'
' Nixie Clock using Model 01 rev. B CPU/IO card and Nixie daughterboard.
' Will display YY/MM/DD or HH:MM:SS on the six Nixie displays. 
' Various global modes (eg. 12/24 hour display; date order) are
' determined by power-up switch settings and remembered in EEPROM.
' AM/PM and blinking colon are supported on revision A board.
'
' mru 19 Apr 1999
' Clear colon and PM when displaying date. Increased speed of
' BUTTON delays.
'
' mru 14 Apr 1999
' Fixed handling of zero'd seconds when in SET mode.
' Date display doesn't seem to go crazy any more (cause?!)
' Made 24 hr. mode change date display to DD MM YY.
' Added AM/PM support (requires rev. A)
' Added blinking colon (requires rev. A)
' Determined power on/off clock data damage due to HV interference.
' Improved power on self-test.
'
' Switches: all are ground-asserted, with pullups on the board.
'
'	RUN/SET			Ground to enter SET mode. Display stops.
'	TIME/DATE		Ground to display (set) date, else time.
'	INC H/M, M/D, Y/S	Ground to increment; hold down for rapid.
'
' POWER-ON MODE SETS:
' Hold indicated switch down when powering up.
'
' HOUR/YEAR:			Toggles 24/12 hour time display; when
'				in 12 hour mode, date displays as
'				MM DD YY; in 24 hr. mode it displays as
'				DD MM YY.
'
' SEC/DAY:			Toggles blink/no blink of colon. 
'
'
' Tom Jennings
' written 17 July 98
'
' Copyright Tom Jennings, 1999.
'

' BUGS: 
'
' 29 July 98: still seems to be a problem wrecking RTC settings on
' power up or down. Works much better when RC filter installed on PA4.
'

symbol	BDELAY= 30			' loop delay til autorepeat (button())
symbol	BREPT= 4			' loop delay between autorepeat
symbol	LPAUSE= 40			' loop delay, mS

' e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e 
'
' Bit flags are all in B0, which is stored in EEPROM, and reloaded
' on power up. Some values are global, eg. 12/24 hour display mode. Some
' are local, eg. TIME/DATE switch pressed. The colon and AM/PM indicators
' states are stored here as well. Most flags are bit-position-dependent, 
' used for programming convenience.
'
symbol	flags= b0			' reserved for bit flags
'
'	flags	dmode	tmode
'	0=	0	0		time, 12hr mode, HH MM SS
'	1=	0	1		time, 24hr mode, HH MM SS
'	2=	1	0 		date, MM DD YY
'	3=	1	1 		date, DD MM YY
'
symbol	DISPBITS= 3			' mask display mode bits
symbol	tmode= bit0			' (0..1) GLOBAL 1 == 24 hour mode
symbol	dmode= bit1			' (0..1) LOCAL  1 == display date else time
'
symbol	cblink= bit2			' (0..1) LOCAL 1 == disable colon blink
'
'colon, pm must be MS, 2nd MS bits; they're ORed into SRA output directly.
symbol	HWBITS= 192			' mask hardware bits
symbol	pm= bit6			' (0..1) LOCAL PM else AM
symbol	colon= bit7			' (0..1) LOCAL 1 == colons lit
'
' e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e 

symbol	unused1= b1

symbol	i= b2
symbol	n= b3
symbol	k= b4
symbol	j= b5
symbol	l= b6

symbol	bvar1= b12			' temp for button command
symbol	bvar2= b13			' temp for button command
symbol	bvar3= b14			' temp for button command
'
' Time & date data as used by the RTC routines. See the getclock() and setclock()
' code for data handling details (eg. packing/unpacking of BCD for the compiler
' RTC routines). These always contain the last-read RTC values.
'
symbol	year= b15
symbol	month= b16
symbol	day= b17
symbol	daywk= b18
symbol	hour= b19
symbol	minute= b20
symbol	second= b21

'
' Pin assignments (eg. 3 = pin3). Very annoying that the compiler doesn't 
' syntactically allow 'pin 3' or 'pin SD'. Inputs are pulled up, and are 
' logically ON when pulled to ground.
'
'symbol	SW_SET= SET switch is on PA4		' (0..1) 0 == RUN/SET in SET position
symbol	SW_DATE= pin7				' (0..1) 0 == TIME/DATE in DATE position
symbol	SW_HY= pin6				' (0..1) 0 == INCREMENT HOUR(YEAR) switch pressed
symbol	BIT_HY= 6				' number of the HOUR(YEAR) pin (aargh)
symbol	SW_MM= pin5				' (0..1) 0 == INCREMENT MINS(MONTH) switch pressed
symbol	BIT_MM= 5				' number of the MIN(MONTH) pin
symbol	SW_SD= pin4				' (0..1) 0 == INCREMENT SEC(DAY) switch pressed
symbol	BIT_SD= 4				' number of the SEC(DAY) pin

