;
; B3C-KP4.INS
; 07/15/85 Clock insert for BYE335 and later
; and the KayPro 4-84
;
; Note: This is an insert, not an overlay.
;
; Use the program TIME2.ASM or later, to initialize your clock
; with correct date/time prior to loading BYE.
;
;
CENTURY EQU 019H ; 19h = 19 bcd, reset this every 100 years
CYEAR EQU 085H ; 85h = 85 bcd, reset this every year
RTCA EQU 20H ; Clock address select reg
RTCD EQU 24H ; Clock data register
RTCS EQU 22H ; Clock status register
REGEND EQU 8 ; Ending register count for time loop
;
;
IF RTC
TIME: MVI A,0CFH ; Initial status setup byte
OUT RTCS ; Set pio for mode 3 in/output
MVI A,0E0H ; Low 5 bits output, top 3 input
OUT RTCS ; Set pio in/out bits
MVI A,03H ; Disable interrupts
OUT RTCS ; Do it
MVI A,14H ; Status reg addr
OUT RTCA ; Select it
IN RTCD ; Reset status bit
;
DOREAD: LXI H,LOCBUF ; Point to time save area
MVI B,2 ; Start with seconds
;
BURST: MOV A,B ; A is register we want to read
CPI REGEND ; Gotten all we want?
JNC ROLLCK ; Yes, done getting time
OUT RTCA ; Select that register of clock
IN RTCD ; Read the clock data
MOV M,A ; Save in core
INX H ; Next memory location
INR B ; Next reg addr
JMP BURST ; Go get more data
;
; See if the clock rolled over during the reads.
;
ROLLCK: MVI A,14H ; Status reg addr
OUT RTCA ; Select it
IN RTCD ; Get status
ORA A ; Was clock roll?
JNZ DOREAD ; Yes, go read again
;
; Format the date and time for bye's realtime clock buffer
;
LDA LOCBUF ; BCD seconds
STA RTCBUF+2
LDA LOCBUF+1 ; BCD minutes
STA RTCBUF+1
CALL BCDBIN ; Convert to binary
STA CCMIN ; For bye5
LDA LOCBUF+2 ; BCD hours
STA RTCBUF
CALL BCDBIN ; Convert to binary
STA CCHOUR ; For bye5
LDA LOCBUF+4 ; BCD day of month
STA RTCBUF+6
LDA LOCBUF+5 ; BCD month
STA RTCBUF+5
MVI A,CENTURY
STA RTCBUF+3
MVI A,CYEAR
STA RTCBUF+4
RET ; All done
;
;
LOCBUF: DB 0 ; Seconds
DB 0 ; Minutes
DB 0 ; Hours
DB 0 ; Day of week (not used by us)
DB 0 ; Day of month
DB 0 ; Month of year
ENDIF ;RTC
;
; End of B3C-KP4.
;----------------------------------------------------------------
