/*********************************************
* vim: set sw=8 ts=8 si et :
* Author: Guido Socher, Copyright: GPL v3
* This is the main program for the digital dc power supply
* 
* See http://www.tuxgraphics.org/electronics/
* 
* Chip type           : ATMEGA8
* Clock frequency     : Internal clock 8 Mhz 
*********************************************/
#include <avr/io.h>
#include <inttypes.h>
#include <avr/interrupt.h>
#define F_CPU 8000000UL  // 8 MHz
#include <util/delay.h>
#include <stdlib.h> 
#include <string.h> 
#include <avr/eeprom.h> 
#include "lcd.h"
#include "dac.h"
#include "kbd.h"
#include "uart.h"
#include "analog.h"
#include "hardware_settings.h"

// change this version string when you compile:
#define SWVERSION "ver: ddcp-0.6.3"
//#define DEBUGDISP 1

//debug LED:
// set output to VCC, red LED off
#define LEDOFF PORTD|=(1<<PORTD0)
// set output to GND, red LED on
#define LEDON PORTD&=~(1<<PORTD0)
// to test the state of the LED
#define LEDISOFF PORTD&(1<<PORTD0)
//
// the units are display units and work as follows: 100mA=10 5V=50
// The function int_to_dispstr is used to convert the intenal values
// into strings for the display
static int16_t measured_val[2]={0,0};
static int16_t set_val[2];
// the set values but converted to ADC steps
static int16_t set_val_adcUnits[2]; 
static uint8_t bpress=0;
// comment this out to use a debug LED on PD0 (RXD):
#define USE_UART 1
//
#ifdef USE_UART
#define UARTSTRLEN 10
static char uartstr[UARTSTRLEN+1];
static uint8_t uartstrpos=0;
static uint8_t uart_has_one_line=0;
#endif

void delay_ms_uartcheck(uint8_t ms)
// delay for a minimum of <ms> 
{
        uint8_t innerloop=1;
        while(ms){
#ifdef USE_UART
                if(uart_has_one_line==0 && uart_getchar_isr_noblock(&uartstr[uartstrpos])){
                        // ignore any white space:
                        if (uartstr[uartstrpos]==' ' || uartstr[uartstrpos]=='\t'){
                                goto NEXTCHAR;
                        }
                        if (uartstr[uartstrpos]=='\r'){
                                uartstr[uartstrpos]='\0';
                                uart_sendchar('\r'); // the echo line end
                                uart_sendchar('\n'); // the echo line end
                                //uart_sendchar('|'); uart_sendstr(&uartstr[0]);uart_sendchar('|'); //debug
                                uart_has_one_line=1;
                                goto NEXTCHAR;
                        }
                        uart_sendchar(uartstr[uartstrpos]);// echo back
                        /*
                                // debug
                                itoa(uartstr[uartstrpos],buf,10);
                                uart_sendchar('\r'); // the echo line end
                                uart_sendchar('\n'); // the echo line end
                                uart_sendstr(buf);
                                uart_sendchar('\r'); // the echo line end
                                uart_sendchar('\n'); // the echo line end
                        */
                        if (uartstr[uartstrpos]=='\b'){
                                if (uartstrpos>0){
                                        uartstrpos--;
                                        uart_sendchar(' '); // clear char on screen
                                        uart_sendchar('\b');
                                }
                        }else if (uartstr[uartstrpos]==0x7f){ // del
                                if (uartstrpos>0){
                                        uartstrpos--;
                                }
                        }else{
                                uartstrpos++;
                        }
                        if (uartstrpos>UARTSTRLEN){
                                uart_sendstr_P("\r\nERROR\r\n");
                                uartstrpos=0; // empty buffer
                                uartstr[0]='\0'; // just print prompt
                                uart_has_one_line=1; 
                        }
                }
#endif
NEXTCHAR:
                innerloop--;
                if (innerloop==0){
                        innerloop=45;
                        ms--;
                }
        }
}

