The next step was to find a processor that had many free pins to drive the 15 for the address bus and 8 for the data bus, for that then I used and AVR128.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiyhLvooWWfAgTPP1ve8h4ShUZX5RboQkbBnpC2eKKLA1s6hLlIKkqEEFAMRzTwmEy-2I_JmBrhgLxefLPlgxLTf8zo8Ee4PDQymuF886BR1x5dxOXAaariyLDzQavQhmtJx1AwfPhp0DDO/s400/IMAG0299.jpg)
If you look at the cartridge 'pins', you'll see a cable soldered to one of them, that is the HALT line of the Z80, controlling this pin I can freeze the Z80, this way the data and addresses buses are free and my AVR can write and read data from my RAM.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiIy_NDhO_IFKWUMIz55XDrmWR7KpvC3gSibWm6p_KGEGDzKurUZyEv3YhMPYALIdL7vnPOajkBCLFS9VcETiOQZ-VJ-jmel0Krk2lVcvqfxyivuPOuAfClmB4HgrYNth10Q9EZek4wCUbT/s400/IMAG0297.jpg)
This is how the whole setup looks like once connected, the big chip is the AVR .
I can write programs in the RAM in two ways:
1) Connecting the AVR to my computer through a serial port and use a little loader to upload apps.
2) Write the app I want to upload in the AVR's flash and have it write it to the RAM when the Game Boy is turned on.
So, bottomline :-) It worked for small apps < 16Kb but it didn't work for bigger apps, so I think this post will have a second part someday, stay tuned!
hello could you leave me a contact address where I can contact you? facebook, instagram, whatsapp or an email... I would have a certain urgency to contact you
ReplyDeletemy mail is Alex.spadaro@hotmail.it