點亮一個燈管與在屏幕上顯示一個圖案是同樣的原理，衹需要發送一條指令。

這種編程，其實再簡單不過。關鍵是硬件的排綫，排好了就有一張端口地址表，要哪條管亮，就向哪個地址發0/1訊號（實際上這種訊號是可編程的，不必所有製作都一樣），與在屏幕上點亮一個點是完全一樣的原理。我寫的這個樣板，已經把畫一組七段管的函數封裝起來，操縱者衹要發數字即可（這就是系統調用的道理，文本模式的用BOIS中斷請求向屏幕輸出字符就是這樣）。作爲使用者，是不需要知道硬件細節的。完成任務，就靠那張（字符圖案）對應表，不同硬件，換一份就是了。

這是主程序：

#include <Windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <conio.h>
#include "tools.h"
#include "LED.h"

HANDLE Console_Output = GetStdHandle(STD_OUTPUT_HANDLE);

int main(void)
{
    SetConsoleTitleA("七段管演示");

    const char* tips = "Press any key...";
    const char* message = "請輸入需要顯示的數字(直接按<Enter>鍵結束程序):";
    COORD pos;

    char buffer[81];
    do
    {
        ClearScreen();
        pos.X = 0;
        pos.Y = 0;
        Say(message, pos);
        GotoXY((SHORT)strlen(message) + 1, pos.Y);
        if (gets_s(buffer, _countof(buffer)) && (buffer[0] != '\0'))
        {
            int number = atoi(buffer);
            sprintf_s(buffer, "%u", number);
            SHORT length = (SHORT)strlen(buffer);
            for (SHORT index = 0; index < length; ++index)
            {
                LED_On(buffer[index] - '0', 1 + index * (LED_Width + 1), 5);    // 向指定組輸出一位數字
            }
            pos.X = 0;
            pos.Y = 24;
            Say(tips, pos);
            GotoXY((SHORT)strlen(tips), pos.Y);
            _getch();
        }
    } while (buffer[0] != '\0');

    return EXIT_SUCCESS;
}

重點是這張表：

static const WORD Light[10][4]
{ 
    // 0
    { 
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_GRID_LVERTICAL, 
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_GRID_RVERTICAL, 
        COMMON_LVB_UNDERSCORE + COMMON_LVB_GRID_LVERTICAL, 
        COMMON_LVB_UNDERSCORE + COMMON_LVB_GRID_RVERTICAL 
    },
    // 1
    { 
        0, 
        COMMON_LVB_GRID_RVERTICAL,
        0, 
        COMMON_LVB_GRID_RVERTICAL 
    },
    // 2
    { 
        COMMON_LVB_GRID_HORIZONTAL, 
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_GRID_RVERTICAL, 
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_UNDERSCORE + COMMON_LVB_GRID_LVERTICAL, 
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_UNDERSCORE 
    },
    // 3
    {
        COMMON_LVB_GRID_HORIZONTAL,
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_GRID_RVERTICAL,
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_UNDERSCORE,
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_UNDERSCORE + COMMON_LVB_GRID_RVERTICAL
    },
    // 4
    {
        COMMON_LVB_GRID_LVERTICAL,
        COMMON_LVB_GRID_RVERTICAL,
        COMMON_LVB_GRID_HORIZONTAL,
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_GRID_RVERTICAL
    },
    // 5
    {
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_GRID_LVERTICAL,
        COMMON_LVB_GRID_HORIZONTAL,
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_UNDERSCORE,
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_UNDERSCORE + COMMON_LVB_GRID_RVERTICAL
    },
    // 6
    {
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_GRID_LVERTICAL,
        COMMON_LVB_GRID_HORIZONTAL,
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_UNDERSCORE + COMMON_LVB_GRID_LVERTICAL,
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_UNDERSCORE + COMMON_LVB_GRID_RVERTICAL
    },
    // 7
    {
        COMMON_LVB_GRID_HORIZONTAL,
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_GRID_RVERTICAL,
        0,
        COMMON_LVB_GRID_RVERTICAL
    },
    // 8
    {
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_GRID_LVERTICAL,
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_GRID_RVERTICAL,
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_UNDERSCORE + COMMON_LVB_GRID_LVERTICAL,
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_UNDERSCORE + COMMON_LVB_GRID_RVERTICAL
    },
    // 9
    {
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_GRID_LVERTICAL,
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_GRID_RVERTICAL,
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_UNDERSCORE,
        COMMON_LVB_GRID_HORIZONTAL + COMMON_LVB_UNDERSCORE + COMMON_LVB_GRID_RVERTICAL
    }
};

在控制機那裏，這張表是10個char的數組char[10]，每個char衹使用7bit，按照前面a-g的順序（由排綫決定）依次填0/1，則每個char就是一個0-9數字的點陣圖，要顯示哪個數字，就提取對應的char，依次點亮對應燈管就是了。每組（7段）都有一個起始地址，相當於我16樓代碼LED_On()函數的第二個參數。封裝的LED_On()函數，接口協議衹是接收需要顯示的數字和組地址，該函數的動作，就是提取數字對應的char，按順序把用到的7bit以0/1模式發出即可。其實，單片機在板上，根本用不着靠bit壓縮空間，所有10字符點陣，用char:0/1存儲，也不過是70字節，代碼上比用位操作直接得多。比特壓縮的情形，以前是用在通過串口傳遞點陣圖案上的，在本地機上，不必這麽繞圈，寫位操作的代碼占用内存，也不止70字節，畢竟你最終還是把0/1以1Byte的代價發出去。換句話説，這張表可以用char[10][7]的，總共也就70Byte的消耗，比寫晦澀難懂的位操作代碼清晰得多。

[此贴子已经被作者于2015-10-21 19:28编辑过]

单片机里通常是位操作，假设如楼主7楼所示a到g对应一个字节的0到7位，则显示8的数据为0x7F,显示0的数据为0x3F，显示1为0x06.