Reset IC for a 68000 ?

Question

I have a 20 year old PCB with a dodgy custom chip which, as one of its functions, provides the initial power on reset to a 68000 CPU.

It's only the reset part of the custom IC that is faulty, therefore I was thinking of severing the track from the custom IC's reset pin to the 68000 and adding in a modern, small reset IC.

What type of IC would be suitable for a 10 MHz 68000 CPU?

I can find various types in my online parts catalog:

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but am not sure which one would be suitable for the 68000.

They are available in various forms - all I want is something small that preferably only requires power with a Reset line output. I see there are even some that look like transistors which would make them nice and easy to the board (as opposed to a 4 or 8 pin DIL device).

Thanks

Rich Webb · Accepted Answer

Microchip's MCP100 is a candidate. TO-92 package, active reset line (vice open collector), reasonably cheap and available.

erm the 68K's reset *is* active low? It's been a while ...

jamma-plusser · Answer

Many thanks. There are so many though! Which one out of this lot (notSMT/SMD though):Yup, active low (so is high when the 68000 is working okay).Cheers!

Rich Webb · Answer

Depends on where you want the reset point. From what they haveavailable, I'd go with the -475 flavor; that's 4.50

WangoTango · Answer

Dallas has the DS1233 IC and it works with the Motorola ICs that use a bidirectional /RESET line, like the 68K family. It comes in a 3 pin TO-92 package, so easy to hook up. We use them by the 1000s on the HC11 family and I would be more than happy to throw a couple in an envelope for you. The one that triggers on 4.75V should work just dandy.

jamma-plusser · Answer

Will do, thanks.

jamma-plusser · Answer

Thanks for the kind offer - I'm in the UK, how about you?

WangoTango · Answer

Nope, and I have my newsgroup reader set up to suppress the full header information on the posts or I would have realized that. Amazing what information you can suppress with the right combination of switches. I could still do it, but there is no telling how long it would take to get there and in what shape the parts would be in by that time too.

jamma-plusser · Answer

Not to worry, thanks anyhow. I'll keep looking.Appreciate your offer of help though!

Reset IC for a 68000 ?

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