// led blink example Copyright (C) 2014 Diego Herranz

#define NO_BIT_DEFINES
#include <pic14regs.h>
#include <stdint.h> 
#include <stdbool.h>

// Oscillator Selection bits (INTOSCIO oscillator: I/O function on RA6/OSC2/CLKOUT pin, I/O function on RA7/OSC1/CLKIN),
// disable watchdog,
// and DO NOT disable low voltage programming.
// The rest of fuses are left as default.
__code uint16_t __at (_CONFIG1) __configword = _FOSC_INTOSC & _CLKOUTEN_OFF & _WDTE_OFF & _BOREN_ON & _CP_OFF;

#define LED_PORT PORTAbits.RA5
#define HASCH PIR1bits.RCIF

// board layout:
// mosfets clockwise from power feed:
// RA5, RA4, RC2, RC3
// 'input' pin: RC5

// microsecond delay.
static inline void delay(uint8_t us)
{
  TMR1L = 0;
  while(TMR1L < us && !HASCH);
}
#define ADDTOUINT16(REG, LIT) __asm \
  BANKSEL REG \
  MOVLW LIT \
  ADDWF _##REG##L, F \
  CLRW \
  ADDWFC _##REG##H, F \
  __endasm
#define SUBFROMUINT16(REG, LIT) __asm \
  BANKSEL REG \
  MOVLW LIT \
  SUBWF _##REG##L, F \
  CLRW \
  SUBWFB _##REG##H, F \
  __endasm
#define PPSO_PWM1 3
#define STX 0x02
#define ETX 0x03
uint8_t animating = 0;
struct animate_data {
  uint8_t stepH;
  uint8_t stepL;
  uint8_t countH;
  uint8_t countL;
  uint8_t interval;
} animate_data[4];
void handle_input(unsigned char input) {
  static uint8_t cnt = 0;
  static uint8_t buf[7];
  // STX CMD A B C D PARITY ETX
  // STX 01__ abcd PWMxDCH PWMxDCL PWMxPRH  PWMxPRL ignored  PARITY ETX // abcd = applicable pwm's
  // STX 11__ abcd stepH   stepL   countH  countL   interval PARITY ETX
  switch (cnt) {
  case 0:
    if (input == STX) {
      cnt++;
    }
    return;
  case 1: case 2: case 3: case 4: case 5: case 6:
    buf[cnt - 1] = input;
    cnt++;
    return;
  case 7:
    // check parity
    cnt++;
    return;
  case 8:
    cnt = 0;
    if (input != ETX) return;
    if ((buf[0] & 0xC0) == 0x40) {
      // echo -n -e '\x02O\x90\x13\xFF\xFF\x00\x00\x03' > /dev/ttyUSB0
      // SET packet
      if (buf[0] & 0x8) {
        // A
        PWM1DCH = buf[1];
        PWM1DCL = buf[2];
        PWM1PRH = buf[3];
        PWM1PRL = buf[4];
        PWM1LDCON  = 0x80;  // load armed
      }
      if (buf[0] & 0x4) {
        // B
      }
      if (buf[0] & 0x2) {
        // C
      }
      if (buf[0] & 0x1) {
        // D
      }
      return;
    }
    if ((buf[0] & 0xC0) == 0xC0) {
      // ANIMATE packet
      if (buf[0] & 0x8) {
        // A
        animate_data[0].stepH = buf[1];
        animate_data[0].stepL = buf[2];
        animate_data[0].countH = buf[3];
        animate_data[0].countL = buf[4];
        animate_data[0].interval = buf[5];
        animating |= 1;
      }
    }
  }  
}
unsigned char getch() {
  // will freeze if you call this without any byte being available
  while(PIR1bits.RCIF == 0);
  PIR1bits.RCIF = 0;
  // framing error: TODO
  // if (RCSTAbits.FERR) yolo
  
  // deal with overflow error
  // TODO: should you do this before reading RCREG?
  if (RCSTAbits.OERR) {
    RCSTAbits.CREN = 0;
    RCSTAbits.CREN = 1;
  }
  return RCREG;
  
}
// messages:
// set PR DC
// fade period step

void main(void)
{
  OSCCON = 0xf0;
  TRISCbits.TRISC5 = 1;
  T1CON = 0x31; // timer1 at 1 mhz, so 1us
  ANSELA = 0;
  ANSELC = 0;
  TRISA = 0;
  //SLRCONC = 0;
  LED_PORT = 0;
    PWM1CLKCON = 0x00;  // From Fosc w/o prescaler
    PWM1PRH = PWM1PRL = 0xFF; // period: 32 mhz / 65535 = 488 Hz
    PWM1PH     = 0;
    PWM1DCH = PWM1DCL = 0;
    PWM1OF     = 0;
    

    PWM1INTE   = 0x00;  // no interrupts enabled
    PWM1INTF   = 0x00;  // clear interrupt flag
    PWM1LDCON  = 0x80;  // load armed
    PWM1OFCON  = 0x00;  // independent run mode
    PWM1CON    = 0x80;  // enable, standard PWM mode, active high output

    RA5PPS = PPSO_PWM1;

    BAUDCONbits.BRG16 = 1;
    TXSTAbits.BRGH = 0;
    SPBRGH = 3; // 832, baud rate 2400.96
    SPBRGL = 64;
    RCSTAbits.CREN = 1;
    TXSTAbits.SYNC = 0;
    RCSTAbits.SPEN = 1;
    while(1) {
      if (HASCH) handle_input(getch());
      if (animating & 0x1) {
        ADDTOUINT16(PWM1DC, 1);
        PWMLD = 1;
      }
      delay(50);
    }

    /* while(1) { */
    /*   while (PWM1DCL < 0xFF || PWM1DCH < 0xFE) { */
    /*     ADDTOUINT16(PWM1DC, 1); */
          
    /*     PWMLD = 1; */
    /*     delay(50); */
    /*   } */
    /*   while (PWM1DCL > 0 || PWM1DCH > 0) { */
    /*     SUBFROMUINT16(PWM1DC, 1); */
    /*     PWMLD = 1; */
    /*     delay(50); */
    /*   } */
    /* } */
}