RTC guide?

Current solutions and designs.
User avatar
Bikerbob
Posts: 162
Joined: Fri Nov 10, 2017 7:30 pm
Location: Mississauga, ON
Contact:

RTC guide?

Post by Bikerbob » Sat Nov 09, 2019 10:06 pm

Could one be made?

AKA - what machines have.. what does not.. etc..

I have a UltraSatan with a RTC on it.

Not only on my 1.04 STF but also on the 2.06(TOS SWITCHER) STE I get 08-11-28(the year) ... I thought 2.06 had it fixed??

I am using the Ultrasatan config GETCLK program.. and I know the RTC is storing it as 19 (I see it in the startup)

I have read a lot about the various hardware to do it.. I see FMCII with exxos and others and building an inboard one etc.. I am trying to get the DESKCART! working.. but its not so much about the hardware circuit.

I assume those that do not have one built in - ALL OF THEM?? ST, STF, STFM, STE? all these machines would report a 2019 date wrong?? STF or STE mine reports year 28 - SO this is the software used to read it? But the UltraSatan was written only 7-8 years ago??

I am finding this all very confusing and I cannot seem to find reading to LEARN ME.. anyone?

James

User avatar
exxos
Site Admin
Site Admin
Posts: 8560
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: RTC guide?

Post by exxos » Sun Nov 10, 2019 1:18 am

There is a lot of info by RJ on this page in pdf format.

https://www.exxoshost.co.uk/atari/last/RTC/index.htm

Not all RTC chips are the same. The FMCII is different than the Falcon RTC and different I assume to ultrasatan RTC (I never used it), not sure about RTC in the MEGA ST but likely different again . So you need the proper program to talk to the RTC chip in use.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

User avatar
rubber_jonnie
Moderator
Moderator
Posts: 1485
Joined: Thu Aug 17, 2017 7:40 pm
Location: Essex
Contact:

Re: RTC guide?

Post by rubber_jonnie » Sun Nov 10, 2019 10:24 am

exxos wrote:
Sun Nov 10, 2019 1:18 am
There is a lot of info by RJ on this page in pdf format.

https://www.exxoshost.co.uk/atari/last/RTC/index.htm

Not all RTC chips are the same. The FMCII is different than the Falcon RTC and different I assume to ultrasatan RTC (I never used it), not sure about RTC in the MEGA ST but likely different again . So you need the proper program to talk to the RTC chip in use.
You beat me to posting that link :)
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

tzok
Posts: 150
Joined: Sat Dec 30, 2017 2:27 pm

Re: RTC guide?

Post by tzok » Sun Nov 10, 2019 10:40 am

Some machines report weird years due to strange and completely unneeded TOS patches. I have investigated the problem thoroughly and came to the conclusion, that the only Y2K non-compatible part in Atari ST is IKBD, but it is only used to keep RTC during reset. If machine has a proper RTC module it doesn't need to use IKBD RTC routines at all. The limit is year 2059. More concerning is Unix time limit of year 2038.

Except Falcon, none of all-in-one Atari ST series computer had a battery backed up RTC. Desktop series had a proper RTC (yet I think in Mega ST it was optional), but it might not be Y2K compatible.

viewtopic.php?f=10&t=544

Year 28 is a result of reading a year from unmodified IKBD, so if you have something running in the background that polls the IKBD for date/time, you will end up with year 2028. Uninitialized IKBD will always return year C8, and it would reject initialization with anything higher than 99. Strangely Atari Control Panel (or rather the GEMDOS Tsettime() function it calls) is Y2K compliant, and if you try to set year 19, it would actually send a correct value 0xB9 (119 which corresponds to 2019) to the IKBD RTC. Yet the IKBD will reject that and stay uninitialized (only for year part, rest of fields will be accepted).

With UltraSATAN you can't use CONTROL.ACC nor XCONTROL.ACC to set the clock. You have to AUTOload it's clock set utility (US_GETCL.PRG) on each boot (as TOS 2.x polls IKBD clock as a first thing after reboot), and use a dedicated clock adjust utility to set the date/time for the first time (US_SETCL.PRG).

User avatar
rubber_jonnie
Moderator
Moderator
Posts: 1485
Joined: Thu Aug 17, 2017 7:40 pm
Location: Essex
Contact:

Re: RTC guide?

