/*
 * File:    main.c
 * Author:  Naoki Pross 4E
 * Date:    08.01.2018
 * Target:  PIC18F44K22
 * Version  1.0
 * 
 * Description:
 * 
 * Main program for the Xylophone project.
 */

// PIC18F44K22 Configuration Bit Settings
// 'C' source line config statements

// CONFIG1H
// Oscillator Selection bits (Internal oscillator block)
#pragma config FOSC = INTIO67    
// 4X PLL Enable (Oscillator multiplied by 4)
#pragma config PLLCFG = ON      
// Primary clock enable bit (Primary clock is always enabled)
#pragma config PRICLKEN = ON    
// Fail-Safe Clock Monitor Enable bit (Fail-Safe Clock Monitor disabled)
#pragma config FCMEN = OFF      
// Internal/External Oscillator Switchover bit (Oscillator Switchover mode disabled)
#pragma config IESO = OFF       

// CONFIG2L
// Power-up Timer Enable bit (Power up timer disabled)
#pragma config PWRTEN = OFF     
// Brown-out Reset Enable bits (Brown-out Reset enabled in hardware only (SBOREN is disabled))
#pragma config BOREN = SBORDIS  
// Brown Out Reset Voltage bits (VBOR set to 1.90 V nominal)
#pragma config BORV = 190       

// CONFIG2H
// Watchdog Timer Enable bits (WDT is always enabled. SWDTEN bit has no effect)
#pragma config WDTEN = OFF      
// Watchdog Timer Postscale Select bits (1:32768)
#pragma config WDTPS = 32768    

// CONFIG3H
// CCP2 MUX bit (CCP2 input/output is multiplexed with RC1)
#pragma config CCP2MX = PORTC1  
// PORTB A/D Enable bit (PORTB<5:0> pins are configured as analog input channels on Reset)
#pragma config PBADEN = ON      
// P3A/CCP3 Mux bit (P3A/CCP3 input/output is multiplexed with RB5)
#pragma config CCP3MX = PORTB5  
// HFINTOSC Fast Start-up (HFINTOSC output and ready status are not delayed by the oscillator stable status)
#pragma config HFOFST = ON      
// Timer3 Clock input mux bit (T3CKI is on RC0)
#pragma config T3CMX = PORTC0   
// ECCP2 B output mux bit (P2B is on RD2)
#pragma config P2BMX = PORTD2   
// MCLR Pin Enable bit (MCLR pin enabled, RE3 input pin disabled)
#pragma config MCLRE = EXTMCLR  

// CONFIG4L
// Stack Full/Underflow Reset Enable bit (Stack full/underflow will cause Reset)
#pragma config STVREN = ON      
// Single-Supply ICSP Enable bit (Single-Supply ICSP enabled if MCLRE is also 1)
#pragma config LVP = ON         
// Extended Instruction Set Enable bit (Instruction set extension and Indexed Addressing mode disabled (Legacy mode))
#pragma config XINST = OFF      

// CONFIG5L
// Code Protection Block 0 (Block 0 (000800-001FFFh) not code-protected)
#pragma config CP0 = OFF        
// Code Protection Block 1 (Block 1 (002000-003FFFh) not code-protected)
#pragma config CP1 = OFF        
// Code Protection Block 2 (Block 2 (004000-005FFFh) not code-protected)
#pragma config CP2 = OFF        
// Code Protection Block 3 (Block 3 (006000-007FFFh) not code-protected)
#pragma config CP3 = OFF        

// CONFIG5H
// Boot Block Code Protection bit (Boot block (000000-0007FFh) not code-protected)
#pragma config CPB = OFF        
// Data EEPROM Code Protection bit (Data EEPROM not code-protected)
#pragma config CPD = OFF        

// CONFIG6L
// Write Protection Block 0 (Block 0 (000800-001FFFh) not write-protected)
#pragma config WRT0 = OFF       
// Write Protection Block 1 (Block 1 (002000-003FFFh) not write-protected)
#pragma config WRT1 = OFF       
// Write Protection Block 2 (Block 2 (004000-005FFFh) not write-protected)
#pragma config WRT2 = OFF       
// Write Protection Block 3 (Block 3 (006000-007FFFh) not write-protected)
#pragma config WRT3 = OFF       

// CONFIG6H
// Configuration Register Write Protection bit (Configuration registers (300000-3000FFh) not write-protected)
#pragma config WRTC = OFF       
// Boot Block Write Protection bit (Boot Block (000000-0007FFh) not write-protected)
#pragma config WRTB = OFF       
// Data EEPROM Write Protection bit (Data EEPROM not write-protected)
#pragma config WRTD = OFF       

// CONFIG7L
// Table Read Protection Block 0 (Block 0 (000800-001FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR0 = OFF      
// Table Read Protection Block 1 (Block 1 (002000-003FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR1 = OFF      
// Table Read Protection Block 2 (Block 2 (004000-005FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR2 = OFF      
// Table Read Protection Block 3 (Block 3 (006000-007FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR3 = OFF      

// CONFIG7H
// Boot Block Table Read Protection bit (Boot Block (000000-0007FFh) not protected from table reads executed in other blocks)
#pragma config EBTRB = OFF      

// #pragma config statements should precede project file includes.
// Use project enums instead of #define for ON and OFF.