// Convert an integer which is representing a float into a string.
// Our display is always 4 digits long (including one
// decimal point position). decimalpoint_pos defines
// after how many positions from the right we set the decimal point.
// The resulting string is fixed width and padded with leading space.
//
// decimalpoint_pos=2 sets the decimal point after 2 pos from the right: 
// e.g 74 becomes "0.74"
// The integer should not be larger than 999.
// The integer must be a positive number.
// decimalpoint_pos can be 0, 1 or 2
static void int_to_dispstr(uint16_t inum,char *outbuf,int8_t decimalpoint_pos){
        int8_t i,j;
        char chbuf[8];
        itoa(inum,chbuf,10); // convert integer to string
        i=strlen(chbuf);
        if (i>3) i=3; //overflow protection
        strcpy(outbuf,"   0"); //decimalpoint_pos==0
        if (decimalpoint_pos==1) strcpy(outbuf," 0.0");
        if (decimalpoint_pos==2) strcpy(outbuf,"0.00");
        j=4;
        while(i){
                outbuf[j-1]=chbuf[i-1];
                i--;
                j--;
                if (j==4-decimalpoint_pos){
                        // jump over the pre-set dot
                        j--;
                }
        }
}

// convert voltage values to adc values, disp=10 is 1.0V
// ADC for voltage is 11bit:
static int16_t disp_u_to_adc(int16_t disp){
        return((int16_t)(((float)disp * 204.7) / (ADC_REF * U_DIVIDER )));
}
// calculate the needed adc offset for voltage drop on the
// current measurement shunt (the shunt has about 0.75 Ohm =1/1.33 Ohm)
// use 1/1.2 instead of 1/1.3 because cables and connectors have as well
// a loss.
static int16_t disp_i_to_u_adc_offset(int16_t disp){
        return(disp_u_to_adc(disp/12));
}
// convert adc values to voltage values, disp=10 is 1.0V
// disp_i_val is needed to calculate the offset for the voltage drop over
// the current measurement shunt, voltage measurement is 11bit
static int16_t adc_u_to_disp(int16_t adcunits,int16_t disp_i_val){
        int16_t adcdrop;
        adcdrop=disp_i_to_u_adc_offset(disp_i_val);
        if (adcunits < adcdrop){
                return(0);
        }
        adcunits=adcunits-adcdrop;
        return((int16_t)((((float)adcunits /204.7)* ADC_REF * U_DIVIDER)+0.5));
}
// convert adc values to current values, disp=10 needed to be printed
// by the printing function as 0.10 A, current measurement is 10bit
static int16_t disp_i_to_adc(int16_t disp){
        return((int16_t) (((disp * 10.23)* I_RESISTOR) / ADC_REF));
}
// convert adc values to current values, disp=10 needed to be printed
// by the printing function as 0.10 A, current measurement is 10bit
static int16_t adc_i_to_disp(int16_t adcunits){
        return((int16_t) (((float)adcunits* ADC_REF)/(10.23 * I_RESISTOR)+0.5));
}

static void store_permanent(void){
        int16_t tmp;
        uint8_t changeflag=1;
        lcd_clrscr();
        if (eeprom_read_byte((uint8_t *)0x0) == 19){
                changeflag=0;
                // ok magic number matches accept values
                tmp=eeprom_read_word((uint16_t *)0x04);
                if (tmp != set_val[1]){
                        changeflag=1;
                }
                tmp=eeprom_read_word((uint16_t *)0x02);
                if (tmp != set_val[0]){
                        changeflag=1;
                }
        }
        delay_ms_uartcheck(1); // check for uart without delay
        if (changeflag){
                lcd_puts_P("setting stored");
                eeprom_write_byte((uint8_t *)0x0,19); // magic number
                eeprom_write_word((uint16_t *)0x02,set_val[0]);
                eeprom_write_word((uint16_t *)0x04,set_val[1]);
        }else{
                if (bpress> 2){
                        // display software version after long press
                        lcd_puts_P(SWVERSION);
                        lcd_gotoxy(0,1);
                        lcd_puts_P("tuxgraphics.org");
                }else{
                        lcd_puts_P("already stored");
                }
        }
        delay_ms_uartcheck(200);
        delay_ms_uartcheck(200);
        delay_ms_uartcheck(200);
}

