23 Feb
2012
23 Feb
'12
12:26 p.m.
I want to bould my own PDP11 some day but in an other way as other people
here :-)
I want to build an Bit Slice CPU out of AM2901 Chips to emulate the
PDP11 CPU. As a prt of the design I'LL need some very fast Proms for the
microcode and I've found the AM27C291,TMS27C291 and CY7C291 Chips, they a=
re
fast and big enough (2Kx8 and 25-35ns).
I'mm looking now for a data sheet from the CY7C291 that describes the
programming algorithm, getting a datasheet is easy on
Unfortunately, I have a Cypress databook that includes this device.
I say 'unfortuantely' beucase I also have the 'programming information'
section. It's useless!.
It's 2 apges long epxlaining in general terms how these devices a
differnet from other EPROMs. It then refers you back to the data sheet.
There is a little table there which shows how the verios chip select pins
are re-assigned in programmign mode (you apply Vpp -- 12.5V -- to one of
the thm, then other is the programming pulse, etc. Address inputs are as
normal, you apply tjhe data to be programemd onto the data (output)
lines, as you'd expect). But I guess you've seen all that as you have the
data sheet.
What I can't find anyware is a timing diagram. How long should the
programming pulse be, etc. And I guess that's what you need to know.
I suspect, als, that unless somebody hwas got this information out of
Cypress years ago and stil lahs it, you're not goign to find it :-(.
-tony