Difference between revisions of "Dk'tronics Real Time Clock"
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== Technical == | == Technical == | ||
| − | Contains a HD146818P (RTC), a TMP[[Z80 PIO|Z84C20]]P ([[Z80 PIO]]), three logic chips, and a 3.6V battery. | + | Contains a HD146818P ([[PC compatible RTC chip|PC-style RTC]]), a TMP[[Z80 PIO|Z84C20]]P ([[Z80 PIO]]), three logic chips, and a rechargeable 3.6V battery. |
* Reportedly: DK-Tronics RTC module used the [[Z80 PIO]] chip to address the RTC itself as Port A of the PIO, with a 9-pin user i/o port as Port B. | * Reportedly: DK-Tronics RTC module used the [[Z80 PIO]] chip to address the RTC itself as Port A of the PIO, with a 9-pin user i/o port as Port B. | ||
| − | FBE0h Dk'tronics Real Time Clock - probably [[Z80 PIO]] Port A Data (RTC Data bus) | + | FBE0h Dk'tronics Real Time Clock - probably [[Z80 PIO]] Port A Data ([[PC compatible RTC chip|HD146818P]] RTC Data bus) |
FBE1h Dk'tronics Real Time Clock - MAYBE [[Z80 PIO]] Port B Data (General Purpose 8bit I/O Port) | FBE1h Dk'tronics Real Time Clock - MAYBE [[Z80 PIO]] Port B Data (General Purpose 8bit I/O Port) | ||
FBE2h Dk'tronics Real Time Clock - MAYBE [[Z80 PIO]] Port A Control | FBE2h Dk'tronics Real Time Clock - MAYBE [[Z80 PIO]] Port A Control | ||
Revision as of 11:40, 7 August 2010
Contains a rechargeable battery, five chips, a quartz crystal, a 8bit general-purpose I/O port (9pin male DSUB), and a few odds and ends. The RTC is a HD146818 (which is a PC compatible RTC chip).
Technical
Contains a HD146818P (PC-style RTC), a TMPZ84C20P (Z80 PIO), three logic chips, and a rechargeable 3.6V battery.
- Reportedly: DK-Tronics RTC module used the Z80 PIO chip to address the RTC itself as Port A of the PIO, with a 9-pin user i/o port as Port B.
FBE0h Dk'tronics Real Time Clock - probably Z80 PIO Port A Data (HD146818P RTC Data bus) FBE1h Dk'tronics Real Time Clock - MAYBE Z80 PIO Port B Data (General Purpose 8bit I/O Port) FBE2h Dk'tronics Real Time Clock - MAYBE Z80 PIO Port A Control FBE3h Dk'tronics Real Time Clock - probably Z80 PIO Port B Control FBE8h Dk'tronics Real Time Clock - (unknown purpose)
Not sure if above addresses are correct, for example, A0 and A1 may be swapped...?
PIO Port A seems to be the plain RTC Data Bus, there should be also RTC Read and Write signals, which are maybe found in the unknown purpose port?
Software
Included BASIC and CP/M+ drivers:
- RSX.BAS and RSX.BIN - allows to change the time under BASIC
- CLOCK.COM - installs the clock under CP/M+ (thereafter, it should be accessible with standard DATE command, and, it should add timestamps to files).
Unknown how the timestamps are stored on disk? The normal AMSDOS filesystem / directory entries don't include timestamps.
Downloads
File:DkronicsRtcDriver.zip - none such?
Timestamps
Time stamps - P2DOS and CP/M Plus support time stamps, which are stored in each fourth directory entry.
This 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 <might> be maybe stored in the bootstrap sectors...?
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
Review
Photos
- dk'tronics CPC6128 Real Time Clock 300dpi scans by Robcfg
Front
Back
Top
Side
PCB Top
PCB Bottom