#define _XTAL_FREQ 64000000

#include "rs232.h"
#include "midi.h"

#include <xc.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>


#define NOTE_MIN_LENGTH_MS 10
#define NOTE_MASK 0xFFFFFF00

#define NOTES 16

// note: when selecting an instrument, subtract 1 (1 - 128 => 0 - 127)
// see https://www.midi.org/specifications/item/gm-level-1-sound-set
#define MIDI_INSTRUMENT     9
// note: when selecting a channel, subtract 1 (1 - 128 => 0 - 127)
#define MIDI_CHANNEL        0

#define MIDI_NOTE_SPEED     127 // max is 0x7F


//#define DEBUG


/* global variables */
volatile uint32_t keys_data[NOTES];
// flags to notify the main program
volatile uint16_t keypresses = 0;

/* function prototypes */
int eusart_write_midi(const midi_message_t *pkt);

/* interrupt service routine */
interrupt void isr(void)
{
    unsigned char i, data_a, data_b;

#ifdef DEBUG
    PORTDbits.RD3 = 0;
#endif
    
    if (PIR1bits.TMR2IF) {
        data_a = PORTA;
        data_b = PORTB;

        i = 7;
        do {
            // read the data and append it at the end of keys_data[i]
            keys_data[i] = (keys_data[i] << 1) | ((data_a >> i) & 0x01);
            keys_data[i + 8] = (keys_data[i + 8] << 1) | ((data_b >> i) & 0x01);

            // TODO same for PORTD when the steps board is printed

            // set flags
            keypresses |= (keys_data[i] && !(keys_data[i] & NOTE_MASK))<<i;
            keypresses |= (keys_data[i + 8] && !(keys_data[i + 8] & NOTE_MASK))<<(i + 8);

        } while (i--);
        
#ifdef DEBUG
        // debug stuff
        PORTDbits.RD4 = PORTAbits.RA0;
        PORTDbits.RD2 = (keys_data[0] && !(keys_data[0] & NOTE_MASK));
#endif
        
        // reset interrupt flag
        PIR1bits.TMR2IF = 0;
    }

#ifdef DEBUG
    PORTDbits.RD3 = 1;
#endif
}

/* hardware configuration (inlined) */
inline void init_hw(void)
{
    di();
    
    /* PLL / FOSC configuration */
    // enable PLL
    OSCTUNEbits.PLLEN = 1;
    // set FOSC to HFINTOSC (max frequency)
    OSCTUNEbits.TUN = 0b011111;
    // set 16 MHz oscillator, datasheet p.30
    OSCCONbits.IRCF = 0b111;
    // select primary clock (with PLL)
    OSCCONbits.SCS = 0b00;
    
    /* i/o initializazion */
    // disable all ADCs
    ANSELA = 0x00;
    ANSELB = 0x00;
    ANSELC = 0x00;
    ANSELD = 0x00;

    // set ports as input
    TRISA = 0xFF;
    TRISB = 0xFF;
    
#ifdef DEBUG
    TRISDbits.TRISD1 = 0;
    TRISDbits.TRISD2 = 0;
    TRISDbits.TRISD3 = 0;
    TRISDbits.TRISD4 = 0;
    
    // LED
    PORTDbits.RD1 = 1;
    // TEST OUTPUT 1
    PORTDbits.RD2 = 0;
    // TEST OUTPUT 2
    PORTDbits.RD3 = 1;
    // TEST OUTPUT 3
    PORTDbits.RD4 = 0;
#endif 
    
    /* timer configuration */
    // timer 2 comp value
    PR2 = 128;
    // postscaler 1:2
    T2CONbits.T2OUTPS = 0b0001;
    // prescaler 1:16
    T2CONbits.T2CKPS = 0b11;
    // start timer
    T2CONbits.TMR2ON = 1;
    
    // timer 2 interrupts
    PIE1bits.TMR2IE = 1;
    PIR1bits.TMR2IF = 0;

    // enable peripheral interrupts
    INTCONbits.PEIE = 1;
    
    /* serial configuration */
    eusart1_init();
    eusart2_init();
}


/* main program */
void main(void)
{
    unsigned i;
    midi_message_t conf_message, message;
    
    /* setup hardware */
    init_hw();
   
    /* setup software */
    memset(keys_data, 0, sizeof(keys_data));
    
    ei();
    
#ifdef DEBUG
    PORTDbits.RD1 = 0;
#endif
   
    /* midi device configuration */
    conf_message.status = PROGRAM_CHANGE;
    conf_message.channel = MIDI_CHANNEL;
    conf_message.data[0] = MIDI_INSTRUMENT;
    conf_message.data_size = 1;
    
    midi_note_on(&message, MIDI_CHANNEL, midi_notes_steps_table[0], MIDI_NOTE_SPEED);
    
    __delay_ms(500);
    eusart_write_midi(&conf_message);
    
    /* main loop */
    while (1) {
        // check flags
        for (i = 0; i < NOTES; i++) {
            if (keypresses & (1<<i)) {
                
                // dirty hack to avoid the slow call stack, correct version commented below
                message.data[0] = midi_notes_steps_table[i];
                //midi_note_on(&message, MIDI_CHANNEL, MIDI_SCALE_START + i, MIDI_NOTE_SPEED);
                
                eusart_write_midi(&message);
                
                // wait for the minimum note length
                
                // TODO improve;
                // with this system packets will be delayed by
                // NOTE_MIN_LENGTH_MS * NOTES milliseconds relative to the actual measurement
                __delay_ms(NOTE_MIN_LENGTH_MS);
                
                // unset flag
                keypresses &= ~(1<<i);
            }
        }
    }
}


int eusart_write_midi(const midi_message_t *pkt)
{
    size_t length;
    uint8_t *data;
    
    if (pkt == NULL) {
        return -1;
    }
    
    length = pkt->data_size;
    data = (uint8_t *) pkt->data;
    
    eusart2_putch((char)((pkt->status << 4) | pkt->channel));
    
    while (length--) {
        eusart2_putch((char) *(data++));
    }
    
    return 0;
}