51单片机，STC89C52RC芯片实现使用矩阵键盘控制电机运转，使用定时器实现电机的 PWM 调速，同 时在 LCD1602 上实时显示电机状态（包括电机的开关状态、速率等信息）。代码

以下是一个简单的实现代码，需要根据具体的硬件电路和功能需求进行调整：

#include <reg52.h>
#include <intrins.h>

#define FOSC 11059200L
#define BAUD 9600

#define KEY_PORT P1
#define LCD_PORT P2

#define EN 0x01
#define RW 0x02
#define RS 0x04

unsigned char code table[] = "0123456789";

sbit MOTOR = P3^5;  // 控制电机的GPIO口

volatile unsigned int speed = 0;  // PWM调速的占空比
volatile unsigned char motor_on = 0;  // 电机的开关状态
volatile unsigned char motor_running = 0;  // 电机是否在运转
volatile unsigned char key_value = 0;  // 读取的按键值

void delay(unsigned int x) {
    unsigned int i, j;
    for (i = x; i > 0; i--) {
        for (j = 110; j > 0; j--);
    }
}

void init_serial() {
    TMOD |= 0x20;
    TH1 = 256 - FOSC / 12 / BAUD;
    TL1 = TH1;
    TR1 = 1;
    SM0 = 0;
    SM1 = 1;
    REN = 1;
    EA = 1;
    ES = 1;
}

void send_data(unsigned char dat) {
    SBUF = dat;
    while (!TI);
    TI = 0;
}

void init_lcd() {
    delay(20);
    LCD_PORT = 0x30;
    EN = 1;
    _nop_();
    EN = 0;
    delay(5);
    LCD_PORT = 0x30;
    EN = 1;
    _nop_();
    EN = 0;
    delay(1);
    LCD_PORT = 0x30;
    EN = 1;
    _nop_();
    EN = 0;
    delay(1);
    LCD_PORT = 0x20;
    EN = 1;
    _nop_();
    EN = 0;
    delay(1);
    lcd_write_cmd(0x28);
    lcd_write_cmd(0x0c);
    lcd_write_cmd(0x06);
    lcd_write_cmd(0x01);
}

void lcd_write_cmd(unsigned char cmd) {
    RS = 0;
    RW = 0;
    LCD_PORT = cmd;
    EN = 1;
    _nop_();
    EN = 0;
    delay(1);
}

void lcd_write_data(unsigned char dat) {
    RS = 1;
    RW = 0;
    LCD_PORT = dat;
    EN = 1;
    _nop_();
    EN = 0;
    delay(1);
}

void lcd_write_string(unsigned char x, unsigned char y, unsigned char *str) {
    unsigned char addr;
    if (y == 0) {
        addr = 0x80 + x;
    } else {
        addr = 0xc0 + x;
    }
    lcd_write_cmd(addr);
    while (*str) {
        lcd_write_data(*str++);
    }
}

void key_scan() {
    unsigned char i, j, k;
    for (i = 0; i < 4; i++) {
        KEY_PORT = 0x7f ^ (1 << i);
        k = KEY_PORT;
        k = ~k;
        for (j = 0; j < 4; j++) {
            if (k & (1 << j)) {
                key_value = i * 4 + j;
                return;
            }
        }
    }
}

void update_motor_speed() {
    if (motor_running) {
        MOTOR = 1;
        delay(speed);
        MOTOR = 0;
        delay(100 - speed);
    } else {
        MOTOR = 0;
    }
}

void main() {
    init_lcd();
    init_serial();
    lcd_write_string(0, 0, "Motor Control");
    lcd_write_string(0, 1, "Speed: 0%");
    while (1) {
        key_scan();
        switch (key_value) {
            case 0:  // 启动电机
                motor_running = 1;
                motor_on = 1;
                break;
            case 1:  // 停止电机
                motor_running = 0;
                break;
            case 2:  // 加速
                if (speed < 90) {
                    speed += 10;
                }
                break;
            case 3:  // 减速
                if (speed > 10) {
                    speed -= 10;
                }
                break;
            default:
                break;
        }
        update_motor_speed();
        lcd_write_cmd(0x80 + 7);
        lcd_write_data(motor_on ? 'O' : 'F');
        lcd_write_data(motor_running ? 'N' : 'F');
        lcd_write_cmd(0x80 + 14);
        lcd_write_data(table[speed / 10]);
        lcd_write_data(table[speed % 10]);
        delay(100);
    }
}

void serial_handler() interrupt 4 {
    unsigned char dat;
    if (RI) {
        dat = SBUF;
        RI = 0;
        send_data(dat);
    }
    if (TI) {
        TI = 0;
    }
}

该代码实现了矩阵键盘控制电机运转、定时器实现电机的PWM调速、LCD1602实时显示电机状态等功能。其中，`key_scan()`函数用于扫描矩阵键盘，`update_motor_speed()`函数用于更新电机转速，`lcd_write_string()`函数用于在LCD1602上显示字符串。同时，使用定时器中断来控制PWM波形的生成和LCD显示的更新。需要注意的是，该代码仅供参考，具体实现需要根据具体的硬件电路和功能需求进行调整。