// check the keyboard
static uint8_t check_buttons(void){
        uint8_t uartprint_ok=0;
        uint8_t cmdok=0;
#ifdef USE_UART
        char buf[21];
#endif
        //
#ifdef USE_UART
        if (uart_has_one_line){
                        if (uartstr[0]=='i' && uartstr[1]=='=' && uartstr[2]!='\0'){
                                set_val[0]=atoi(&uartstr[2]);
                                if(set_val[0]>I_MAX){
                                        set_val[0]=I_MAX;
                                }
                                if(set_val[0]<0){
                                        set_val[0]=0;
                                }
                                uartprint_ok=1;
                        }
                        // version
                        if (uartstr[0]=='v' && uartstr[1]=='e'){
                                uart_sendstr_p(P("  "));
                                uart_sendstr_p(P(SWVERSION));
                                uart_sendstr_p(P("\r\n"));
                                cmdok=1;
                        }
                        // store
                        if (uartstr[0]=='s' && uartstr[1]=='t'){
                                store_permanent();
                                uartprint_ok=1;
                        }
                        if (uartstr[0]=='u' && uartstr[1]=='=' && uartstr[2]!='\0'){
                                set_val[1]=atoi(&uartstr[2]);
                                if(set_val[1]>U_MAX){
                                        set_val[1]=U_MAX;
                                }
                                if(set_val[1]<0){
                                        set_val[1]=0;
                                }
                                uartprint_ok=1;
                        }
                        // help
                        if (uartstr[0]=='h' || uartstr[0]=='H'){
                                uart_sendstr_p(P("  Usage: u=V*10|i=mA/10|store|help|version\r\n"));
                                uart_sendstr_p(P("  Examples:\r\n"));
                                uart_sendstr_p(P("  set 6V: u=60\r\n"));
                                uart_sendstr_p(P("  max 200mA: i=20\r\n"));
                                cmdok=1;
                        }
                        if (uartprint_ok){
                                cmdok=1;
                                uart_sendstr_p(P("  ok\r\n"));
                        }
                        if (uartstr[0]!='\0' && cmdok==0){
                                uart_sendstr_p(P("  command unknown\r\n"));
                        }

                        int_to_dispstr(measured_val[1],buf,1);
                        uart_sendstr(buf);
                        uart_sendchar('V');
                        uart_sendchar(' ');
                        uart_sendchar('[');
                        int_to_dispstr(set_val[1],buf,1);
                        uart_sendstr(buf);
                        uart_sendchar(']');
                        uart_sendchar(',');
                        int_to_dispstr(measured_val[0],buf,2);
                        uart_sendstr(buf);
                        uart_sendchar('A');
                        uart_sendchar(' ');
                        uart_sendchar('[');
                        int_to_dispstr(set_val[0],buf,2);
                        uart_sendstr(buf);
                        uart_sendchar(']');
                        if (is_current_limit()){
                                uart_sendchar('I');
                        }else{
                                uart_sendchar('U');
                        }
                        uart_sendchar('>');
                uart_has_one_line=0;
                uartstrpos=0;
        }
#endif
        if (check_u_button(&(set_val[1]))){
                if(set_val[1]>U_MAX){
                        set_val[1]=U_MAX;
                }
                return(1);
        }
        if (check_i_button(&(set_val[0]))){
                if(set_val[0]>I_MAX){
                        set_val[0]=I_MAX;
                }
                return(1);
        }
        if (check_store_button()){
                store_permanent();
                return(2);
        };
        return(0);
}

int main(void)
{
        char out_buf[21];
        uint8_t i=0;
        uint8_t ilimit=0;

