;
; B3C-DD.INS - Clock routine for the Digital Dynamics card 08/22/85
; -- by pst
;
; This insert should read the clock from a Digital Dynamics
; SpeedPro5 clock card. The SpeedPro5 uses a 5832 chip.
;
; This clock routine needs:
; BCD2BIN - no
; BIN2BCD - no
;
; This routine NEEDS a Z80 processor to function properly.
; It will NOT work with an 8080 or 8085.
;
;----------------------------------------------------------------
;
; Note- This is an insert--not an overlay
;
IF RTC
DDBASE EQU 156 ; Base port of PIO
ADATA EQU DDBASE ; Data port A
ACTRL EQU DDBASE+1 ; Control port A
BDATA EQU DDBASE+2 ; Data port B
BCTRL EQU DDBASE+3 ; Control port B
;
NCS EQU 00000001B ; Not chip select
CLKRD EQU 00000010B ; Clock read
CLKWR EQU 00000100B ; Clock write
ADWWR EQU 00001000B ; Address write
CLKHD EQU 00010000B ; Clock hold
;
TIME: LXI B,ACTRL ; Output mode - port A (reg B=0, C=port)
CALL SETMODE
;
LXI B,BCTRL ; Output mode - port B (reg B=0, C=port)
CALL SETMODE
;
XRA A
OUT ADATA ; Zero address/data lines
MVI A,NCS+CLKHD
OUT BDATA ; Deselect chip
;
LXI H,RTCBUF ; Point to RTC buffer
MVI D,5 ; Set counter for hour tens
CALL RDIGIT ; Get hour tens
CALL SHFT4 ; Save in buffer
CALL MULT10 ; Multiply by 10
STA CCHOUR ; Save temporarily
CALL RDIGIT ; Get hour units in A reg
CALL ADDLOW ; Set BCD digit
MOV B,A
LDA CCHOUR
ADD B ; Add ones digit from B
STA CCHOUR ; Store for later use
;
; Minutes
;
CALL RDIGIT ; Get minute tens in A reg
CALL SHFT4 ; Save in buffer
CALL MULT10 ; Multiply by 10
STA CCMIN ; Save in CCMIN
CALL RDIGIT ; Get minute units in A reg
CALL ADDLOW ; Set BCD digit
MOV B,A
LDA CCMIN
ADD B ; Add in minutes ones from B
STA CCMIN ; Store for later use
;
; Seconds
;
CALL RDIGIT ; Second tens
CALL SHFT4
CALL RDIGIT ; Second units
CALL ADDLOW
;
; Year
;
INX H ; Skip over "19"
MVI D,12 ; Start with years tens
CALL RDIGIT
CALL SHFT4
CALL RDIGIT ; Years units
CALL ADDLOW
;
CALL RDIGIT ; Month tens
CALL SHFT4
CALL RDIGIT ; Month units
CALL ADDLOW
;
CALL RDIGIT ; Day tens
CALL SHFT4
CALL RDIGIT ; Day units
CALL ADDLOW
;
MVI A,0 ; Turn off hold
OUT BDATA
MVI A,NCS ; Deselect chip
OUT BDATA
RET
;
; Read a digit
; Command in D
; Digit returned in A
; D is decremented
; Hold bit is set
; Destroys: 'BCE'
;
RDIGIT: LXI B,ACTRL ; Output mode - port A (b=0, c=port)
CALL SETMODE
;
MOV A,D ; Get command byte
OUT ADATA ; Set address on lines
MVI A,CLKHD+ADWWR ; Hold & Write
OUT BDATA
MVI A,CLKHD ; Hold
OUT BDATA
;
LXI B,0FF00H+ACTRL ; Input mode - port A (b=255, c=port)
CALL SETMODE
;
MVI A,CLKHD+CLKRD ; Hold & Read
OUT BDATA
;
MOV A,D ; Check for hour tens digit
DCR D
CPI 5 ; Was it hour tens digit?
;
IN ADATA ; Read the digit
PUSH PSW
MVI A,CLKHD ; Set hold mode
OUT BDATA
POP PSW
RNZ ; No, return
ANI 3 ; Yes, so kill 24 hour bit
RET
;
; Set for input or output mode of port A
; Entry: mode in B -- 255=output, 0=input
; port to send to in C
;
SETMODE:MVI A,207 ; Mode 3, bit I/O
DB 0EDh,079h ; Z80 instruction = OUT (C),A
DB 0EDh,041h ; Z80 instruction = OUT (C),B
MVI A,7 ; Interrupt control
DB 0EDh,079h ; Z80 instruction = OUT (C),A
MVI A,3
DB 0EDh,079h ; Z80 instruction = OUT (C),A
RET
;
; Multiply register A by 10
; Destroys 'E'
;
MULT10: ADD A ; 2x
MOV E,A
ADD A ; 4x
ADD A ; 8x
ADD D ; 10x
RET
;
; Shift A to high nibble
; Stores shifted value in 'M'
; Destroys 'E'
; A is left unchanged
;
SHFT4: MOV E,A
ANI 15 ; Only handle lower 4 bits
RLC ; Shift A over 4 bits
RLC
RLC
RLC
MOV M,A ; Save it while we're at it
MOV A,E
RET
;
; Add in low BCD nibble
; Gets high nibble from M
; Stores new BCD byte in M
; Increments HL
; Destroyes 'E'
;
ADDLOW: MOV E,A
ANI 15 ; Deal with low nibble only
ORA M ; Add in high nibble from tens digit
MOV M,A ; Save new BCD byte in buffer
INX H ; Move on to next location
MOV A,E
RET
ENDIF ; RTC
