Is there a counter cmos chip that does the following:

I agree. An 8 pin PIC would do a fantastic job and that is probably the route that I will go as it much more flexible, but overall I was just wondering if there was such a chip that I described.

Thanks.

do

zero

It is a long time since I used the part (about 17 years), but Farnell still seem to stock the LSI Computer Systems Inc LS7166 24-bit multimode counter. It has got enough bits for your job, and definitely does up- and down-counts under external control.

Unfortunately, I can't remember exactly how you read the beast - over some kind of bus, if memory serves - and I've got no idea whether you use the carry or borrow flags to do your job. It is a 15-page data sheet, and I can remember that it was hard work to make sense of it.

Hope this helps.

-------- Bill Sloman, Nijmegen

Thanks Bill, I'll take a look at.

It is called a PIC.

At low frequencies only though.

Best Wishes

I know it's not what you're asking for... But if you don't find it (God forbid), it's a classic uC task! ;-)

/A

There probably is and I think Bill had one in mind. But if this is for a series product I'd be careful not to design in a "boutique chip". Some of these are high price and, most of all, could vanish from the market rather quickly.

With uCs, the MSP430 does this nicely, too. It has a 16 bit timer which can be clocked at a very fast clip.

Doing the carry thing ain't so bad either. Many 4 or 8 bit counters come in TSSOP packages, even older ones. Really small.

Regards, Joerg

Since no one else mentioned it, I'll just note that a PLD could also handle this task easily, and could probably do it at higher speeds than a microcontroller.

--Mac

It's a CPLD, if a PIC or AVR isn't fast enough.

Leon

You'll easily make one with a small CPLD, say a Lattice 1016 or a Coolrunner 64 macrocell chip. Both have free programming software, the coolrunner is a lot less thirsty.

Paul Burke