Hi,

I am thinking about controller for hydroponic greenhouse, so I need
real time clock.
I am looking thru several examples that I can find on web, and have
found this code:
http://www.bobblick.com/techref/projects/propclock/mclock8.asm

Question is - why the original author is swapping nibbles, when saving
STATUS byte, in interrupt routine? It is reswapped back again, when
restoring.

;--------
; INTERRUPT SERVICE ROUTINE
;--------
		org	0x04		;interrupt vector
Intsvc		movwf	safe_w		;save w
		swapf	STATUS,w	;swap status, w
		movwf	safe_s		;save status(nibble swap, remember)
;--------
; done saving, now start working
;--------

<blablabla>

;--------
; done working, start restoring
;--------
		swapf	safe_s,w	;fetch status, reswap nibbles
		movwf	STATUS		;restore status
		swapf	safe_w,f	;swap nibbles in preparation
		swapf	safe_w,w	;for the swap restoration of w
		bcf	INTCON,2	;clear interrupt flag before return
		retfie			;return from interrupt




Anybody knows some good (well commented :) real time clock sources to look thru?

-- 
KPL
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