// tab space = 4
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/*-----------------------------------------------------------------------------
  FILE NAME: Demo1.c
-----------
DESCRIPTION: Demo program for R8C/17 SKP
-----------
    DETAILS: This demo has two modes of operation: light and temperature.
			 Switch S1 is used to determine which demo is running.

			 i) Light: If S1's actuator is towards pushbutton S2, the light
			 demo is running. The LEDs sequential blink speed varies depending
			 on the light level detected using the CdS Cell (the brighter it
			 is, the faster the blink speed becomes and vice versa). Pressing
			 S2 changes the blinking sequence of the LEDs.

			 ii) Temperature: If S1's actuator is away from S2, the temperature
			 demo is running. Temperature is sampled and the LEDs are lit based
			 on rising or falling temperature. When the temperature of the
			 Thermistor stays constant the yellow LED is lit. When the
			 temperature increases, the Red LED is lit, and when the temperature
			 decreases, the Green LED is lit.

------------------
 Revision History
------------------
   1.0 Nov 19, 2004
       Initial Version
-----------------------------------------------------------------------------*/

#include "skp8c17_bsp.h"

/* Function Prototypes */
void main(void);
void mcu_init(void);	/* in mcu_init.c */
void tmrZ_isr(void);

// bits 0:RED, 1:YLW, 2:GRN
// values 1:OFF, 0 ON)
const char led_pattern1[] = {6,4,0,1,3,7,3,1,0,4,6,7};
const char led_pattern2[] = {6,5,3,5};

/*****************************************************************************
Name       : main
Parameters : none
Returns    : nothing
Description: Main Program
*****************************************************************************/
void main(void)
{
	mcu_init();				/* initialize MCU */
	ENABLE_LEDS				/* LED initialization */

	/* Configure Timer X - for Timer Z underflow count source */
	txmr = 0x00;		// timer mode
	prex = 0xFF;		// X prescaler value (n)
	tx = 0x1F;			// X register value (m)
	tcss = 0x21;		// use f8 for timer X, underflow of timer X for Z

	/* Configure Timer Z - for ADC data acquisition */
	tzmr = 0x00;		// timer mode
	prez = 0x01;		// Z prescaler value (q)
	tzpr = 0x01;		// Z primary register initial value (p)
	//tcss = 0x21;		// use f8 for timer Z (already set above)

	// Timer mode output rate = ((n+1)(m+1)(q+1)(p+1))/(20Mhz/8)

  	/* Configure ADC - AN10 (CdS cell) */
	adcon0 = 0x96;  	// AN10, one shot mode, fAD/2
	adcon1 = 0x20;		// 8-bit mode, Vref connected.
	adcon2 = 0x01;		// Sample and hold enabled

  	DISABLE_IRQ			// disable irqs before setting irq registers
  	tzic = 2;			// Set the timer Z's interrupt priority to level 2
   	ENABLE_IRQ			// enable interrupts

	txs = 1;			// Start timer X
   	tzs = 1;			// Start timer Z

	while(1)
	{
		/* loop forever */
		/* All action takes place in Timer interrupt routine */
	}
}

/*****************************************************************************
Name:   tmrZ_isr
Parameters:
Returns:
Description: Timer Z ISR sets AD channel based on slider sw. value,
             gets a new AD sample and preloads timer X.
             It also varies the LED's D1, D2, & D3 sequentially by controlling the LED
			 control variable.
*****************************************************************************/
#pragma INTERRUPT	tmrZ_isr
void tmrZ_isr(void)
{
	/* Static Variables (retains values between interrupts */
	static char pattern_index = 0;		// Current index of LED pattern array
	static char last_temp_value = 128;	// Last A/D temperature value taken

	/* Auto Variable (created on stack each time ) */
	unsigned char current_temp_value;	// Used to hold the current A/D temperature value
	union byte_def led_value;		// Next led value to display
									// NOTE: "union byte_def" is defined in
									// the sfr header file

	/* Read slider switch S1 to determine current mode */
	if( S1 == 0 )	// Switch S1 towards button
	{
		/*** MEASURE LIGHT USING CDS CELL ***/

		ch0 = 0;		// measure light level
		adcon1 = 0x20;	// 8-bit mode, Vref connected.
		adst = 1;		// Start A2D conversion
		while(adst);	// wait for A/D conversion start bit to return to 0
		tzpr = adl;		// read AD value and preload Timer Z to vary the LED switching rate

		/* Advance to the next LED pattern and display */
		/* The current position of the button determines the pattern to use */
		if( S2 )	// Button UP?
		{
			if(++pattern_index >= 12)
				pattern_index = 0;	// return to initial state
			led_value.byte = led_pattern1[pattern_index];
		}
		else			// Button DOWN
		{
			if(++pattern_index >= 4)
				pattern_index = 0;	// return to initial state
			led_value.byte = led_pattern2[pattern_index];
		}

		/* Set LEDs */
		RED_LED = led_value.bit.b0;		// Bit 0 is RED LED value
		YLW_LED = led_value.bit.b1;		// Bit 1 is YELLOW LED value
		GRN_LED = led_value.bit.b2;		// Bit 2 is GREEN LED value
	}
	else
	{
		/*** MEASURE TEMPERATURE USING THERMISTER ***/

		tzpr = 0x40;		/* Fixed sample rate */

		/* Read temperature */
		ch0 = 1;			// measure temperature
   		adcon1 = 0x28;		// 10-bit mode, Vref connected,	fAD/2
		adst = 1;			// Start A2D conversion
		while(adst);		// wait for A/D conversion start bit to return to 0

		/* Reduce 10-bit AD sample to 8-bits by removing the last 2 bits */
		current_temp_value = ad >> 2;

		/* Change LEDs if temperature has changed */
   		RED_LED = YLW_LED = GRN_LED = LED_OFF;			// All LEDs OFF
		if (last_temp_value == current_temp_value)
			YLW_LED = LED_ON;		// yellow LED ON - temp stable
		else if (last_temp_value > current_temp_value)
	    	RED_LED = LED_ON;		// red LED ON - temp rising
		else
			GRN_LED = LED_ON;		// green LED ON - temp falling

		last_temp_value = current_temp_value;	// prepare for next reading/comparison
	}
}