stm32samples/F1:F103/CDC_ACM/main.c

/*
 * main.c
 *
 * Copyright 2017 Edward V. Emelianoff <eddy@sao.ru, edward.emelianoff@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 */

#include "hardware.h"
#include "proto.h"
#include "usb.h"
#include "usb_lib.h"

volatile uint32_t Tms = 0;

/* Called when systick fires */
void sys_tick_handler(void){
    ++Tms;
}

void iwdg_setup(){
    uint32_t tmout = 16000000;
    /* Enable the peripheral clock RTC */
    /* (1) Enable the LSI (40kHz) */
    /* (2) Wait while it is not ready */
    RCC->CSR |= RCC_CSR_LSION; /* (1) */
    while((RCC->CSR & RCC_CSR_LSIRDY) != RCC_CSR_LSIRDY){if(--tmout == 0) break;} /* (2) */
    /* Configure IWDG */
    /* (1) Activate IWDG (not needed if done in option bytes) */
    /* (2) Enable write access to IWDG registers */
    /* (3) Set prescaler by 64 (1.6ms for each tick) */
    /* (4) Set reload value to have a rollover each 2s */
    /* (5) Check if flags are reset */
    /* (6) Refresh counter */
    IWDG->KR = IWDG_START; /* (1) */
    IWDG->KR = IWDG_WRITE_ACCESS; /* (2) */
    IWDG->PR = IWDG_PR_PR_1; /* (3) */
    IWDG->RLR = 1250; /* (4) */
    tmout = 16000000;
    while(IWDG->SR){if(--tmout == 0) break;} /* (5) */
    IWDG->KR = IWDG_REFRESH; /* (6) */
}

#define USBBUF 63
// usb getline
static char *get_USB(){
    static char tmpbuf[USBBUF+1], *curptr = tmpbuf;
    static int rest = USBBUF;
    uint8_t x = USB_receive((uint8_t*)curptr);
    if(!x) return NULL;
    curptr[x] = 0;
    if(x == 1 && *curptr == 0x7f){ // backspace
        if(curptr > tmpbuf){
            --curptr;
            USND("\b \b");
        }
        return NULL;
    }
    USB_sendstr(curptr); // echo
    if(curptr[x-1] == '\n'){ // || curptr[x-1] == '\r'){
        curptr = tmpbuf;
        rest = USBBUF;
        // omit empty lines
        if(tmpbuf[0] == '\n') return NULL;
        // and wrong empty lines
        if(tmpbuf[0] == '\r' && tmpbuf[1] == '\n') return NULL;
        return tmpbuf;
    }
    curptr += x; rest -= x;
    if(rest <= 0){ // buffer overflow
        curptr = tmpbuf;
        rest = USBBUF;
    }
    return NULL;
}

/* - these functions need for true USB-TTY
static uint32_t newrate = 0;
// redefine weak handlers
void linecoding_handler(usb_LineCoding *lcd){
    newrate = lcd->dwDTERate;
}
static uint16_t cl = 0xffff;
void clstate_handler(uint16_t val){
    cl = val;
}
static int8_t br = 0;
void break_handler(){
    br = 1;
}*/

int main(void){
    uint32_t lastT = 0;
    sysreset();
    StartHSE();
    SysTick_Config(72000);
    hw_setup();

    USBPU_OFF();
/*    if(RCC->CSR & RCC_CSR_IWDGRSTF){ // watchdog reset occured
        SEND("WDGRESET=1"); newline();
    }
    if(RCC->CSR & RCC_CSR_SFTRSTF){ // software reset occured
        SEND("SOFTRESET=1"); newline();
    }*/
    RCC->CSR |= RCC_CSR_RMVF; // remove reset flags

    USB_setup();
    iwdg_setup();
    USBPU_ON();

    while (1){
        IWDG->KR = IWDG_REFRESH; // refresh watchdog
        if(Tms - lastT > 499){
            LED_blink(LED0);
            lastT = Tms;
        }
        usb_proc();
        char *txt = get_USB();
        if(txt){
            IWDG->KR = IWDG_REFRESH;
            cmd_parser(txt);
        }
        /*
        int n = 0;
        if(newrate){SEND("new speed: "); printu(newrate); n = 1; newrate = 0;}
        if(cl!=0xffff){SEND("controls: "); printuhex(cl); n = 1; cl = 0xffff;}
        if(br){SEND("break"); n = 1; br = 0;}
        if(n){newline(); transmit_tbuf();}*/
    }
    return 0;
}