Real time Clock project...

[Waltermixxx]

I'm hoping to add a real time clock to my ste.
I was thinking about using the cartridge port....

I recently ordered a couple of these:

http://cgi.ebay.ca/VT-100-Terminal-Emulator-Cartrige-Atari-1040-ST-STE-New-/130470554137?pt=LH_DefaultDomain_0&hash=item1e60a6aa19

just so I had a connection to the cartridge port, I thought I could remove the rom's and use the cartridge
to build a real time clock, or perhaps use the connections for a cartrige port IDE interface... which is why i
bought two of them ( incase I gub something up )

[Petari]

I don't think that you can use more than one cartridge port adapters (interfaces) at once. At least chances that 2 at once work are pretty low. Usually adapters use some tricky way to achieve writing to that port (what is not in design spec).

Then, doing RTC with cartridge seems as overcomplication. It is pretty simple to add intern clock circuit to ST(E). 2-3 chips, battery, crystal. And it will be supported by any TOS at 1.02. So, no need for some extra SW as you will for sure need woth cart port clock.

[Waltermixxx]

I will check that out

[Arthur]

Hello, the best way I think is to insert the clockchip from Mega STE (RP5C15 from Ricoh) or Falcon,TT (Dallas 12887, 1287 etc.) in the ST or STE. But I think there are not all signals available in the small ST and STE and i can't rebuild all required signals.

[Petari]

You need simple logic which will attach those chips - irrelevant is it Ricoh or Dallas   to the bus , only 4 lowest bits used.
There was schematic in ST Magazin (German) somewhere about 1990. And I made clock circuit according to it. If remember correct, there was only Ricoh chip and 74LS132 + crystal + couple passive coponents.  Someone should dig that ST Magazin out ...
But if not, I can do circuit schematic ...  No GAL in any case :-)  I removed it from dismantled 520 ST years ago, so don't know where was exactly connected . Data is no problem, it goes for sure on D0-D3. Knowing exact HW address is not too hard to design proper logic for address decoding, or in other words to select clock chip at certain address space.
And it will work without extra SW in any TOS 1.02 or higher.

[Arthur]

I would prefer the Dallas 12778 because I have 4 new Dallas chips from Maxim as sample. The chips contains a batterie and one oszillator. I don't know the exact HW adress from the NVRAM chip. I check this in "The Atari Compendium" on side 751 in the PDF.
http://www.schupp.lt/Atari/ckurs/download/TAC.pdf

R e a l T i m e C l o c k ( 1 4 6 8 1 8 A ) > the Dallas is compatibel

Location(s)     Size              Type        Meaning
0x00FF8960   OB I/O Real Time Clock Address Register
0x00FF8962   OB I/O Real Time Clock Data Register
0x00FF8964 – 0x00FF89FF N/A I/O     Unassigned

     

[Petari]

This is it. You need first to write which register to access in ..8960, then R or W to/from ..8962. All data is  BCD format.
For year, I guess 4 digits, for month 2 digits etc.
What need to design is address decoder - which will activate on those addresses. Normally A1 of CPU must go on pin of RTC which selects address or data register access. Usually, not full decoding is made, for simpler circuit - therefore we have shadow addresses until ..89FF.

So, logic must use addresses A23-A4 . But in this case I think that it is simplified by using some common line from Glue chip, which is already decoded, so can solve it with very simple logic - 74LS132, what is 4 x NAND Schmitt trigger.

It would be good to see that CD schematic  

I googled little, and found this:  http://www.asamnet.de/~hilgarte/uhr.php

It is with GAL, likely same logic as in Mega ST.  Dallas chip may have different pin layout.

[Arthur]

Hallo Peter, you are right, for the small Ataris are the Ricoh clock the better solution.

Thx for your help and happy Easter.

Arthur

Btw, i can't found the documentation for the famous IDE 2.0 Interface and 4xFlash from the dreamteam ppera and popsel. The old link http://www.infofront.de/andreas/index.htm does not work. Can you put the files on your website?

[Petari]

Packages are here:  http://atari.8bitchip.info/FlashableTOSx4.rar
and here: http://atari.8bitchip.info/ide2.rar

I need to do some updates on pages too ...