RTC - Revision history

Phi2x: /* RTC Registers */

2025-04-04T15:33:18Z

‎RTC Registers

Phi2x: /* RTC Registers */

2025-04-04T15:31:34Z

‎RTC Registers

Phi2x: /* RTC Registers */

2025-04-04T15:29:30Z

‎RTC Registers

Phi2x: /* RTC Registers */

2025-04-04T14:51:58Z

‎RTC Registers

Phi2x: /* RTC Registers */

2025-04-03T15:02:22Z

‎RTC Registers

Deprecated: The each() function is deprecated. This message will be suppressed on further calls in /mnt/cpcwiki-httpdocs/includes/diff/DairikiDiff.php on line 434

Phi2x: /* PC compatible RTC chip */

2025-04-03T10:45:15Z

‎PC compatible RTC chip

Phi2x: /* PC compatible RTC chip */

2025-04-03T10:43:56Z

‎PC compatible RTC chip

Phi2x: /* Usage in CPCs */

2025-04-03T10:22:08Z

‎Usage in CPCs

Phi2x: /* PC compatible RTC chip */

2025-04-03T10:17:52Z

‎PC compatible RTC chip

Phi2x: /* PC compatible RTC chip */

2025-04-03T10:13:29Z

‎PC compatible RTC chip

@@ Line 97: / Line 97: @@
 | 08H || 0 || 0 || 0 || 0 || colspan="4" | Month || Month || 01–0C
 |-
-| 09H || colspan="8" | Year || Year || 00–63
+| 09H || 0 || colspan="7" | Year || Year || 00–63
 |}

@@ Line 38: / Line 38: @@
 {| class="wikitable" style="text-align:center;"
 |-
-! rowspan="2" | Register !! colspan="8" | Bit Position !! rowspan="2" | Function !! rowspan="2" | Range (BCD)
+! rowspan="2" | Register !! colspan="8" | Bit Position !! rowspan="2" | Function !! rowspan="2" | Range
 |-
 ! 7 || 6 || 5 || 4 || 3 || 2 || 1 || 0
@@ Line 71: / Line 71: @@
 {| class="wikitable" style="text-align:center;"
 |-
-! rowspan="2" | Register !! colspan="8" | Bit Position !! rowspan="2" | Function !! rowspan="2" | Range (BCD)
+! rowspan="2" | Register !! colspan="8" | Bit Position !! rowspan="2" | Function !! rowspan="2" | Range
 |-
 ! 7 || 6 || 5 || 4 || 3 || 2 || 1 || 0

@@ Line 38: / Line 38: @@
 {| class="wikitable" style="text-align:center;"
 |-
-! ADDRESS !! BIT 7 !! BIT 6 !! BIT 5 !! BIT 4 !! BIT 3 !! BIT 2 !! BIT 1 !! BIT 0 !! FUNCTION !! RANGE
+! rowspan="2" | Register !! colspan="8" | Bit Position !! rowspan="2" | Function !! rowspan="2" | Range (BCD)
 |-
 | 00H || 0 || colspan="3" | 10 Seconds || colspan="4" | Seconds || Seconds || 00–59
@@ Line 69: / Line 71: @@
 {| class="wikitable" style="text-align:center;"
 |-
-! ADDRESS !! BIT 7 !! BIT 6 !! BIT 5 !! BIT 4 !! BIT 3 !! BIT 2 !! BIT 1 !! BIT 0 !! FUNCTION !! RANGE
+! rowspan="2" | Register !! colspan="8" | Bit Position !! rowspan="2" | Function !! rowspan="2" | Range (BCD)
 |-
 | 00H || 0 || 0 || colspan="6" | Seconds || Seconds || 00–3B

@@ Line 48: / Line 48: @@
 | 03H || 0 || colspan="3" | 10 Minutes || colspan="4" | Minutes || Minutes Alarm || 00–59
 |-
-| 04H || AM/PM || 0 || 0 || 10 Hours || colspan="4" | Hours || Hours || 1–12 +AM/PM<br>00–23
+| rowspan="2" | 04H || AM/PM || rowspan="2" | 0 || 0 || 10 Hours || colspan="4" | Hours || rowspan="2" | Hours || 1–12 +AM/PM
 |-
-| 05H || AM/PM || 0 || 0 || 10 Hours || colspan="4" | Hours || Hours Alarm || 1–12 +AM/PM<br>00–23
+| 0 || colspan="2" | 10 Hours || colspan="4" | Hours || 00–23
 |-
 | 06H || 0 || 0 || 0 || 0 || 0 || colspan="3" | Day || Day || 01–07
@@ Line 75: / Line 79: @@
 | 03H || 0 || 0 || colspan="6" | Minutes || Minutes Alarm || 00–3B
 |-
-| rowspan="2" | 04H || AM/PM || rowspan="2" | 0 || rowspan="2" | 0 || 0 || colspan="4" | Hours || rowspan="2" | Hours || rowspan="2" | 01–0C +AM/PM<br>00–17
+| rowspan="2" | 04H || AM/PM || rowspan="2" | 0 || rowspan="2" | 0 || 0 || colspan="4" | Hours || rowspan="2" | Hours || 01–0C +AM/PM
 |-
-| 0 || colspan="5" | Hours
+| 0 || colspan="5" | Hours || 00–17
 |-
-| rowspan="2" | 05H || AM/PM || rowspan="2" | 0 || rowspan="2" | 0 || 0 || colspan="4" | Hours || rowspan="2" | Hours Alarm || rowspan="2" | 01–0C +AM/PM<br>00–17
+| rowspan="2" | 05H || AM/PM || rowspan="2" | 0 || rowspan="2" | 0 || 0 || colspan="4" | Hours || rowspan="2" | Hours Alarm || 01–0C +AM/PM
 |-
-| 0 || colspan="5" | Hours
+| 0 || colspan="5" | Hours || 00–17
 |-
 | 06H || 0 || 0 || 0 || 0 || 0 || colspan="3" | Day || Day || 01–07

