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Cleanup of DS12RTC Driver

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- Offset NVRAM register access by $60 to avoid collisions with IBM PC CMOS usage.
- Wrap register accesses in DI/EI.  The DS1288x requires no interrupts between the register selection and the data r/w.
- Minor comment improvements.
This commit is contained in:
Wayne Warthen
2025-11-26 13:05:21 -08:00
parent 8c7f51fd74
commit ac48639bfc
1 changed files with 20 additions and 11 deletions
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31
Source/HBIOS/ds12rtc.asm
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@@ -43,6 +43,11 @@
; | $0D | VRT | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
; +-----+-------+-------+-------+-------+-------+-------+-------+-------+
;
; NOTE: THE IBM PC CMOS USES REGISTER ADDRESSES UP TO $5F. THIS RTC
; IS SOMETIMES USED IN SYSTEMS THAT HAVE A X86 BOARD, SO WE AVOID ANY
; CONFLICT BY OFFSETTING OUR REGISTER INDEXES BY $60. THIS MEANS WE
; MAP REQUESTS FOR $00-$1F TO NVRAM REGISTERS $60-$7F.
;
DS12RTC_IO .EQU $70
DS12RTC_SEL .EQU DS12RTC_IO + 0
DS12RTC_DATA .EQU DS12RTC_IO + 1
@@ -197,7 +202,7 @@ DS12RTC_SETTIM:
;
DS12RTC_GETBYT:
LD A,C ; INDEX TO ACCUM
ADD A,$0E ; RAM STARTS AT INDEX $0E
ADD A,$60 ; WE USE NVRAM STARTING AT $60
LD C,A ; INDEX BACK TO C
CALL DS12RTC_RDREG ; GET THE VALUE
LD E,A ; PUT IN E TO RETURN
@@ -210,7 +215,7 @@ DS12RTC_GETBYT:
;
DS12RTC_SETBYT:
LD A,C ; INDEX TO ACCUM
ADD A,$0E ; RAM STARTS AT INDEX $0E
ADD A,$60 ; WE USE NVRAM STARTING AT $60
LD C,A ; INDEX BACK TO C
LD A,E ; PUT VALUE IN A
CALL DS12RTC_WRREG ; WRITE IT
@@ -283,25 +288,25 @@ DS12RTC_WRCLK:
LD E,L ; ... IN CASE OF RESTART
LD C,$09 ; START WITH YEAR REG
CALL DS12RTC_WRCLK1 ; DO YEAR (REG $09)
JR NZ,DS12RTC_WRCLK ; RESTART IF SO
JR NZ,DS12RTC_WRCLK ; RESTART IF UIP DETECTED
CALL DS12RTC_WRCLK1 ; DO MONTH (REG $08)
JR NZ,DS12RTC_WRCLK ; RESTART IF SO
JR NZ,DS12RTC_WRCLK ; RESTART IF UIP DETECTED
CALL DS12RTC_WRCLK1 ; DO DAY OF MONTH (REG $07)
JR NZ,DS12RTC_WRCLK ; RESTART IF SO
JR NZ,DS12RTC_WRCLK ; RESTART IF UIP DETECTED
DEC C ; SKIP DAY OF WEEK (REG $06)
DEC C ; SKIP HOURS ALARM (REG $05)
CALL DS12RTC_WRCLK1 ; DO HOUR (REG $04)
JR NZ,DS12RTC_WRCLK ; RESTART IF SO
JR NZ,DS12RTC_WRCLK ; RESTART IF UIP DETECTED
DEC C ; SKIP MINUTES ALARM (REG $03)
CALL DS12RTC_WRCLK1 ; DO MINUTES (REG $02)
JR NZ,DS12RTC_WRCLK ; RESTART IF SO
JR NZ,DS12RTC_WRCLK ; RESTART IF UIP DETECTED
DEC C ; SKIP SECONDS ALARM (REG $01)
CALL DS12RTC_WRCLK1 ; DO SECONDS (REG $00)
;
XOR A ; SIGNAL SUCCESS
RET ; DONE
;
DS12RTC_WRCLK1: ; 108TS
DS12RTC_WRCLK1:
LD A,(DE) ; GET VALUE
CALL DS12RTC_WRREG ; WRITE IT
INC DE ; BUMP BUF PTR
@@ -339,22 +344,26 @@ DS12RTC_INITDEV:
; C=REGISTER
; A=VALUE
;
DS12RTC_RDREG: ; 43TS
DS12RTC_RDREG:
HB_DI ; NO INTS BETWEEN REG SEL AND DATA
LD A,C ; REGSITER TO A
OUT (DS12RTC_SEL),A ; SELECT IT
IN A,(DS12RTC_DATA) ; GET REG VALUE
HB_EI ; RESTORE INTS
RET ; DONE
;
; WRITE REGSITER
; C=REGSITER
; A=VALUE
;
DS12RTC_WRREG: ; 64TS
DS12RTC_WRREG:
HB_DI ; NO INTS BETWEEN REG SEL AND DATA
PUSH AF ; SAVE VALUE TO WRITE
LD A,C ; REGSITER TO A
OUT (DS12RTC_SEL),A ; SELECT IT
POP AF ; RECOVER VALUE TO WRITE
OUT (DS12RTC_DATA),A ; GET REG VALUE
HB_EI ; RESTORE INTS
RET ; DONE
;
; CHECK FOR UPDATE IN PROGRESS
@@ -377,4 +386,4 @@ DS12RTC_UIP:
; DS12RTC_TIMBUF IS DRIVER'S INTERNAL CLOCK DATA BUFFER
;
DS12RTC_TIMBUF .FILL 6,0 ; 6 BYTES FOR GETTIM, YYMMDDHHMMSS
DS12RTC_TIMDEF .DB $00,$01,$01,$00,$00,$00
DS12RTC_TIMDEF .DB $00,$01,$01,$00,$00,$00 ; DEFAULT DATE/TIME