80C51单片机外扩32位RAM自检

在8051单片机片外扩62256芯片（32K Bytes RAM），将其映射到8051芯片的外部数据空间地址并编程实现对62256芯片RAM自检，在P1.0口驱动绿色LED，P1.1口驱动红色LED，当自检通过时绿色LED每秒闪烁1次，红色LED不亮；当自检不通过时红色LED每秒闪烁2次，绿色LED不亮。

#include <reg51.h>

#define EXTERNAL_RAM_SIZE 32768 // 32KB
#define TEST_PATTERN 0xAA // Test pattern for write and read operations

unsigned char external_ram[EXTERNAL_RAM_SIZE];

void delay() {
    // Delay function (adjust the value depending on the clock frequency)
    for (int i = 0; i < 50000; i++);
}

void selfTestPassed() {
    P1 &= ~(1 << 1); // Turn off the red LED
    while (1) {
        P1 ^= (1 << 0); // Toggle the green LED
        delay();
    }
}

void selfTestFailed() {
    P1 &= ~(1 << 0); // Turn off the green LED
    while (1) {
        P1 ^= (1 << 1); // Toggle the red LED
        delay();
        delay();
    }
}

void main() {
    // Configure P1.0 and P1.1 as output pins for driving LEDs
    P1 = P1 & 0xFC;

    // Write test pattern to external RAM
    for (int i = 0; i < EXTERNAL_RAM_SIZE; i++) {
        external_ram[i] = TEST_PATTERN;
    }

    // Read and verify test pattern from external RAM
    for (int i = 0; i < EXTERNAL_RAM_SIZE; i++) {
        if (external_ram[i] != TEST_PATTERN) {
            selfTestFailed(); // Perform actions for self-test failure
        }
    }

    selfTestPassed(); // Perform actions for self-test success
    while(1){}
}