Can I use a clockport RTC if I have an A1200 accelerator with RTC?

[bubba]

I have an A1200 with a Blizzard 1230 IV.  Instead of replacing its battery, I'd rather just get a clock port clock card to keep the time, like the new one from Individual computer.

I don't know how the clock IO addressing works on the amiga.  Is it possible to have both a clock attacked to the clockport and a clock on the accelerator (with a dead battery).  Or, do they conflict?

Thanks!
Bubba

[bubba]

I found this at http://www.ianstedman.co.uk/Amiga/amiga_h_w/clock_port/clock_port.html:

The region of $DC0000 to $DCFFFF is used by an accelerator card that has a built in clock as the RTC_CS signal goes to the A1200 CPU connecotr and can not be used if you have a clock, simple really!

Does this means the signal doesn't go to the accelerator if a clock is installed on the motherboard or vice-versa?

-Bubba

[Zac67]

Don't think that'll work. Looking at the schematics, it's the very same _RTC_CS that runs to both clockport and trapdoor slot. The battery may be dead on the accelerator but the RTC chip is there and both RTCs will get selected simultaneously, ending you up with random data on the bus.

I'd fix the battery - if possible with a battery holder. If you've got someone with some soldering skills it's a matter of five minutes. Or cut the CS trace on the board. :-/

[yssing]

Why not just change the battery?
I just changed the battery on my Blizzard 1260 with a battery holder from amigakit, it worked right away