Re: [uCsimm] IDE interface?

From: Geoffrey Wossum (
Date: Wed Jul 05 2000 - 17:01:26 EDT

> they release a soft IDE interface on a little PIC !
> If they can do it on a PIC it should be easy to do it on uCsimm/68k !
> The only problem is that uCsimm has to few IO to drive IDE (32bits + some
> control lines). You have to use multiplexors/latches with levels convertor
> (3V->5V).

Or you could make an IDE controller using a PIC with a PSP, and interface
the PIC to the uCsimm using the PSP port. We've taken a PIC with I2C bus
controller firmware and interfaced it to a uCsimm via the PIC's PSP port.
Works nicely. We used 74LCX series chips to do the level conversion.

We used a 16F877 for the PIC ($6 from Arrow in small quantities [4 or
more]). We used a 74LCX245, a 74LCX08, and a 74LCX04 for voltage shifting
and address decoding (we had another device connected to the bus off the
uCsimm). I think it was less than a dollar for the 74LCX chips. The
'08 was only needed for the address decoding.

The 74LCX series are only available surface mount. You'll need a 5V
supply for the PIC and a 3.3V for the uCsimm and the LCX chips.

Geoffrey Wossum
Project AKO -
Internet Imperialists -
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