'
' Data is written to the shift registers by asserting data on the SD pin, and clocking
' the appropriate SR clock pin. 8 bits per shift register, MS bit output first.
'
symbol	SDpin= 	pin0				' pin number, Serial Data to shift reg
symbol	SD=	0				' Serial Data pin number
symbol	SRC=	3				' SR C clock (SS, YY)
symbol	SRB=	2				' SR B clock (MM, DD)
symbol	SRA=	1				' SR A clock (HH, MO)

'
' Startup code starts here. - - - - - - - - - - - - - - - - - - - - - - - - - 
'
main:	pause 1000				' let power settle, preserve RTC!

	dirs= %00001111				' MS bits inputs, rest outputs.
	pins= 0					' deassert device selects
	peek 133, n : n= n | 16 : poke 5, n	' make PA4 an input

	year= 55 : month= 7 : day= 31		' my birthday! (in case DATE pressed)
	flags= 1				' force 24 hr, colon blink modes,
	hour= 0
	for i= 0 to 99 step 11			' test Nixies,
		minute= i : second= minute
		gosub display
		pause 150
	next i
	for hour= 0 to 23
		pm= hour / 12			' test PM too,
		gosub display
		pause 100
	next hour
	pause 700

'
' Load global settings from EEPROM; if certain switches are pressed at power up, 
' change global settings.
'
	read 0, flags				' read global settings from EEPROM

	if SW_HY = 1 then pu1			' if INCR HOUR(YEAR) pressed,
	tmode= tmode + 1			' toggle 12/24 hour mode,
	write 0, flags				' update EEPROM

pu1:	if SW_SD = 1 then pu2			' if SECOND(DAY) pressed,
	cblink= cblink + 1			' toggle colon blink,
	write 0, flags

pu2:
puz:

' End of startup, beginning of runtime. - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
'
' The main loop here is the basic clock function. TIME/DATE determines which three
' bytes are displayed. RUN/SWITCH must be in the SET switch for a long time before
' we enter SET mode; this not only debounces the switch, it prevents spurious writes
' on power down where the switch pullups go down before CPU power.
'
a1:	gosub getclock				' read RTC data, unpack and copy,
	gosub display				' display current values,
	pause 200				' don't hit RTC too often
	gosub setsw				' check SET switch,
	if n <> 0 then a1			' loop if not.

	pause 200				' long delay if SET detected
	bvar1= 0 : bvar2= 0 : bvar3= 0		' clear SET function switch vars

'
' Check to see if SET is pressed; this is a big debounce for the first time
' through the loop, and the loop terminator.
'
a2:	gosub setsw
	if n <> 0 then a1			' branch if SET switch not pressed.
	gosub display				' display new or current values,

'
' Set mode is pretty simple; pressing HOUR(YEAR), MINUTE(MONTH)
' or SECOND(DAY) increments the time/date field; "SECONDS" clears seconds
' to 0. NOTE: any clock set function sets seconds to zero!
'
	button BIT_HY, 0, BDELAY, BREPT, bvar1, 0, m2 ' if INCREMENT HR/YEAR pressed,
	if dmode = 0 then m1a			' and DATE mode,
	year= year + 1 // 100 : goto mw		' increment YEAR (0..99)
m1a:	hour= hour + 1 // 24 : goto mw		' else increment HOUR (0 - 23)

m2:	button BIT_MM, 0, BDELAY, BREPT, bvar2, 0, m3 ' if INCREMENT MIN/MON pressed,
	if dmode = 0 then m2a
	month= month // 12 + 1 : goto mw	' increment MONTH (1..12)
m2a:	minute= minute + 1 // 60 : goto mw	' increment MINUTE (0..59)

m3:	button BIT_SD, 0, BDELAY, BREPT, bvar3, 0, mw ' if INCREMENT SEC/DAY pressed,
	if dmode = 0 then mw			' increment DAY (1..N)
	lookup month, (0,31,28,31,30,31,30,31,31,30,31,30,31), n ' find N
	i= year // 4 + n 			' will be 28 iff leap year and Feb.
	if i > 28 then m3a
	n= 29
m3a:	day= day // n + 1

mw:	second= 0				' make display reflect reality,
	gosub setclock				' write new time or date,
mz:	pause LPAUSE				' make loop execute time more uniform,
	goto a2					' repeat; we're just a stupid clock.

