SURFACE MOUNT COSMAC VIP

I have been working on a surface mount COSMAC VIP for a while now. I decided to build this after finding out that Intersil made a surface mount version of the 1802.

It works just like the original RCA VIP. This computer will read in my old cassette tapes. It even works with the old expansion boards.

When I finally located a CDP1802ACQ, I started designing the circuit.

The circuit is basically the same as a fully expanded RCA COSMAC VIP. I did a few updates though. Here is a list:

Audio jacks instead of wires

Video jack instead of wire

Onboard speaker (VP-711 had one, VP-111 did not)

Speaker mute switch.

32K EEPROM for VIP monitor (wired as 512 bytes on this version)

32K of RAM which can be configured as 4K, 16K, 24K or 32K with shorting pads on underside of PCB

Battery backup for RAM

Battery backup bypass by shorting pads on underside of PCB

2 Amp onboard switching 5 volt power supply

Shorting pads on underside of PCB to allow use of VP-590 Color Board with out removing chips

 

The CDP1802ACQ

 

Here are some photos of the finished board:

 

 

 

SIZE COMPARISON

 

 

As you can see in the photos, I used some through hole parts because I couldn't find suitable surface mount versions.

Non-surface mount items:

- Keypad

- 44 pin expansion connector

- 44 pin I/O connector

- Video jack

- Backup battery socket

- C&K RUN/RES switch

I used the C&K switch so my VIP would have the same feel as the RCA version. I used a though hole coin battery socket because the stress exerted while installing or replacing the battery could rip up the traces.

 

CONCLUSION

 

I made the PCB the same size as the original RCA VIP. I have a bunch of space for adding circuitry in future versions.

Comments and questions welcome.

ED

 

Please feel free to contact me at the e-mail address in this image: