Recent content by jbevren

Dividing the memory into 8k blocks makes it easier to build a ram or rom cartridge. With a 6264 or similar static ram all you have to do is hook up vr/w, a BLK signal, address, and data bits for example. I'd personally prefer the whole address bus, but in an era where ram was expensive and...

The VA and BD lines are probably not extended to the cart port due to load limitations of the VIC chip. That's pure guesswork on my part. That, and the video address bus is only 14 bits. :P The 3k hole I think is an economical decision made with the end user in mind. Here's a theory of mine...

Exactly! This had to be done as the vic chip is hardwired in silicon to respond to address 4096 (as noted vaguely in the datasheet). It boggled me for a long while that the VIC chip has no chip-select input. Flipping the address map around can also be confirmed by the 'default' character...

To keep things simple you can use the character ROM socket. It has all but two of the signals you need. I did this with my 8kinside project, which places a TSOP 6264 8k SRAM underneath the character ROM. The tricks are few: Tie VA13 to CS (active high, pin 26 on the SRAM) right on the ROM...