16 Jun
2009
16 Jun
'09
3:52 p.m.
Ethan Dicks wrote:
On Tue, Jun 16, 2009 at 3:42 AM,
Scanning<steven.alan.canning at verizon.net> wrote:
That is in error. The 1802D early versions ran to 3.2mhz accoring to
the data sheet
at 5V. In practice it was more like 3mhz. I have an elf built back
when using the 1802D
running at 2mhz which was the commonly used frequency. It still works!
Allison
Chuck,
You are correct sir. I had forgotten about the dark ages of 4000 Series 10
Volt Bulk CMOS. It's all coming back to me now, the night sweats and the
flashbacks.... I think I even have a 10 Volt CDP1802 lurking in a drawer
somewhere...
I have one 1802D in a ceramic package. ISTR it will push to 10V
(which is required to take it much above 1MHz).
I've been looking for another 10 Volt CMOS
EPROM without any luck. Looks
like building a programmer for the parts he has might be the best approach.
If we knew the source for the EPROM data we might be able to kludge up a
Willem ( sp? ) programmer to program a part....
You don't have to program a CMOS EPROM at 10V Vcc to use it at 10V
Vcc. It's not 10V *only*, it should take any voltage in a wide range
(the exact min and max Vcc depends on exactly what family the part is
from, but 3V-15V is common).
Why wouldn't a 27C64 work? (admittedly, I don't have the data sheet
in front of me). You'd have to make a pin swabber for the destination
machine, but electrically, it's a "C" part, not an "HCT", so
I'd
expect it to work at 10V, but the datasheet will say for sure.
-ethan