_LEN / 4; i++) {
((uint32_t *)p_tx)[i] = (i << 0) | i;
((uint32_t *)p_rx)[i] = 0;
}
break;
default:
return -1;
break;
}
/* set data width */
bflb_spi_feature_control(spi0, SPI_CMD_SET_DATA_WIDTH, data_width);
/* send data */
printf("spi poll exchange width %ld, len %d\r\n", data_width, BUFF_LEN);
bflb_spi_poll_exchange(spi0, p_tx, p_rx, BUFF_LEN);
/* check data */
for (uint16_t i = 0; i < BUFF_LEN / 4; i++) {
if (((uint32_t *)p_rx)[i] != ((uint32_t *)p_tx)[i]) {
printf("data error, data[%d]:tx 0x%08lX, rx 0x%08lX\r\n", i, ((uint32_t *)p_tx)[i], ((uint32_t *)p_rx)[i]);
return -1;
}
}
printf("data check success\r\n");
return 0;
}
/* main */
int main(void)
{
board_init();
board_spi0_gpio_init();
struct bflb_spi_config_s spi_cfg = {
#if (SPI_CASE_SELECT == SPI_MASTER_CASE)
.freq = 1 * 1000 * 1000,
.role = SPI_ROLE_MASTER,
#else
.freq = 32 * 1000 * 1000,
.role = SPI_ROLE_SLAVE,
#endif
.mode = SPI_MODE3,
.data_width = SPI_DATA_WIDTH_8BIT,
.bit_order = SPI_BIT_MSB,
.byte_order = SPI_BYTE_LSB,
.tx_fifo_threshold = 0,
.rx_fifo_threshold = 0,
};
spi0 = bflb_device_get_by_name("spi0");
bflb_spi_init(spi0, &spi_cfg);
bflb_spi_feature_control(spi0, SPI_CMD_SET_CS_INTERVAL, 0);
printf("\r\n************** spi poll send 8-bit test **************\r\n");
if (bflb_spi_poll_test(SPI_DATA_WIDTH_8BIT) < 0) {
printf("poll send 8-bit test error!!!\r\n");
} else {
printf("poll send 8-bit test success!\r\n");
}
#if (SPI_CASE_SELECT == SPI_MASTER_CASE)
bflb_mtimer_delay_ms(1000); /* delay for slave device prepare ok */
#endif
printf("\r\n************** spi poll send 16-bit test **************\r\n");
if (bflb_spi_poll_test(SPI_DATA_WIDTH_16BIT) < 0) {
printf("poll send 16-bit test error!!!\r\n");
} else {
printf("poll send 16-bit test success!\r\n");
}
#if (SPI_CASE_SELECT == SPI_MASTER_CASE)
bflb_mtimer_delay_ms(1000); /* delay for slave device prepare ok */
#endif
printf("\r\n************** spi poll send 24-bit test **************\r\n");
if (bflb_spi_poll_test(SPI_DATA_WIDTH_24BIT) < 0) {
printf("poll send 24-bit test error!!!\r\n");
} else {
printf("poll send 24-bit test success!\r\n");
}
#if (SPI_CASE_SELECT == SPI_MASTER_CASE)
bflb_mtimer_delay_ms(1000); /* delay for slave device prepare ok */
#endif
printf("\r\n************** spi poll send 32-bit test **************\r\n");
if (bflb_spi_poll_test(SPI_DATA_WIDTH_32BIT) < 0) {
printf("poll send 32-bit test error!!!\r\n");
} else {
printf("poll send 32-bit test success!\r\n");
}
#if (SPI_CASE_SELECT == SPI_MASTER_CASE)
bflb_mtimer_delay_ms(1000); /* delay for slave device prepare ok */
#endif
printf("\r\n************** spi poll exchange 8-bit test **************\r\n");
if (bflb_spi_poll_exchange_test(SPI_DATA_WIDTH_8BIT) < 0) {
printf("poll exchange 8-bit test error!!!\r\n");
} else {
printf("poll exchange 8-bit test success!\r\n");
}
#if (SPI_CASE_SELECT == SPI_MASTER_CASE)
bflb_mtimer_delay_ms(1000); /* delay for slave device prepare ok */
#endif
printf("\r\n************** spi poll exchange 16-bit test **************\r\n");
if (bflb_spi_poll_exchange_test(SPI_DATA_WIDTH_16BIT) < 0) {
printf("poll exchange 16-bit test error!!!\r\n");
} else {
printf("poll exchange 16-bit test success!\r\n");
}
#if (SPI_CASE_SELECT == SPI_MASTER_CASE)
bflb_mtimer_delay_ms(1000); /* delay for slave device prepare ok */
#endif
printf("\r\n************** spi poll exchange 24-bit test **************\r\n");
if (bflb_spi_poll_exchange_test(SPI_DATA_WIDTH_24BIT) < 0) {
printf("poll exchange 24-bit test error!!!\r\n");
} else {
printf("poll exchange 24-bit test success!\r\n");
}
#if (SPI_CASE_SELECT == SPI_MASTER_CASE)
bflb_mtimer_delay_ms(1000); /* delay for slave device prepare ok */
#endif
printf("\r\n************** spi poll exchange 32-bit test **************\r\n");
if (bflb_spi_poll_exchange_test(SPI_DATA_WIDTH_32BIT) < 0) {
printf("poll exchange 32-bit test error!!!\r\n");
} else {
printf("poll exchange 32-bit test success!\r\n");
}
#if (SPI_CASE_SELECT == SPI_MASTER_CASE)
bflb_mtimer_delay_ms(1000); /* delay for slave device prepare ok */
#endif
printf("\r\n************** spi poll exchange only send 32-bit test **************\r\n");
bflb_spi_poll_exchange(spi0, tx_buff, NULL, BUFF_LEN);
printf("poll exchange 32-bit only send test end!\r\n");
#if (SPI_CASE_SELECT == SPI_MASTER_CASE)
bflb_mtimer_delay_ms(1000); /* delay for slave device prepare ok */
#endif
printf("\r\n************** spi poll exchange only receive 32-bit test **************\r\n");
bflb_spi_poll_exchange(spi0, NULL, rx_buff, BUFF_LEN);
printf("poll exchange 32-bit only receive test end!\r\n");
#if (SPI_CASE_SELECT == SPI_MASTER_CASE)
bflb_mtimer_delay_ms(1000); /* delay for slave device prepare ok */
#endif
printf("\r\n************** spi poll exchange spare time clock 32-bit test **************\r\n");
bflb_spi_poll_exchange(spi0, NULL, NULL, BUFF_LEN);
printf("poll exchange 32-bit spare time clock test end!\r\n");
printf("\r\nspi test end\r\n");
while (1) {
}
}FAQ
data check fail
自测时请确认 MOSI 与 MISO 已短接且与开发板共地；接从机时确认从机工作在相同 SPI 模式（例程为 MODE3）与频率。
想改数据宽度或模式
修改 SPI_CASE_SELECT 可以切换主机/从机角色；data_width、mode 在 spi_cfg 中修改，测试函数里的宽度由 bflb_spi_feature_control 动态切换。
例程没有输出
确认波特率 2000000 且已复位运行；SPI0 引脚接线不影响串口输出，若完全无打印先检查烧录与复位。
相关最佳实践
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