STM32L010のソフトウェアシリアルで文字を受信する STM32 RX 9600bps


x Mbedのリビジョンは、125

目的
表示器等用のソフトウェアシリアルを作ってみた。

忙しい人よう
https://os.mbed.com/users/caa45040/code/serial_rx_test_010/

```c++

#include "mbed.h"

//10の割り算 0から1028までは、正しい。主に0から999
#define DVI10(n) ((n*205)>>11)

//Serial pc(USBTX, USBRX); // tx, rx
//Serial pc(SERIAL_TX, SERIAL_RX); //767
//Serial pc(PA_2, PA_3); //010
//Serial pc(PA_9, PA_10); //010

#define UART_DELAY 96 //  1/9600

DigitalOut TX(PA_2);
DigitalIn  RX(PA_3);
//DigitalOut TX(PA_9);
//DigitalIn  RX(PA_10);

char ch_hex_a_b[5];
char *ch_hex_a(int l_num)
{
    int a,b,c;

    int q=0;
if(l_num  < 0) { l_num = 0 - l_num; q = 1;} 

    b=DVI10(l_num);
    c=l_num-(b*10);
    l_num=b;
    a=DVI10(l_num);
    b=l_num-(a*10);

    ch_hex_a_b[0] = '0' + a;
    ch_hex_a_b[1] = '0' + b;
    ch_hex_a_b[2] = '0' + c;
    ch_hex_a_b[3] = 0;

if( q == 1 ) {ch_hex_a_b[0]='-';}

    return(ch_hex_a_b);
} //ch_hex_a


//仮想シリアルへの一文字出力 9600bps
int pc_putc(char ch) {
        
    TX=1;
    TX=0;//START
    wait_us(UART_DELAY);

    for(int ii=0;ii<8;ii++){
        TX=(ch>>ii)&1;
        wait_us(UART_DELAY);
    }; //for

    TX=1;//Stop
    wait_us(UART_DELAY);
             
    return(0);
    
} //pc_putc

//文字列の表示
int pc_printf(char *str1) {

    int ii = 0; //ループカウンター
    while(str1[ii]!=0){
            
        //一文字出力
        pc_putc(str1[ii]);ii++;
                        
    } //while

    //戻り値
    return(0);
}

//タイマーの定義
Timer t;

int a,b,c,d,e,f,g,h;
int bs;
int zt,at,bt,ct,dt,et,ft,gt,ht,it;
char *ret1="\r\n";


int pc_getc()
{

    //待ちループ
    while( RX == 1 ) {} 

//llllllllllllllllllllllllllllllllllllllll

    zt = t.read_us();

    wait_us(156-7-12);

    a=RX;
    at = t.read_us();

    wait_us(104-7-11);

    b=RX;
    bt = t.read_us();

    wait_us(104-7-11);

    c=RX;
    ct = t.read_us();

    wait_us(104-7-11);

    d=RX;
    dt = t.read_us();
    
    wait_us(104-7-10);
    
//hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh   
    
    e=RX;
    et = t.read_us();

    wait_us(104-7-11);

    f=RX;
    ft = t.read_us();

    wait_us(104-7-12);

    g=RX;
    gt = t.read_us();

    wait_us(104-7-11);

    h=RX;
    ht = t.read_us();

    wait_us(156-7-11);

    it = t.read_us();
    
//pc_printf(ret1);
//pc_printf("0    zt=");
//pc_printf(  ch_hex_a(zt)  );
//pc_printf(ret1);

//pc_printf("156  at=");
//pc_printf(  ch_hex_a( 156  - (at-zt) )  );
//pc_printf(ret1);

//pc_printf("260  bt=");
//pc_printf(  ch_hex_a( 260  - (bt-zt) )  );
//pc_printf(ret1);

//pc_printf("364  ct=");
//pc_printf(  ch_hex_a( 364  - (ct-zt) )  );
//pc_printf(ret1);

//pc_printf("468  dt=");
//pc_printf(  ch_hex_a( 468  - (dt-zt) )  );
//pc_printf(ret1);

//pc_printf("572  et=");
//pc_printf(  ch_hex_a( 572  - (et-zt) )  );
//pc_printf(ret1);

//pc_printf("677  ft=");
//pc_printf(  ch_hex_a( 677  - (ft-zt) )  );
//pc_printf(ret1);

//pc_printf("781  gt=");
//pc_printf(  ch_hex_a( 781  - (gt-zt) )  );
//pc_printf(ret1);

//pc_printf("885  ht=");
//pc_printf(  ch_hex_a( 885  - (ht-zt) )  );
//pc_printf(ret1);

//pc_printf("1041 it=");
//pc_printf(  ch_hex_a( 1041 - (it-zt) )  );
//pc_printf(ret1);

    //h=0; g=1; f=0; e=0; d=0; c=0; b=0; a=1;

    bs=h*128+g*64+f*32+e*16+d*8+c*4+b*2+a;

    //char str2[2]={ bs ,0};
    //pc_printf("     ch=[");
    //pc_printf(  str2  );
    //pc_printf(ret1);

    return(bs);
}//pc_getc

int main()
{
    RX.mode( PullUp );   //  内蔵プルアップを使う
    
    //タイマーの開始
    t.start();
    //pc.printf("Hello World!\r\n");
    //t.stop();

    char ch;
    
    while(1) {

        t.reset();

        ch = pc_getc();
        
        char str2[2]={ ch ,0};
        pc_printf("-----ch=[");
        pc_printf(  str2  );
        pc_printf(ret1);


        wait(1.0);
    }//while
}//main

//容量削減
void error(const char* format, ...){}



```

![timer_test_010_2.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/840352/0b5efe9d-8279-64d4-02fd-a6634bbdae3f.jpeg)

![serial_test_010_2_3.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/840352/c38256b9-4f20-bb9c-2f3c-756397d4b20d.jpeg)

![serial_test_010_2_4.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/840352/7c3108ab-db80-5f36-0eca-7b43b16b9bbb.jpeg)

![serial_test_010_2_5.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/840352/6d992a2a-2ed9-1527-c883-4552a2d4d5d2.jpeg)

![serial_test_p1_3.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/840352/e8e4f00a-58ac-eaed-5944-f2850babdde1.jpeg)