Hello everyone!
I'm new here, but actually I've been visiting this forum regularly for a couple of months - it's a great resource and community. Now I decided to register, because I've got a question I wanted to ask You.
I made couple of cartridges now using the 27C801 - i really like the method, it's super easy to work with, even better with swapbin. But this is an EPROM - and I don't have a UV eraser. They are also much harder to find than all of the modern flash mems.
Okay, so I have a s#itload of 29F016s and nothing to do with them. They are super-dooper cheap, easy to solder, generally easier to find and better. Earlier I found out that I can actually wire them up in place of the 32 pin maskroms, and use as an 8Mbit memory, but hey, that's a huge waste right? So I thought to myself: what if I could configure the 74LS139 to decode that full 2MB of them for me.
Now I'm not into electronics that much, but:
here's what I came up with (there's also some stuff I used to figure out how all this works):
The big question is:
From what I understand everything will work if I shift the address one place towards the MSB? (Because the chip is 2MB, 2 times more than 27C801)
Also sory, I couldn't find a 36 pin socket in EAGLE (great program, by the way) parts library (and I didn't feel like making one from scratch now), so let's just pretend that these sockets are 36 pin, okay?
I'm new here, but actually I've been visiting this forum regularly for a couple of months - it's a great resource and community. Now I decided to register, because I've got a question I wanted to ask You.
I made couple of cartridges now using the 27C801 - i really like the method, it's super easy to work with, even better with swapbin. But this is an EPROM - and I don't have a UV eraser. They are also much harder to find than all of the modern flash mems.
Okay, so I have a s#itload of 29F016s and nothing to do with them. They are super-dooper cheap, easy to solder, generally easier to find and better. Earlier I found out that I can actually wire them up in place of the 32 pin maskroms, and use as an 8Mbit memory, but hey, that's a huge waste right? So I thought to myself: what if I could configure the 74LS139 to decode that full 2MB of them for me.
Now I'm not into electronics that much, but:
here's what I came up with (there's also some stuff I used to figure out how all this works):
The big question is:
From what I understand everything will work if I shift the address one place towards the MSB? (Because the chip is 2MB, 2 times more than 27C801)
Also sory, I couldn't find a 36 pin socket in EAGLE (great program, by the way) parts library (and I didn't feel like making one from scratch now), so let's just pretend that these sockets are 36 pin, okay?