/*
 * blinky.c
 *
 * Copyright 2018 Edward V. Emelianoff <eddy@sao.ru>
 *
 * 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 "uart.h"
#include "interrupts.h"

U8 UART_rx_cmd; // command received
volatile U8 uart_ready = 0;// command ready flag

/**
 * Send one byte through UART
 * @param byte - data to send
 */
void uart_send_byte(U8 byte){
    while(!(UART1_SR & UART_SR_TXE)); // wait until previous byte transmitted
    UART1_DR = byte;
}

void newline(){
    while(!(UART1_SR & UART_SR_TXE));
    UART1_DR = '\n';
}

void uart_write(char *str){
    while(*str){
        while(!(UART1_SR & UART_SR_TXE));
        UART1_CR2 |= UART_CR2_TEN;
        UART1_DR = *str++;
    }
}

/**
 * Read one byte from Rx buffer
 * @param byte - where to store data read
 * @return 1 in case of non-empty buffer
 */
U8 uart_read_cmd(U8 *byte){
    if(!uart_ready) // buffer is empty
        return 0;
    *byte = UART_rx_cmd;
    uart_ready = 0;
    return 1;
}

void printUint(U8 *val, U8 len){
    unsigned long Number = 0;
    U8 i = len;
    char ch;
    U8 decimal_buff[12]; // max len of U32 == 10 + \n + \0
    if(len > 4 || len == 3 || len == 0) return;
    for(i = 0; i < 12; i++)
        decimal_buff[i] = 0;
    decimal_buff[10] = '\n';
    ch = 9;
    switch(len){
        case 1:
            Number = *((U8*)val);
            break;
        case 2:
            Number = *((U16*)val);
        break;
        case 4:
            Number = *((unsigned long*)val);
        break;
    }
    do{
        i = Number % 10L;
        decimal_buff[ch--] = i + '0';
        Number /= 10L;
    }while(Number && ch > -1);
    uart_write((char*)&decimal_buff[ch+1]);
}

/**
 * print signed long onto terminal
 * max len = 10 symbols + 1 for "-" + 1 for '\n' + 1 for 0 = 13
 *
void print_long(long Number){
    U8 i, L = 0;
    char ch;
    char decimal_buff[12];
    decimal_buff[11] = 0;
    ch = 11;
    if(Number < 0){
        Number = -Number;
        L = 1;
    }
    do{
        i = Number % 10L;
        decimal_buff[--ch] = i + '0';
        Number /= 10L;
    }while(Number && ch > 0);
    if(ch > 0 && L) decimal_buff[--ch] = '-';
    uart_write(&decimal_buff[ch]);
}

U8 readInt(int *val){
    unsigned long T = Global_time;
    unsigned long R = 0;
    int readed;
    U8 sign = 0, rb, ret = 0, bad = 0;
    do{
        if(!uart_read_byte(&rb)) continue;
        if(rb == '-' && R == 0){ // negative number
            sign = 1;
            continue;
        }
        if(rb < '0' || rb > '9') break; // number ends with any non-digit symbol that will be omitted
        ret = 1; // there's at least one digit
        R = R * 10L + rb - '0';
        if(R > 0x7fff){ // bad value
            R = 0;
            bad = 0;
        }
    }while(Global_time - T < 10000); // wait no longer than 10s
    if(bad || !ret) return 0;
    readed = (int) R;
    if(sign) readed *= -1;
    *val = readed;
    return 1;
}

void error_msg(char *msg){
    uart_write("\nERROR: ");
    uart_write(msg);
    uart_send_byte('\n');
}

U8 U8toHEX(U8 val){
    val &= 0x0f;
    if(val < 10) val += '0';
    else val += 'a' - 10;
    return val;
}

void printUHEX(U8 val){
    uart_write("0x");
    uart_send_byte(U8toHEX(val>>4)); // MSB
    uart_send_byte(U8toHEX(val));    // LSB
}*/

void uart_init(){
    // PD5 - UART1_TX
    PORT(UART_PORT, DDR) |= UART_TX_PIN;
    PORT(UART_PORT, CR1) |= UART_TX_PIN;
// Configure UART
    // 8 bit, no parity, 1 stop (UART_CR1/3 = 0 - reset value)
    // 9600 on 16MHz: DIV=0x0693 -> BRR1=0x68, BRR2=0x03
    UART1_BRR1 = 0x68; UART1_BRR2 = 0x03;
    UART1_CR2 = UART_CR2_TEN | UART_CR2_REN | UART_CR2_RIEN; // Allow RX/TX, generate ints on rx
}