main.h

/**
 * main.h
 *
 * Main module definition file
 *
 * Author: Luis Teixeira (creationfactory.co)

 * Licence and copyright notice:
 *
 * Copyright 2020 Luis Teixeira
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, softwar
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Created on 11th June 2020, 14:38
 */

#ifndef MAIN_H
#define	MAIN_H

#ifdef	__cplusplus
extern "C" {
#endif

#include <pic16f628a.h>
#include "pic.h"

#define LOW_SPEED

#ifdef LOW_SPEED
#define BAUD_RATE 9600
#else
#define BAUD_RATE 115200 // note: 115200 bps is not achievable using the 4 MHz internal oscillator.
#endif

/*
 * SPBRG should be calculated as:
 * 
 * SPBRG = (unsigned char) ((_XTAL_FREQ / 16) / BAUD_RATE) - 1;
 * 
 * For example for a 115200 baud rate and a 20 MHz clock frequency
 * we have the following:
 * 
 * SPBRG = ((20 000 000 / 16) / 115200) - 1
 * SPBRG = 9.850
 * 
 * If we round up to the nearest integer, we have:
 * 
 * SP_BAUD_TIMER=10
 * 
 */

#ifdef LOW_SPEED
#define SP_BAUD_TIMER 25 // For baud rate = 9600 and 4 MHz internal oscillator
#else
#define SP_BAUD_TIMER 10 // For baud rate = 1125200 and 20 MHz crystal
#endif

/*
 * The offset can be calculated as follows:
 * 
 * TMR1_OFFSET = 65535 - (_XTAL_FREQ / (Prescaler * 40))
 *
 * e.g. using a 20 MHz crystal and 1:8 prescaler:
 * 
 * 0x0BDB = 65535 - ( 20 000 000 / (8 * 40))
 */
#ifdef LOW_SPEED
#define TMR1_OFFSET             0xCF2B      // Offset for calibrating the timer (4 MHz internal oscillator).
#else
#define TMR1_OFFSET             0x0BDB      // Offset for calibrating the timer (20 MHz crystal)    
#endif

// (watchdog) timer related settings:

#define WT_TIMEOUT                  6000        // timeout period (in tenths of seconds) for the watchdog to trigger
#define POWER_OFF_DURATION          8000        // ms to keep power off for resetting the target device
#define POWER_OFF_DELAY             3000        // delay (in ms) between the poweroff command and actually powering off the device
#define WDT_PREFIX_LENGTH           15
#define WDT_CMD_LENGTH              16
    
#define SHUTDOWN_CMD                "poweroff -f\r\n"
#define SHUTDOWN_CMD_LEN            13
    
    
unsigned int timerCount;

// Prefix for every WDT command (relatively hard to occur in the host
// serial output, other than from the job that resets the watchdog):
const unsigned char *wdtPrefix = "WDT_BhAyycbmEi_";

// Commands accepted by the WDT:

/*
 
 This command is used for resetting the WDT:

*/
const unsigned char resetWdtCmd = '1';

/*
 
 This command is used for disabling the WDT:

 */
const unsigned char disableWdtCmd = '2';

/*
 
 This command is used for enabling the WDT again:
 
 */
unsigned char enableWdtCmd = '3';

void init(void);
void resetTimer(void);
void enableTimer(void);
void disableTimer(void);
void serialWrite(char* str, char length);

/**
 * This function checks if the bytes we are receiving are part of the string
 * we are expecting:
 * 
 **/
void tokenMatchLoop(void);

void isr(void);


#ifdef	__cplusplus
}
#endif

#endif	/* MAIN_H */