Contains a rechargeable battery, five chips, a quartz crystal, a 8bit general-purpose I/O port (9pin DSUB), and a few odds and ends.The RTC chip is a HD146818 (which is also used in IBM PCs).== Technical ==
== Info Fragment ==Contains following components: HD146818P ([[PC compatible RTC chip|PC-style RTC]]), a TMP[[Z80 PIO|Z84C20]]P ([[Z80 PIO]]), 74LS00 (Quad NAND), 74LS138 (demux), 74LS175 (4bit latch), 9pin male DSUB connector (used as an 8bit general-purpose I/O port), and a rechargeable 3.6V battery.
Reportedly: DK-Tronics RTC module used a Z80-PIO chip to address The battery is charged while the RTC itself as Port A of computer is switched on. The data will be retained for several months even if the PIO, with a 9-pin user i/o port as Port Bcomputer is not used during this time.
== 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 ([[PC compatible RTC chip|HD146818P]] RTC Data bus) FBE1h Dk'tronics Real Time Clock - [[Z80 PIO]] Port B Data, used for external control (General Purpose 8bit I/O Ports ==Port) FBE2h Dk'tronics Real Time Clock - [[Z80 PIO]] Port A Control FBE0..FBE3 FBE3h Dk'tronics Real Time Clock- [[Z80 PIO]] Port B Control FBE8 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.
== Software ==
Included BASIC and CP/M+ drivers:
* RSX.BAS (loader) and RSX.BIN (binary)- allows to change the time under BASIC, using following RSX commands** |SETTIME,yy%,mm%,dd%,dayofweek%,hour%,min%,sec%** |ASKTIME,@yy%,@mm%,@dd%,@dayofweek%,@hour%,@min%,@sec%** |POKERTC,index%,value%** |PEEKRTC,index%,@value%** |TIMEON,xpos%,ypos%,interval%** |TIMEOFF** |ALARMON,hour%,min%,sec%,flag%** |ALARMOFF* CLOCK.COM - installs the clock under CP/M+ ** Thereafter, it should be accessible with standard DATE command, and, it should add timestamps to files).** According to english manual, time is set by "CLOCK dd/mm/yy hh/mm/ss" rather than by using the DATE command (?)** Unknown how the timestamps are stored on disk? The normal AMSDOS filesystem / directory entries don't include timestamps.** According german manual, something is (the startup message?) "Datomat RTC und Cdos sind Warenzeichen von CMS International" (=Datomat RTC and Cdos are trademarks of CMS International)
* CLOCK.COM - installs the clock under CP/M+ (thereafter, it should be accessible with standard DATE command, and, it should add timestamps to files).== Timestamps ==
Unknown how '''Below method uses Directory Entries with User Number 31 for Timestamps. Which should be incompatible with AMSDOS, so it is probably NOT used in the CPC. On the CPC, the timestamps are <might> be maybe stored on diskin the bootstrap sectors...? The normal AMSDOS filesystem / directory entries don't include timestamps.''
== Review ==Time stamps - P2DOS and CP/M Plus support time stamps, which are stored in each fourth directory entry.
This entry contains the time stamps for the extents using the previous three directory entries. Note that you really have time stamps for each extent, no matter if it is the first extent of a file or not. The structure of time stamp entries is:
1 byte status 0x21
8 bytes time stamp for third-last directory entry
2 bytes unused
8 bytes time stamp for second-last directory entry
2 bytes unused
8 bytes time stamp for last directory entry
A time stamp consists of two dates: Creation and modification date (the latter being recorded when the file is closed). CP/M Plus further allows optionally to record the access instead of creation date as first time stamp.
2 bytes (little-endian) days starting with 1 at 01-01-1978
1 byte hour in BCD format
1 byte minute in BCD format
== Photos ==
<gallery caption="dk'tronics Real Time Clock - 464/664 version">
image:RTC 001.jpg
image:RTC 002.jpg
image:RTC 003.jpg
image:RTC 004.jpg
image:RTC 005.jpg
image:RTC 006.jpg
image:RTC 007.jpg
image:RTC 008.jpg
image:RTC 009.jpg
image:RTC 010.jpg
image:RTC 011.jpg
image:RTC 012.jpg
</gallery>
<gallery caption="dk'tronics Real Time Clock 300dpi scans by Robcfg - 6128 version">
Image:RTC_Front.jpg|Front
Image:RTC_Back.jpg|Back
Image:RTC_Top.jpg|Top
Image:RTC_Side.jpg|Side
Image:RTC_PCB_Top.jpg|PCB Top
Image:RTC_PCB_Bottom.jpg|PCB Bottom
</gallery>
== Reviews ==
Reviewed in [[Amstrad Computer User]], July 1987, pages 28 and 29.
<gallery>
image:Amstrad Computer User8707 028.jpgimage:Amstrad Computer User8707 029.jpg
</gallery>
== Manuals ==
* [[Media:HD146818 datasheet.pdf|Hitachi HD146818 datasheet]]
* [[Media:Dktronics RTC Manual English.pdf|Dk'tronics RTC Manual (English)]]
* [[Media:Dktronics RTC Manual German.pdf|Dk'tronics RTC Manual (German)]]
== Downloads ==
* [[File:DktronicsRtcDriver.zip]] - none such?
[[Category:Peripherals]]
[[Category:Hardware]]