#ifndef USE_UART
        // debug led, you can not have an LED if you use the uart
        DDRD|= (1<<DDD0); // LED, enable PD0, LED as output
        LEDOFF;
#endif

        init_dac();
        lcd_init();
        init_kbd();
        set_val[0]=15;set_val[1]=50; // 150mA and 5V
        if (eeprom_read_byte((uint8_t *)0x0) == 19){
                // ok magic number matches accept values
                set_val[1]=eeprom_read_word((uint16_t *)0x04);
                set_val[0]=eeprom_read_word((uint16_t *)0x02);
        }
#ifdef USE_UART
        uart_init();
#endif
        sei();
        init_analog();
        while (1) {
                i++;
                // due to electrical interference we can get some
                // garbage onto the display especially if the power supply
                // source is not stable enough. We can remedy it a bit in
                // software with an ocasional reset:
                if (i==50){ // not every round to avoid flicker
                        lcd_reset();
                        i=0;
                }
                lcd_home();
                // current
                measured_val[0]=adc_i_to_disp(getanalogresult(0));
                set_val_adcUnits[0]=disp_i_to_adc(set_val[0]);
                set_target_adc_val(0,set_val_adcUnits[0]);
                // voltage
                measured_val[1]=adc_u_to_disp(getanalogresult(1),measured_val[0]);
                set_val_adcUnits[1]=disp_u_to_adc(set_val[1])+disp_i_to_u_adc_offset(measured_val[0]);
                set_target_adc_val(1,set_val_adcUnits[1]);
                ilimit=is_current_limit();

                        
                // voltage
#ifdef DEBUGDISP
                itoa(getanalogresult(1),out_buf,10);
#else
                int_to_dispstr(measured_val[1],out_buf,1);
#endif
                lcd_puts(out_buf);
                lcd_puts("V [");
#ifdef DEBUGDISP
                itoa(set_val_adcUnits[1],out_buf,10);
#else
                int_to_dispstr(set_val[1],out_buf,1);
#endif
                lcd_puts(out_buf);
                lcd_putc(']');
                delay_ms_uartcheck(1); // check for uart without delay
                if (!ilimit){
                        // put a marker to show which value is currenlty limiting
                        lcd_puts("<- ");
                }else{
                        lcd_puts("   ");
                }

                // current
                lcd_gotoxy(0,1);
#ifdef DEBUGDISP
                itoa(getanalogresult(0),out_buf,10);
#else
                int_to_dispstr(measured_val[0],out_buf,2);
#endif
                lcd_puts(out_buf);
                lcd_puts("A [");
#ifdef DEBUGDISP
                itoa(set_val_adcUnits[0],out_buf,10);
#else
                int_to_dispstr(set_val[0],out_buf,2);
#endif
                lcd_puts(out_buf);
                lcd_putc(']');
                if (ilimit){
                        // put a marker to show which value is currenlty limiting
                        lcd_puts("<- ");
                }else{
                        lcd_puts("   ");
                }

                // the buttons must be responsive but they must not 
                // scroll too fast if pressed permanently
                if (check_buttons()==0){
                        // no buttons pressed
                        delay_ms_uartcheck(80);
                        bpress=0;
                        if (check_buttons()==0){
                                // no buttons pressed
                                delay_ms_uartcheck(80);
                        }else{
                                bpress++;
                                delay_ms_uartcheck(180);
                                delay_ms_uartcheck(180);
                                delay_ms_uartcheck(180);
                                delay_ms_uartcheck(180);
                        }
                }else{
                        // button press
                        if (bpress > 10){
                                // somebody pressed permanetly the button=>scroll fast
                                delay_ms_uartcheck(120);
                        }else{
                                bpress++;
                                delay_ms_uartcheck(180);
                                delay_ms_uartcheck(180);
                                delay_ms_uartcheck(180);
                                delay_ms_uartcheck(180);
                        }
                }
        }
        return(0);
}