New photo - RCA eval board
- I've just uploaded a photo of my RCA CDP18S020 COSMAC eval board,
circa 1976. Sorry for the poor quality, but I have a really cheap
digital camera :-(
The board came with a 2.0 MHz CDP1802 CPU, an RCA hex monitor in CMOS
ROM, two CDP1822 CMOS RAMs (256 X 4 bits each), and LEDs on every CPU
address and data line. Great for debugging - you can single step
your program and watch the blinkenlights.
To this, I added a 6-digit hex display with a 74917 decoder/driver, a
24-key keyboard, battery backup for the CMOS RAM, and eight 5101 NMOS
RAMs, for a whopping total of 1,280 bytes of RAM.
I wrote a hex monitor that uses the keyboard and display, and burned
it into a 2716 2K X 8 NMOS EPROM. This is instead of the original RCA
monitor which needed a serial terminal (a big deal in 1976).
Applications included a music generator (using a speaker on the CPU Q-
line), real-time clock display (using a 5V 60Hz input on the CPU EF1
line), and a port of CamelForth (work in progress).
E-mail me if you want any more details, or just to reminisce.