VICLink232 UART Cartridge

brain · Post by **brain** » Wed Jan 12, 2005 8:35 pm

I am working on a VIC-20 version of the venerable Swiftlink/DataPump/Turbo232 6551 UART cartridge. I am not done, but my initial work can be seen at http://www.jbrain.com/vicug/gallery/viclink232.

Some features the unit has/will have:

Selected IO1/IO2 pages

NMI/IRQ selection

Selectable 32 byte address block (any 32 byte block in page available)

spare socket for EPROM up to 27C256

spare socket for RAM up to 62256

0-38400 bps and 230400 bps operation

Let me know if there is any interest.

Jim[/list]

brain · Post by **brain** » Sat Jan 15, 2005 8:36 pm

Hmm, no interest or comments....

Jim

6502dude · Post by **6502dude** » Sun Jan 16, 2005 8:55 am

Good idea Jim!

Why two crystals for 6551?

brain · Post by **brain** » Sun Jan 16, 2005 10:10 am

The board started life as a Turbo232 compatible cart, which requires a oscillator because a CPLD divides the clock down for some of the baud rates. But, I wanted the board to also work for folks who just wanted to build a straight swiftlink. Hence, both options. Later, I decided to try just the SL portion first, while I worked on the CPLD, but I left the oscillator. I may need to remove it on this layout because I might need the space for address decoding for the RAM and ROM.

But, that's why it is there.

Jim