/*
 * File:   main.c
 * Author: boos
 *
 * Created on August 12, 2023, 7:39 PM
 */

// CONFIG1
#pragma config FOSC = INTOSC    // Oscillator Selection Bits (INTOSC oscillator: I/O function on CLKIN pin)
#pragma config WDTE = OFF       // Watchdog Timer Enable (WDT disabled)
#pragma config PWRTE = ON       // Power-up Timer Enable (PWRT enabled)
#pragma config MCLRE = OFF      // MCLR Pin Function Select (MCLR/VPP pin function is digital input)
#pragma config CP = OFF         // Flash Program Memory Code Protection (Program memory code protection is disabled)
#pragma config BOREN = OFF      // Brown-out Reset Enable (Brown-out Reset disabled)
#pragma config CLKOUTEN = OFF   // Clock Out Enable (CLKOUT function is disabled. I/O or oscillator function on the CLKOUT pin)
#pragma config IESO = OFF       // Internal/External Switchover Mode (Internal/External Switchover Mode is disabled)
#pragma config FCMEN = OFF      // Fail-Safe Clock Monitor Enable (Fail-Safe Clock Monitor is disabled)

// CONFIG2
#pragma config WRT = OFF        // Flash Memory Self-Write Protection (Write protection off)
#pragma config CPUDIV = NOCLKDIV// CPU System Clock Selection Bit (NO CPU system divide)
#pragma config USBLSCLK = 48MHz // USB Low Speed Clock Selection bit (System clock expects 48 MHz, FS/LS USB CLKENs divide-by is set to 8.)
#pragma config PLLMULT = 3x     // PLL Multipler Selection Bit (3x Output Frequency Selected)
#pragma config PLLEN = ENABLED  // PLL Enable Bit (3x or 4x PLL Enabled)
#pragma config STVREN = OFF     // Stack Overflow/Underflow Reset Enable (Stack Overflow or Underflow will not cause a Reset)
#pragma config BORV = LO        // Brown-out Reset Voltage Selection (Brown-out Reset Voltage (Vbor), low trip point selected.)
#pragma config LPBOR = OFF      // Low-Power Brown Out Reset (Low-Power BOR is disabled)
#pragma config LVP = OFF        // Low-Voltage Programming Enable (Low-voltage programming disabled)

#include <xc.h>


// abbreviations for locations of external devices
// (this is not necessary, but useful)
#define WS2812_DATA  RC2

// clock frequency (for __delay_ms function)
#define _XTAL_FREQ 48000000

// functions to control the WS2812 NeoPixel LEDs
#define WS2812_send_bit(b) WS2812_DATA=1; NOP(); NOP(); NOP(); WS2812_DATA=b; NOP(); NOP(); NOP(); NOP(); WS2812_DATA=0; NOP(); NOP(); NOP(); NOP();
void WS2812_send_byte (unsigned char b);
void WS2812_send_RGB (unsigned char r, unsigned char g, unsigned char b);


// *****
// main function
void main (void) {
    
    
    // *****
    // set up internal oscillator to run at 48 MHz
    
    // set the SCS settings (system clock select)
    // to use the frequency specified in configuration word (line 22)
    SCS0 = 0;
    SCS1 = 0;
    
    // set to 16 MHz configuration
    IRCF0 = 1;
    IRCF1 = 1;
    IRCF2 = 1;
    IRCF3 = 1;
    
    // enable PLL to result in 48MHz
    // (PLL is set to 3x in line 23)
    SPLLEN = 1;
    
    
    // *****
    // set up peripherals
    
    // WS2812_DATA is an output
    TRISC2 = 0;
    
    // turn off all analog to digital converters
    ANSC2 = 0;

    
    // *****
    // main loop
    while (1) {
        
        // we need to turn interrupts OFF during data transmission because this part is time critical
        GIE = 0;
        
        // wait a bit, just in case
        __delay_ms(1);
        
        // send hours data
        WS2812_send_RGB(255, 128, 0); WS2812_send_RGB(0, 0, 0); WS2812_send_RGB(0, 0, 0); WS2812_send_RGB(0, 0, 0); WS2812_send_RGB(0, 0, 0); WS2812_send_RGB(0, 0, 255);
        WS2812_send_RGB(0, 0, 255); WS2812_send_RGB(0, 0, 255); WS2812_send_RGB(0, 0, 255); WS2812_send_RGB(0, 0, 0); WS2812_send_RGB(0, 0, 255); WS2812_send_RGB(0, 0, 0);
        WS2812_send_RGB(0, 0, 255); WS2812_send_RGB(0, 0, 0); WS2812_send_RGB(0, 0, 255); WS2812_send_RGB(0, 0, 255); WS2812_send_RGB(0, 0, 0); WS2812_send_RGB(0, 0, 255);
        
        // wait a bit, just in case
        __delay_ms(1);
        
        // now it is safe to turn interrupts back on
        GIE = 1;
        
    }
    
    return;
    
}

// send out a byte b in WS2812 protocol
void WS2812_send_byte (unsigned char b) {

    if (b & 0b10000000) { WS2812_send_bit(1); } else { WS2812_send_bit(0); }
    if (b & 0b01000000) { WS2812_send_bit(1); } else { WS2812_send_bit(0); }
    if (b & 0b00100000) { WS2812_send_bit(1); } else { WS2812_send_bit(0); }
    if (b & 0b00010000) { WS2812_send_bit(1); } else { WS2812_send_bit(0); }
    if (b & 0b00001000) { WS2812_send_bit(1); } else { WS2812_send_bit(0); }
    if (b & 0b00000100) { WS2812_send_bit(1); } else { WS2812_send_bit(0); }
    if (b & 0b00000010) { WS2812_send_bit(1); } else { WS2812_send_bit(0); }
    if (b & 0b00000001) { WS2812_send_bit(1); } else { WS2812_send_bit(0); }
    
}

// send red, green, and blue values in WS2812 protocol
void WS2812_send_RGB (unsigned char r, unsigned char g, unsigned char b) {

    WS2812_send_byte(g);
    WS2812_send_byte(r);
    WS2812_send_byte(b);
    
}