STC 8A8K64D4单片机 uart4接收 DMX512协议数据程序

以下是STC 8A8K64D4单片机通过uart4接收DMX512协议数据的示例程序：

#include <reg52.h>

#define DMX_FRAME_SIZE 513

unsigned char dmx_frame[DMX_FRAME_SIZE];

void uart4_init() {
    S4CON = 0x50;       // 8-bit UART, enable receiver
    T4CON = 0x00;       // Timer4 in mode 0, no timer interrupt
    P4SW = 0x80;        // Enable UART4 pins (P4.6 = TX4, P4.7 = RX4)
    PCON |= 0x80;       // SMOD = 1 for double baud rate
    TH4 = 0xFF;         // Set initial timer value (auto-reload)
    TL4 = 0xFF;
    RCAP4L = 0xFF;      // Set reload timer value
    RCAP4H = 0xFF;
    TR4 = 1;            // Start timer4
}

void uart4_isr() interrupt 16 {
    static unsigned char dmx_index = 0;
    static unsigned char dmx_state = 0;
    
    if (S4CON & 0x01) {     // Check if RX4 interrupt flag is set
        S4CON &= ~0x01;     // Clear RX4 interrupt flag
        
        if (dmx_state == 0) {
            if (S4BUF == 0x00) {    // Start code
                dmx_index = 0;
                dmx_state = 1;
            }
        } else {
            dmx_frame[dmx_index++] = S4BUF;
            
            if (dmx_index == DMX_FRAME_SIZE) {   // End of frame
                dmx_index = 0;
                dmx_state = 0;
            }
        }
    }
}

void main() {
    EA = 1;         // Enable global interrupts
    ES4 = 1;        // Enable UART4 interrupts
    
    uart4_init();
    
    while (1) {
        // Do something with the DMX512 data...
    }
}

这个程序初始化了UART4，然后在UART4接收到数据时，将数据存储在一个缓冲区中。当缓冲区中收到了完整的DMX512帧时，程序可以对这个帧进行处理。注意，DMX512协议使用的是异步串口通信，波特率为250 kbps。