Post by rubber_jonnie » Sun Nov 10, 2019 11:06 am

tzok wrote:
Sun Nov 10, 2019 10:40 am
Desktop series had a proper RTC (yet I think in Mega ST it was optional), but it might not be Y2K compatible.
I'm just working out how to set the clock in my Mega ST4, but it certainly has a built in RTC with 2 AA cells for keeping time with power off. I think the chip is a Ricoh, willhave a look later.
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

tzok
Posts: 150
Joined: Sat Dec 30, 2017 2:27 pm

Re: RTC guide?

Post by tzok » Sun Nov 10, 2019 11:11 am

I'm not sure if Ricoch chip in MST is Y2K compilant. If it doesn't work you either have to use some autoloaded software patch or a TOS patch to use it. Alternative is to disable it and build/buy another RTC solution (UltraSATAN, ComosEx).

Ricoh RP5C15 for sure uses only 2 digits for year in BCD format, but I'm not sure if it could handle pseudo-BCD years like B9.

User avatar
rubber_jonnie
Moderator
Moderator
Posts: 1485
Joined: Thu Aug 17, 2017 7:40 pm
Location: Essex
Contact:

Re: RTC guide?

Post by rubber_jonnie » Sun Nov 10, 2019 11:54 am

tzok wrote:
Sun Nov 10, 2019 11:11 am
I'm not sure if Ricoch chip in MST is Y2K compilant. If it doesn't work you either have to use some autoloaded software patch or a TOS patch to use it. Alternative is to disable it and build/buy another RTC solution (UltraSATAN, ComosEx).

Ricoh RP5C15 for sure uses only 2 digits for year in BCD format, but I'm not sure if it could handle pseudo-BCD years like B9.
Yep, it's qute possible it has Y2K problems. I do have a Y2K patch so will have a play, but I worked on reverse engineering the FGMC II circuit, which is the board that exxos sells in his store, so I have 3 or 4 ROM port clocks and it wouldn't be too hard to fit that internally at all, as I did for my STE.

I wonder if there is a Y2K compliant version of the Ricoh? The DS1216 was replaced with the DS1315 so it's possible Ricoh did the same with theirs.

Either way I do have clock solutions I can use easily.
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

tzok
Posts: 150
Joined: Sat Dec 30, 2017 2:27 pm

Re: RTC guide?

Post by tzok » Sun Nov 10, 2019 12:06 pm

RP5C15 was made with Z80 in mind, so I doubt they bother to update it for 21st century. On the other hand, the DS1315, even without century bit could support 21 century dates, as it accepts and runs years like 0xB9.
There were similar RTC modules at that time, for example Seiko/Epson RTC58321 and OKI MSM58321, but neither of them was Y2K compatible.

I have found similar Y2K RTC ICs but they are not directly compatible:
http://www.ti.com/lit/ds/symlink/bq4802ly.pdf
https://datasheets.maximintegrated.com/en/ds/DS1500.pdf

User avatar
rubber_jonnie
Moderator
Moderator
Posts: 1485
Joined: Thu Aug 17, 2017 7:40 pm
Location: Essex
Contact:

Re: RTC guide?

Post by rubber_jonnie » Sun Nov 10, 2019 12:16 pm

tzok wrote:
Sun Nov 10, 2019 12:06 pm
RP5C15 was made with Z80 in mind, so I doubt they bother to update it for 21st century. On the other hand, the DS1315, even without century bit could support 21 century dates, as it accepts and runs years like 0xB9.
There were similar RTC modules at that time, for example Seiko/Epson RTC58321 and OKI MSM58321, but neither of them was Y2K compatible.

I have found similar Y2K RTC ICs but they are not directly compatible:
http://www.ti.com/lit/ds/symlink/bq4802ly.pdf
https://datasheets.maximintegrated.com/en/ds/DS1500.pdf
Good info, thanks.
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

stephen_usher
Posts: 377
Joined: Mon Nov 13, 2017 7:19 pm
Location: Oxford, UK.
Contact:

Re: RTC guide?

Post by stephen_usher » Sun Nov 10, 2019 1:04 pm

A complication to all this is that different TOS versions seem to use different start dates.

On the same hardware (STE) the UltraSATAN clock setting utility will set the year differently (I think it's a 9 year difference) depending upon whether the machine is running 1.62 or 2.06.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.

Post Reply

Return to “RTC (Real time clock)”