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stm32_spislave.c
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stm32_spislave.c
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/*
* stm32_spislave.c
*
* Created on: 2014年10月20日
* Author: zhouyu
*/
#include <stdint.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <spidev.h>
#include <stm32_spislave.h>
static int spi_fd; //spi设备文件句柄
static int spibus_num = 1; //SPI设备总线号
static int spichipselect_num = 0; //SPI片选号，a SPI device with chipselect C on bus B, you should see /dev/spidevB.C
static uint32_t mode = 0; //（POL，PHA），MODE0=（0,0）MODE1=（0,1）MODE2=（1,0）MODE3=（1,1）,POL=0表示时钟空闲为低电平，1为高电平；PHA=0表示采样发生在时钟的第一个跳变边沿，1表示第二个跳变边沿
static uint8_t bits = 16; //每次通信的比特长度，这个长度依从设备而不同
static uint32_t speed = 9000000; //SCLK的频率，单位Hz
static uint16_t delay = 0; //当有多个从设备时，本次通信传输完成后在取消选中本片选线之前，延长多长时间（这个时间过后接着取消本片选线，选中其他片选线开始下一次传输）
static struct spi_ioc_transfer tr; //用于进行全双工通信配置，具体参考spidev.h
void stm32_Init()
{
int ret;
char temp_str[50] = {0};
/* 获取设备文件指针 */
sprintf(temp_str, "/dev/spidev%d.%d",spibus_num, spichipselect_num);//将整形参数转换成字符串
spi_fd = open(temp_str, O_RDWR);
if (spi_fd < 0)
printf("can't open device");
/* 通信格式参数配置,依从设备而不同 */
/*
* spi mode
*/
ret = ioctl(spi_fd, SPI_IOC_WR_MODE, &mode);
if (ret == -1)
printf("can't set spi mode");
ret = ioctl(spi_fd, SPI_IOC_RD_MODE, &mode);
if (ret == -1)
printf("can't get spi mode");
/*
* bits per word
*/
ret = ioctl(spi_fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
if (ret == -1)
printf("can't set bits per word");
ret = ioctl(spi_fd, SPI_IOC_RD_BITS_PER_WORD, &bits);
if (ret == -1)
printf("can't get bits per word");
/*
* max speed hz
*/
ret = ioctl(spi_fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
if (ret == -1)
printf("can't set max speed hz");
ret = ioctl(spi_fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed);
if (ret == -1)
printf("can't get max speed hz");
/* spi_ioc_transfer相关配置 */
tr.delay_usecs = delay;
tr.speed_hz = speed;
tr.bits_per_word = bits;
if (mode & SPI_TX_QUAD)
tr.tx_nbits = 4;
else if (mode & SPI_TX_DUAL)
tr.tx_nbits = 2;
if (mode & SPI_RX_QUAD)
tr.rx_nbits = 4;
else if (mode & SPI_RX_DUAL)
tr.rx_nbits = 2;
if (!(mode & SPI_LOOP))
{
if (mode & (SPI_TX_QUAD | SPI_TX_DUAL))
tr.rx_buf = 0;
else if (mode & (SPI_RX_QUAD | SPI_RX_DUAL))
tr.tx_buf = 0;
}
}
void stm32_Transfer(uint16_t *TxBuf, uint16_t *RxBuf, int len_in_bytes)
{
/* 为每一次SPI Transfer进行配置*/
tr.tx_buf = (unsigned long)TxBuf;
tr.rx_buf = (unsigned long)RxBuf;
tr.len = len_in_bytes;
/* 双向传输数据 */
SPI_Transfer(spi_fd, 1, &tr);
}
void stm32_Close()
{
/* 关闭SPI设备的文件指针 */
close(spi_fd);
}