jaquinn
Experienced Member
It has taken a while but I finally got the PCB completed and tested for the Model 1 Expansion Interface for FreHD. This board upgrades a stock 16K Level II Model 1 to 48K and adds support for FreHD autoboot.
A write up along with design files are available at http://www.quicktrip.co.nz/jaqblog for anyone who wants to have a go building one and providing feedback. We are testing on a few Model 1's at the moment to make sure there are no compatibility or other undiscovered issues so any feedback from builders is appreciated.
The only known issue is that the V1 Schematic and PCB (included in the design files) does not pull up the FreHD /EXTIOSEL and /WAIT signals to VCC. This isn't a problem when the FreHD is connected because it drives these signals but when using the board without a FreHD these signals float. It doesn't seem to cause problems in my testing but adding two pull-up resistors is a good idea.
A write up along with design files are available at http://www.quicktrip.co.nz/jaqblog for anyone who wants to have a go building one and providing feedback. We are testing on a few Model 1's at the moment to make sure there are no compatibility or other undiscovered issues so any feedback from builders is appreciated.
The only known issue is that the V1 Schematic and PCB (included in the design files) does not pull up the FreHD /EXTIOSEL and /WAIT signals to VCC. This isn't a problem when the FreHD is connected because it drives these signals but when using the board without a FreHD these signals float. It doesn't seem to cause problems in my testing but adding two pull-up resistors is a good idea.