@@ Line 34: / Line 34: @@
 === RTC Registers ===
-h  Second       (00..59) ;\
+Registers 00H-09H in BCD mode:
-h  Alarm second (00..59) ; these ten registers can be BCD or Binary
-h  Minute       (00..59) ; (see Control B, Bit2=DM)
+{| class="wikitable" style="text-align:center;"
-h  Alarm minute (00..59) ;
+|-
-h  Hour         (00..23) ;  ;\in 24hour mode:
+! ADDRESS !! BIT 7 !! BIT 6 !! BIT 5 !! BIT 4 !! BIT 3 !! BIT 2 !! BIT 1 !! BIT 0 !! FUNCTION !! RANGE
-h  Alarm hour   (00..23) ;  ;/bit7=PM
+|-
-h  Day of week  (01..07) ;
+| 00H || 0 || colspan="3" | 10 Seconds || colspan="4" | Seconds || Seconds || 00–59
-h  Day          (01..31) ;
+|-
-h  Month        (01..12) ;
+| 01H || 0 || colspan="3" | 10 Seconds || colspan="4" | Seconds || Seconds Alarm || 00–59
-h  Year         (00..99) ;/
+|-
 Ah  Control A
    UIP Update in Progress (0=Stable in next 244us, 1=Time changes) (R)
@@ Line 66: / Line 115: @@
    VRT  Valid RAM and Time (1=Okay, 0=Battery Low)              (R)
 -0 0    Reserved (zero)
 Eh..3Fh battery backed RAM (HD146818, DS1287A, DS12887A and other chips)
 h..7Fh battery backed RAM (only on DS12887A and newer chip variants)
 == Other chips ==

@@ Line 23: / Line 23: @@
 Usage in [[Aleste 520EX - I/O Ports]]:
-   Uses a russian KR512WI1 chip (which is, according to the Aleste's
+   Uses a russian KR512WI1 chip (which is, according to the Aleste's Manual) compatible to western MC146818 chips.
-  Manual) compatible to western MC146818 chips.
    Connects to a 32.768kHz crystal.
    Connects to the PPI:
@@ Line 31: / Line 30: @@
      PPI Port C.Bit1   = Index Access (0=No, 1=Access)
      PPI Port C.Bit2   = Data Access  (0=No, 1=Access)
-   In the Aleste's Ext Port, the RTC must be enabled, and PSG and
+   In the Aleste's Ext Port, the RTC must be enabled, and PSG and 8253 must be disabled.
-must be disabled.
 === RTC Registers ===

@@ Line 17: / Line 17: @@
    FBE2h  Dk'tronics Real Time Clock - Z80 PIO Port A Control
    FBE3h  Dk'tronics Real Time Clock - Z80 PIO Port B Control
-   FBE8h  Dk'tronics Real Time Clock - Control port for RTC chip (4bit latch) (details unknown)
+   FBE8h  Dk'tronics Real Time Clock - Control port for RTC chip (4bit latch) '''(details unknown)'''
    Port B is connected directly to a standard 9-way connector on the left of the interface.

@@ Line 12: / Line 12: @@
 Usage in [[Dk'tronics Real Time Clock]]:
-   Uses a HD146818 chip.
+   Uses a Z80 PIO chip to control the HD146818 RTC chip via port A. Do not use Port A as this will affect the RTC operation.
    FBE0h  Dk'tronics Real Time Clock - Z80 PIO Port A Data (HD146818P RTC Data bus)
    FBE1h  Dk'tronics Real Time Clock - Z80 PIO Port B Data, used for external control (General Purpose 8bit I/O Port)
@@ Line 18: / Line 18: @@
    FBE3h  Dk'tronics Real Time Clock - Z80 PIO Port B Control
    FBE8h  Dk'tronics Real Time Clock - Control port for RTC chip (4bit latch) (details unknown)
-   Do not use Port A as this will affect the RTC operation.
+   Port B is connected directly to a standard 9-way connector on the left of the interface.
 ----