rem NixieClock.bas 3/23/2008
rem The two dials are for setting the time to the next five minute
rem To set, put the switch to the left for AM, else right, and push the button
rem After it reaches the set time, put the switch to the right immediately to hold
rem set the switch to the middle when the five-minute point is reached.
rem uses 127 bytes out of 128

#picaxe 18

rem Input ports
symbol Duration	= 1			'No space to implement
symbol RTC		= Input2
symbol Wipers	= Input7
symbol SRData	= Input6

rem Output ports
symbol SRCLK	= 0			'For inputs except analog duration and wipers
symbol SRLoad	= 1			'For inputs except analog duration and wipers
symbol Relay	= 2			'No space to implement
symbol DimAMLED	= 3
symbol TestPoint	= 5			'Used to set the oscillator
symbol BrtAMLED	= 6			'No space to implement, dim is bright enough
symbol NixieCLK	= 7			'Advances on negative edge, which is HIGH

rem global variables
symbol Phase	= bit0		'Of the 2 hz square wave
symbol Cycles	= b1			'Of the half-cycles
symbol Mask		= b2			'For shift register values
symbol BitPos	= b3			'Shift register iterator
symbol Control	= b4			'Control and status inputs
symbol Old12Hrs	= b5			'Both inputs high betwen 12:00 and 12:59
symbol New12Hrs	= b6			'Both inputs high betwen 12:00 and 12:59
symbol SetMode	= b7			'After button is pressed until set time is reached
symbol AM		= b8			'Non-zero for AM
symbol Hold		= b9			'Non-zero for hold

rem constants to isolate particular inputs
symbol RunMask	= %00000001		'QH
symbol SetMask	= %00000010		'QG
symbol AMMask	= %00000100		'QF
symbol HoldMask	= %00001000		'QE
symbol PotMask	= %01000000		'QB - No space to implement
symbol HrsMask	= %10100000		'QA & QC

rem EEPROM data
DATA 0,(1,2,4,8,16,32,64,128)		'Mask of bits for Shifting

init:
 

main:
ReadControl:				'shifts 8 bits  QH first low voltage gives a one
HIGH SRCLK					
LOW SRLoad					'Loads on low volts - pulse high because of darlington
PULSOUT SRLoad,1				'Load the control data into the '165
LET Control = 0
FOR BitPos = 0 TO 7			
	IF SRData = 1 THEN NotOn	'Invert sense because switches go to common
		READ BitPos,Mask
		LET Control = Control | Mask
NotOn:
	PULSOUT SRCLK,1
NEXT

rem Turn the AM LED on or off
IF AM = 0 THEN				
	LOW DimAMLED			'LED off
ELSE
	HIGH DimAMLED			'LED on
ENDIF

rem Set the time
IF SetMode = SetMask THEN InSetMode	'Button has been pressed
LET SetMode = Control & SetMask	'See if the set button is pressed

InSetMode:					'Continue once in set mode
IF Wipers = 1 OR SetMode = 0 THEN NotSetting 'reached the time setting, 
LET Cycles = 0				'First advance is one minute after time is reached
PULSOUT NixieCLK, 100			'Count up until the set time is reached
LET AM = Control & AMMask		'Set the AM during setting only
GOTO main


NotSetting:
LET SetMode = 0				'go to normal operation

rem wait for end of RTC half-cycle - 250 milliseconds
IF Phase = RTC THEN main
LET Phase = RTC

rem quarter-second processing
LET Hold = Control & HoldMask		'Hold updating until the next 5-min time is reached
IF Hold = HoldMask THEN main
INC Cycles

rem one minute processing
IF  Cycles > 239 THEN			'Clock the counter and determine AM or PM
	LET Cycles = 0
	HIGH NixieCLK			'Clocks on going high, low volts after darlington
	LET New12Hrs = Control & HrsMask  
	IF New12Hrs <> Old12Hrs AND New12Hrs = 0 THEN 'Got to 12:01	
		LET AM = AM ^ AMMask
	ENDIF
	LET Old12Hrs = New12Hrs
ELSEIF Cycles <> 40 THEN		'The nixie counter prefers a squareish wave
	LOW NixieCLK 
ENDIF
GOTO main
END