Technical Information

I've tried to put together some technical information for you super-hackers.

DTV2 - Schematic - This is the original shematic for the DTV-2 design. It is slightly different than the production model, and different from the hummer. But it is close enough to be helpfull. It is in adobe PDF format.

DTV1 - schematic - A schematic of the original NTSC Version 1 DTV. It is poor quality, in a PNG graphic format.

Programming document - This is a document written by the designer of the DTV2 chip documenting all of the extended features. It doesn't cover standard C64 programming, just the parts that are new.

Adding new programs to your flash - This article explains the format of the flash data and filesystem.

How to use the new 256 color video mode - Here you can learn how to activate the 256 color video mode and how to send information to it.

GRTEXT - My ML Graphics and text libraries for the 256 color screen.

How to read the ADC -How to read from the built-in ADC (Analog-digital-converter)

PS/2 Mouse Driver - How to use a PS/2 mouse on your DTV

Segment Mapper tutorial - A PDF document showing how to use the segmapper.

BUG! - You'll find that occasionally the keyboard will change and some of the letters showing up aren't what is being typed. There are several things that can cause this, and it is also a bug present in the version 1 DTV. However, usually pressing SHIFT or Caps-Lock will immediatly solve the problem.

BUG! -It appears there is a bug in the kernel on this unit involving the save to disk routine. The load routine works fine, but attempt to save anything from BASIC or any ML program which uses the kernel save routines, and the file will be larger than expected and usually corrupted. The good news is that it can be fixed. There are two solutions. One solution is to flash the kernal with a patched version. That is what I did. The other solution, if you aren't up to risking a flash, is to use the kernal-patcher program and simply install a patched kernal in upper memory and run from that while you are doing anything requiring the use of the save function. When you power off and back on, you'll be back to the original kernal with the bug.

It is also worth mentioning that the power switch cuts the ground, not the +5V as one might think. The reason is that there is a small resistor designed to drain any current from the capacitors on the board. The idea is that when you shut it off, the memory has to be dumped before you would be able to boot it back up properly. So the way the power switch is wired up is for that purpose. However, people have found that if you connect something else up to the board (anything, video cables, disk drive, etc) that shares a common ground you might find the unit mysteriously stays turned on.