Post by nes4life on Sept 19, 2020 5:45:50 GMT -5
Hey all,
I've started playing around with fitting multiple BIOS in my Vectrex and selecting them with switches.
Here's the initial prototype:
So far you can select between stock GCE and stock MB BIOS and then have the option of their Fastboot variants. GCE Fastboot was taken from VIDE (it's literally just two bytes difference making the Vectrex come out of a loop early but long enough for you to see the start-up screen) and I ported that to the MB version.
I'm looking at possibly adding one more switchable option to these; a built-in debug 'cart' instead of Minestorm. Something like 'test cart 4' but obviously assembled for the BIOS address space. I haven't looked at disassembling 'Test cart 4' and then reassembling it but perhaps I should look at having something built from scratch anyway. Something to exercise all the RAM, draw specific vectors or text, play specific noises or music in a particular music channel (or the extra 'digital-out'), beep on button presses and show you the calibration of the joystick etc.
If someone has already made a pretty impressive test cart then I'd love to get permission to use it with this. Otherwise I'll roll my own or work with someone to make one.
I'm designing and printing a generic EPROM adapter that includes DIP switches and then I'll either sell these as bare boards or as kits as cheap as I can. Otherwise, people are welcome to roll their own. I will see about making all of this available on Github but to start with I'll see if there's someone in the US who can print and distribute the boards for me Stateside. I can do Europe etc.
The tricky bit with modifying the BIOS is that the built-in EPROM is typically soldered in... so people will need a competent tech to do that desoldering work to fit a socket. But once socketed, the world's your oyster! I've also made a few custom BIOS for a few friends and I'll share them on YouTube in due course.
I've started playing around with fitting multiple BIOS in my Vectrex and selecting them with switches.
Here's the initial prototype:
So far you can select between stock GCE and stock MB BIOS and then have the option of their Fastboot variants. GCE Fastboot was taken from VIDE (it's literally just two bytes difference making the Vectrex come out of a loop early but long enough for you to see the start-up screen) and I ported that to the MB version.
I'm looking at possibly adding one more switchable option to these; a built-in debug 'cart' instead of Minestorm. Something like 'test cart 4' but obviously assembled for the BIOS address space. I haven't looked at disassembling 'Test cart 4' and then reassembling it but perhaps I should look at having something built from scratch anyway. Something to exercise all the RAM, draw specific vectors or text, play specific noises or music in a particular music channel (or the extra 'digital-out'), beep on button presses and show you the calibration of the joystick etc.
If someone has already made a pretty impressive test cart then I'd love to get permission to use it with this. Otherwise I'll roll my own or work with someone to make one.
I'm designing and printing a generic EPROM adapter that includes DIP switches and then I'll either sell these as bare boards or as kits as cheap as I can. Otherwise, people are welcome to roll their own. I will see about making all of this available on Github but to start with I'll see if there's someone in the US who can print and distribute the boards for me Stateside. I can do Europe etc.
The tricky bit with modifying the BIOS is that the built-in EPROM is typically soldered in... so people will need a competent tech to do that desoldering work to fit a socket. But once socketed, the world's your oyster! I've also made a few custom BIOS for a few friends and I'll share them on YouTube in due course.