Balloon Monitor Pseudocode

define ports
define registers:
	Q_temp
	BYTE_COUNT
	W_TEMP
	STATUS_TEMP
	LAST_RX
	AA
	BB
	CC
	DD
	EE
	CK

Main:

Clear ANSEL
Clear ANSELH
Set debugging ports as outputs
Set QueryPin as output
Set RX pin as input

Set up UART
	disable sync
	set up baud rate for 9600
	enable serial module
	enable receiver (don't need transmitter)
	enable receive complete interrupt

Set up Timer1
	Set prescale for timer 1 to 8
	Set up CCP1CON so in compare mode, generate a software interrupt, and 		toggles CCP1 pin upon match.
	enable CCP1 interrupt
	put 31250 into CCPR1 register initially
	turn Timer1 on, use Fosc/4 (5Mhz) 
	Set Q_temp high

EnableInterrupts

LoopForever, responding to Interrupts as follows


Interrupt responses 
	Save working and status registers
	Check for RX interrupt (RCIF flag)
		go to RxInterrupt if there is	
	Check for Timer1 OC interrupt (CCP1F) 
		go to Tmr1Interrupt

ISRcomplete:
	Restore status register
	Restore working register
	Return to file, enable global interrupts

Tmr1Interrupt
	Clear CCP1IF interrupt flag
 	If Q_temp is 1, 
		put 31250 into CCPR1 registers  (50 ms)
		set Q_temp to 0
		goto ISRcomplete
	else 
		put 2500 into CCPR1 registers     (4ms) 
		set Q_temp to 1
		goto ISR complete

RxInterrupt
	load newest receive byte, clearing the RCIF flag
	If there's a framing error
		go to RxError
	If there's a receiver overrun error
		go to RxError
	Save received byte in working register to LAST_RX
	
	If LAST_RX == 0x02	
		Set BYTE_COUNT to 1
		go to ISR complete
	else (NotFirstByte)
		If BYTE_COUNT = 1
			Store LAST_RX as AA
			Set BYTE_COUNT to 2
			goto ISRcomplete
		else If BYTE_COUNT = 2
			Store LAST_RX as BB
			Set BYTE_COUNT to 3
			goto ISRcomplete
		else If BYTE_COUNT = 3
			Store LAST_RX as CC
			Set BYTE_COUNT to 4
			goto ISRcomplete
		else If BYTE_COUNT = 4
			Store LAST_RX as DD
			Set BYTE_COUNT to 5
			goto ISRcomplete
		else If BYTE_COUNT = 5
			Store LAST_RX as EE
			Set BYTE_COUNT to 6
			goto ISRcomplete
		else If BYTE_COUNT = 6
			Store LAST_RX as CK
			Set BYTE_COUNT to 7
			goto ISRcomplete
		else If BYTE_COUNT = 7
			if LAST_RX not equal to 0x03
				go to ByteFailed
			else
				Set BYTE_COUNT to 0
				Check checksum
				if resulting XOR is not 0
					go to ByteFailed
				else (correct checksum)
					clear LEDs
					if CK = 0x5f
						balloon is Intact
						light green LED
						go to ISRcomplete
					else 
						balloon is popped 
						light red LED 
						go to ISRcomplete			
		else go to ByteFailed

RxError:
	Light yellow LED
	go to ISRcomplete
ByteFailed:
	Light yellow LED
	go to ISRcomplete