请帮我设计一个stm32f103程序使其可以接收来自python串口通信的字符，并根据接受的字符控制两个级联MAX7219led点阵显示笑脸和爱心两种不同的表情

好的，首先需要在stm32f103上配置串口接收功能和使用MAX7219控制led点阵的功能。以下是一个简单的示例程序供参考：

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

#define MAX7219_CS_PIN GPIO_Pin_4
#define MAX7219_CS_PORT GPIOA
#define USART_RX_PIN GPIO_Pin_3
#define USART_RX_PORT GPIOA
#define USART_TX_PIN GPIO_Pin_2
#define USART_TX_PORT GPIOA
#define BAUD_RATE 9600

void USART1_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA, ENABLE);

    GPIO_InitStructure.GPIO_Pin = USART_RX_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(USART_RX_PORT, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = USART_TX_PIN;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_Init(USART_TX_PORT, &GPIO_InitStructure);

    USART_InitStructure.USART_BaudRate = BAUD_RATE;
    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(USART1, &USART_InitStructure);

    USART_Cmd(USART1, ENABLE);
}

void MAX7219_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    SPI_InitTypeDef SPI_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1 | RCC_APB2Periph_GPIOA, ENABLE);

    GPIO_InitStructure.GPIO_Pin = MAX7219_CS_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(MAX7219_CS_PORT, &GPIO_InitStructure);
    GPIO_SetBits(MAX7219_CS_PORT, MAX7219_CS_PIN);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_7;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    SPI_InitStructure.SPI_Direction = SPI_Direction_1Line_Tx;
    SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
    SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
    SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
    SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
    SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
    SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256;
    SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
    SPI_Init(SPI1, &SPI_InitStructure);

    SPI_Cmd(SPI1, ENABLE);

    MAX7219_Write(0x09, 0x00);
    MAX7219_Write(0x0a, 0x03);
    MAX7219_Write(0x0b, 0x07);
    MAX7219_Write(0x0c, 0x01);
    MAX7219_Write(0x0f, 0x00);
}

void MAX7219_Write(unsigned char reg, unsigned char data)
{
    GPIO_ResetBits(MAX7219_CS_PORT, MAX7219_CS_PIN);
    SPI_I2S_SendData(SPI1, reg);
    while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
    SPI_I2S_SendData(SPI1, data);
    while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
    GPIO_SetBits(MAX7219_CS_PORT, MAX7219_CS_PIN);
}

void MAX7219_Display(unsigned char row, unsigned char col, unsigned char data)
{
    if (row > 7 || col > 7)
        return;

    unsigned char reg = 0x01 + row;
    unsigned char mask = 0x80 >> col;
    unsigned char val = data & mask ? 0x01 : 0x00;

    MAX7219_Write(reg, (MAX7219_Read(reg) & ~mask) | (val << col));
}

unsigned char MAX7219_Read(unsigned char reg)
{
    unsigned char data = 0;

    GPIO_ResetBits(MAX7219_CS_PORT, MAX7219_CS_PIN);
    SPI_I2S_SendData(SPI1, reg | 0x80);
    while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
    SPI_I2S_SendData(SPI1, 0x00);
    while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
    data = SPI_I2S_ReceiveData(SPI1);
    GPIO_SetBits(MAX7219_CS_PORT, MAX7219_CS_PIN);

    return data;
}

void USART1_IRQHandler(void)
{
    if (USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)
    {
        unsigned char c = USART_ReceiveData(USART1);

        switch (c)
        {
            case '1':
                // 显示笑脸
                MAX7219_Display(0, 1, 0x18);
                MAX7219_Display(0, 2, 0x24);
                MAX7219_Display(0, 3, 0x42);
                MAX7219_Display(0, 4, 0x42);
                MAX7219_Display(0, 5, 0x42);
                MAX7219_Display(0, 6, 0x42);
                MAX7219_Display(0, 7, 0x3c);
                break;
            case '2':
                // 显示爱心
                MAX7219_Display(0, 0, 0x18);
                MAX7219_Display(0, 1, 0x3c);
                MAX7219_Display(0, 2, 0x7e);
                MAX7219_Display(0, 3, 0xff);
                MAX7219_Display(0, 4, 0xff);
                MAX7219_Display(0, 5, 0x7e);
                MAX7219_Display(0, 6, 0x3c);
                MAX7219_Display(0, 7, 0x18);
                break;
        }
    }
}

int main(void)
{
    USART1_Init();
    MAX7219_Init();

    while (1)
    {
    }
}

在上面的代码中，我们使用了stm32f103的串口1和SPI1模块。串口1用于接收来自python程序发送的字符，SPI1用于控制两个级联的MAX7219芯片，从而控制两个led点阵。

在main函数中，我们初始化了串口1和MAX7219芯片，然后进入一个无限循环等待串口1接收到字符。当接收到字符后，我们根据字符的值选择显示笑脸或爱心。具体的显示方式在USART1_IRQHandler中实现，这是一个由stm32f103内部硬件自动调用的中断服务程序。

需要注意的是，MAX7219_Display函数用于控制具体的led点阵显示方式，其中第一个参数row表示行数，第二个参数col表示列数，第三个参数data表示具体的显示数据。使用该函数前需要先初始化MAX7219芯片。

此外，还需要在python程序中使用pyserial模块打开串口并发送字符。以下是一个简单的python程序供参考：

import serial

ser = serial.Serial("/dev/ttyUSB0", 9600, timeout=1)

while True:
    cmd = input("请输入指令(1.笑脸 2.爱心): ")
    if cmd == "1" or cmd == "2":
        ser.write(cmd.encode())
    else:
        print("无效指令")

在该python程序中，我们通过pyserial模块打开串口/dev/ttyUSB0，并设置波特率为9600。然后进入一个循环等待用户输入指令。如果用户输入了有效指令，则将指令发送到stm32f103的串口1中。需要注意的是，由于串口数据是以字节形式传输的，因此需要将指令先编码为字节再发送到串口中。

综上所述，该程序可以实现通过串口控制两个级联MAX7219led点阵显示笑脸和爱心两种不同的表情。