'
' Return 0 in N if SET switch is pressed.
'
setsw:	peek 5, n : n= n & 16 : return


'
' Write time or date to the six Nixie displays. 
' Uses J, K, modifies flags.
'
display:
	dmode= SW_DATE + 1			' read TIME/DATE switch,
	k= hour					' preload for time display,
	colon= 0 : pm= 0			' leave clear for date display
	j= flags & DISPBITS			' clear display mode bits,
	branch j, (d0, d1, d2, d3)		' see 'flags' comment.

' 12hr. time, AM, PM.
'                  ---------- AM -------------   ------------- PM (+128) -----------------------
d0:	k= hour / 12 : pm= k			' PM on when hour > 12
	lookup hour, (12,1,2,3,4,5,6,7,8,9,10,11,   12,1,2,3,4,5,6,7,8,9,10,11), k

' 12 or 24 hr. time (AM/PM pre-set, above).
d1:	colon= second + 1 | cblink		' colons ON on even seconds,
	            gosub toBCD : call outA	' HH
	k= minute : gosub toBCD : call outB	' MM
	k= second : gosub toBCD : call outC	' SS
	return

' Date, MM DD YY.
d2:	k= month : gosub toBCD : call outA	' MM
	k= day   : gosub toBCD : call outB	' DD
	k= year  : gosub toBCD : call outC	' YY
	return

' Date, DD MM YY.
d3:	k= day   : gosub toBCD : call outA	' DD
	k= month : gosub toBCD : call outB	' MM
	k= year  : gosub toBCD : call outC	' YY
dz:	return

'
' Convert canonical value in K (0 - 99 max) to packed BCD.
'
toBCD: j= k // 10 : k= k / 10 * 16 + j : return


'
' These two routines use an ugly peek/poke hack for compactness and speed. They
' originally came from MicroMint documentation; the numeric offsets are magic.
'
' Both use private variables J, K, L.
'
' Read the RTC, convert packed BCD to canonical, and copy HHMMSS or YYMMDD
' into the working data, as specified by the TIME/DATE switch.
'
getclock:
	call clockget				' read the RTC
gc1:	for j= 27 to 33				' Bxx register number
		peek j, k			' read packed-hex
		l= k / 16 * 10 : k= k & $0f : k= k + l
		poke j, k
	next j
	return

'
' Convert canonical time & date to packed BCD; write to the RTC;
' convert back to canonical. (Leaves the data consistently usable
' to other routines at little processing cost).
'
setclock: 
	for j= 27 to 33				' Bxx register number
		peek j, k			' read packed-hex
		l= k / 10 * 16 : k= k // 10 : k= k + l
		poke j, k
	next j
	call clockset				' write to RTC,
	goto gc1				' unpack again


END 'BASIC


	asm

;
; Output all 8 bits of K, and the colon and PM bit, to SR A. Modifies J, K.
;
_outA	movlw 8
	movwf _J				; set bit counter,

	movf _FLAGS, w				; get colon, AM/PM bits,
	andlw _HWBITS				; strip clean,
	iorwf _K, f				; OR in BCD bits,

_oa1	bcf portB, _SD				; set data bit= 0
	rlf _K, f				; move MSB to carry,
	btfsc status, 0				; if carry set (MSB == 1)
	bsf portB, _SD				; assert a 1,
	bsf portB, _SRA				; clock data bit out,
	bcf portB, _SRA	
	decfsz _J, f				; repeat.
	goto _oa1
	goto done

;
; Output all 8 bits of K to SR B. Modifies J, K.
;
_outB	movlw 8
	movwf _J				; set bit counter,

_ob1	bcf portB, _SD				; set data bit= 0
	rlf _K, f				; move MSB to carry,
	btfsc status, 0				; if carry set (MSB == 1)
	bsf portB, _SD				; assert a 1,
	bsf portB, _SRB				; clock data bit out,
	bcf portB, _SRB	
	decfsz _J, f				; repeat.
	goto _ob1
	goto done

;
; Output all 8 bits of K to SR C. Modifies J, K.
;
_outC	movlw 8
	movwf _J				; set bit counter,

_oc1	bcf portB, _SD				; set data bit= 0
	rlf _K, f				; move MSB to carry,
	btfsc status, 0				; if carry set (MSB == 1)
	bsf portB, _SD				; assert a 1,
	bsf portB, _SRC				; clock data bit out,
	bcf portB, _SRC	
	decfsz _J, f				; repeat.
	goto _oc1
	goto done


	endasm