利用USART1串口输入大量字符然后用DMA方式将这些字符信息传输到主存。统计这些字符中字母字符的个数并由UASRT1串口显示统计结果请写出完整具体的代码

以下是基于STM32F103C8T6开发板的代码：

#include "stm32f10x.h"

// 定义缓冲区大小
#define BUFFER_SIZE 100

uint8_t dataBuffer[BUFFER_SIZE];  // 数据缓冲区
uint8_t count = 0;  // 字母字符计数器

void USART1_IRQHandler(void)
{
    // 判断是否接收到数据
    if (USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)
    {
        dataBuffer[count] = USART_ReceiveData(USART1);  // 读取数据
        count++;  // 计数器自增

        // 判断是否超出缓冲区大小
        if (count >= BUFFER_SIZE)
        {
            count = 0;  // 重置计数器
        }
    }
}

int main(void)
{
    // 使能USART1和DMA1时钟
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);

    // 配置USART1的GPIO
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;  // TX
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;  // RX
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    // 配置USART1
    USART_InitTypeDef USART_InitStructure;
    USART_InitStructure.USART_BaudRate = 115200;
    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_Tx | USART_Mode_Rx;
    USART_Init(USART1, &USART_InitStructure);

    // 配置USART1中断
    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    // 使能USART1接收中断
    USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);

    // 启动USART1
    USART_Cmd(USART1, ENABLE);

    // 配置DMA1
    DMA_InitTypeDef DMA_InitStructure;
    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&USART1->DR;
    DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)dataBuffer;
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
    DMA_InitStructure.DMA_BufferSize = BUFFER_SIZE;
    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
    DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
    DMA_InitStructure.DMA_Priority = DMA_Priority_High;
    DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
    DMA_Init(DMA1_Channel5, &DMA_InitStructure);

    // 启动DMA1
    DMA_Cmd(DMA1_Channel5, ENABLE);

    while (1)
    {
        // 统计字母字符的个数
        uint8_t i;
        for (i = 0; i < BUFFER_SIZE; i++)
        {
            if ((dataBuffer[i] >= 'a' && dataBuffer[i] <= 'z') || (dataBuffer[i] >= 'A' && dataBuffer[i] <= 'Z'))
            {
                count++;  // 计数器自增
            }
        }

        // 将统计结果发送到USART1
        char result[20];
        sprintf(result, "Letter count: %d\r\n", count);
        uint8_t len = strlen(result);
        uint8_t j;
        for (j = 0; j < len; j++)
        {
            USART_SendData(USART1, result[j]);
            while (USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
        }

        count = 0;  // 重置计数器
    }
}