15 Mar
2013
15 Mar
'13
12:51 a.m.
On Thu, Mar 14, 2013 at 2:00 PM, Paul Birkel <pbirkel at gmail.com> wrote:
The early PDP-11 uses a ?DEC 1801 UART? in multiple
modules. I?ve had no
luck identifying a comparable chip that could be substituted when doing
repairs as there?s a remarkable dearth of information regarding the
characteristics of this part, excepting the pin-out as seen in engineering
drawings. (No, I haven?t yet tried pin-out matching ... next step.)
I haven't checked schematics myself, but the TR1602 dates back to
1971. It's a 40-pin UART, the first, IIRC.
Datasheets aren't hard to find for it. The receive bus is pins 5-12, the
transmit bus is pins 26-33, and for power, +5 is on pin 1, -12 is on pin 2
and GND is on pin 3.
-ethan