'*** NOTE: CIRCUIT DIAGRAM FOR COMMUNICATION CABLE ***
'*** IS AT THE BOTTOM OF THIS FILE                 ***

'use this program to test your communication cable - 
'each time the stamp gets a particular input (the number 100)
'it replies with the next number as it counts up to 400 and
'back down again.

SerInPin PIN 0		'serial IN pin (RXD - at the other end: TXD)
SerOutPin PIN 1		'serial OUT pin (TXD - at the other end: RXD)
SerInData VAR BYTE  	'number to match to incoming data
SerWait CON 50		'ms to wait for input before timing out
N9600 CON 16468		'BS2 baudmode values: 16468/9600, 16416/19200, 16390/38400
					'See SEROUT in the Basic Stamp manual for details.
myCount VAR WORD	'counter
myCount = 0
upCount VAR BIT		'flag to count up or down
upCount = 1
waitCounter VAR BYTE	'counter to print waiting message to debug window
waitCounter = 0

DEBUG CR,"Program starting ...",CR

Main_Loop:

	'if we're not getting any input, print a message every few seconds
	waitCounter = waitCounter + 1
	IF waitCounter >= 200 THEN	
		DEBUG "Waiting for serial input ...",CR
		waitCounter = 0
	ENDIF
	'read serial in, loop if nothing is received by timeout
	SERIN SerInPin,N9600,SerWait,Main_Loop,[SerInData]  
	IF serInData = 100 THEN
		waitCounter = 0
		GOSUB The_Count	'do counting subroutine
		SEROUT SerOutPin,N9600,[DEC myCount,CR] 	  'send current value
		DEBUG DEC myCount,CR			'print to debug window
	ELSE
		DEBUG "Received: ",DEC SerInData,CR 'got something, but not 100
	ENDIF

GOTO Main_Loop

The_Count:

	IF myCount < 400 AND upCount = 1 THEN	'counting up (0 to 400)
		myCount = myCount+1
	ELSEIF myCount > 0 AND upCount = 0 THEN	'counting down (400 to 0)
		myCount = myCount - 1
	ELSEIF myCount = 400 THEN
		upCount = 0			'switch from up to down
		myCount = 399
	ELSEIF myCount = 0 THEN
		upCount = 1			'switch from down to up
		myCount = 1
	ENDIF

RETURN

'SERIAL CABLE DIAGRAM:
'(use 9 pin female D-Sub connector, Radio Shack #2761538)
'
'     +---------SERIAL OUT [PIN 1]
'     | +--22K--SERIAL IN  [PIN 0]
'     | |   +---GND
'     | |   |
'   1 2 3 4 5
' \-----------/
'  \o o o o o/
'   \o o o o/
'    \-----/
'    6 7 8 9
'
'diagram represents back of connector, facing solder terminals.
'
'