sim900A 的stm32代码

以下是一个简单的 sim900A 模块使用 STM32 的代码示例，可以作为参考：

#include "stm32f10x.h"
#include "stdio.h"
#include "string.h"

#define SIM900A_USART USART1

#define SIM900A_TX_PIN GPIO_Pin_9
#define SIM900A_RX_PIN GPIO_Pin_10
#define SIM900A_USART_GPIO GPIOA
#define SIM900A_USART_GPIO_CLK RCC_APB2Periph_GPIOA

#define SIM900A_PWR_PIN GPIO_Pin_11
#define SIM900A_RST_PIN GPIO_Pin_12
#define SIM900A_CTRL_GPIO GPIOB
#define SIM900A_CTRL_GPIO_CLK RCC_APB2Periph_GPIOB

#define SIM900A_BUFFER_SIZE 1024
#define SIM900A_TIMEOUT 1000

static uint8_t sim900a_buffer[SIM900A_BUFFER_SIZE];
static uint16_t sim900a_buffer_index = 0;
static uint8_t sim900a_rx_flag = 0;

void sim900a_init(void)
{
    USART_InitTypeDef USART_InitStructure;
    GPIO_InitTypeDef GPIO_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | SIM900A_USART_GPIO_CLK | SIM900A_CTRL_GPIO_CLK, ENABLE);

    GPIO_InitStructure.GPIO_Pin = SIM900A_TX_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(SIM900A_USART_GPIO, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = SIM900A_RX_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(SIM900A_USART_GPIO, &GPIO_InitStructure);

    USART_InitStructure.USART_BaudRate = 9600;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
    USART_Init(SIM900A_USART, &USART_InitStructure);

    USART_Cmd(SIM900A_USART, ENABLE);

    GPIO_InitStructure.GPIO_Pin = SIM900A_PWR_PIN | SIM900A_RST_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(SIM900A_CTRL_GPIO, &GPIO_InitStructure);

    GPIO_SetBits(SIM900A_CTRL_GPIO, SIM900A_PWR_PIN);
    GPIO_SetBits(SIM900A_CTRL_GPIO, SIM900A_RST_PIN);
}

void sim900a_send_byte(uint8_t data)
{
    USART_SendData(SIM900A_USART, data);
    while (USART_GetFlagStatus(SIM900A_USART, USART_FLAG_TXE) == RESET);
}

void sim900a_send_string(char *str)
{
    while (*str)
    {
        sim900a_send_byte(*str++);
    }
}

uint8_t sim900a_receive_byte(void)
{
    while (USART_GetFlagStatus(SIM900A_USART, USART_FLAG_RXNE) == RESET);
    return USART_ReceiveData(SIM900A_USART);
}

void sim900a_receive_data(void)
{
    uint8_t data;

    while (USART_GetFlagStatus(SIM900A_USART, USART_FLAG_RXNE) != RESET)
    {
        data = sim900a_receive_byte();
        if (sim900a_buffer_index < SIM900A_BUFFER_SIZE)
        {
            sim900a_buffer[sim900a_buffer_index++] = data;
            if (data == '\n' || data == '\r')
            {
                sim900a_rx_flag = 1;
            }
        }
        else
        {
            sim900a_buffer_index = 0;
        }
    }
}

uint8_t sim900a_send_command(const char *command, const char *response, uint16_t timeout)
{
    uint16_t i;

    sim900a_buffer_index = 0;
    sim900a_rx_flag = 0;

    sim900a_send_string((char *)command);
    sim900a_send_string("\r\n");

    for (i = 0; i < timeout; i++)
    {
        sim900a_receive_data();
        if (sim900a_rx_flag)
        {
            if (strstr((char *)sim900a_buffer, response))
            {
                return 1;
            }
            sim900a_rx_flag = 0;
            sim900a_buffer_index = 0;
        }
        delay_ms(1);
    }

    return 0;
}

int main(void)
{
    sim900a_init();

    while (1)
    {
        if (sim900a_send_command("AT", "OK", SIM900A_TIMEOUT))
        {
            printf("SIM900A is ready.\n");
        }
        else
        {
            printf("SIM900A is not responding.\n");
        }

        delay_ms(1000);
    }
}

需要注意的是，以上代码仅作为示例，实际使用时需要根据具体的硬件连接和需求进行修改。同时，使用 sim900A 模块需要注意其电源、复位等控制引脚的使用方法。