The qq22. net Computer Rooms

updated 28_oct_2008
Some of the processors I've worked with over the past thirty years...

The RCA 1802


1802
1802
RCA CDP1802CD
RCA CDP1802ACE

Introduced by RCA in about 1974, and replacing the earlier 1801. (2-chip processor). The 1802 was a fast
and neat 8bit c-mos processor with versatile registers that could be used in 16bit or 8 bit mode. 32x 8bit,
or 16x 16bit. The processor could run at over 6MHz, and be put into standby to save power, with the clock stopped.

These processors didn't see too much use in the home-computing field. And have been used for applications where
power consumption is to be kept to a minimum. Often used with only a few kb of memory in control applications.
They can still be found in some battery powered devices, military communications / encryption systems and terminals,
communications/survey satellites and probes. They have a high resistance to radiation due to their silicon-over-saphire
construction. I first encounterd them in 1990 when I was (without the knowledge of their owners, British Telecom).
Modifying/hacking the firmware in some BT equipment. They were used in coin and card operated pay-phones.

The lower of the two pictures above shows an 1802 in a military encrypted data terminal. These terminals have
three 1802 processors inside to control the user interface, the radio interface, and the data encapsulation. These
and their support devices, display, etc.. are run from the radio set's power supply. This will in many cases be a Ni-Cd
battery pack. The low power requirement of these devices makes them well suited to these, and similar applications.

pinout of 1802 cpu
block diagram of 1802



All images and text copyright (c) 2003-2007 T.R.Bluck. OES Engineers / qq22.net