My Gigatron! It very almost works! (Help!)
Posted: 19 Nov 2020, 11:17
Hi there all!
I ordered some PCBs made up of the gigatron a couple of months ago, basically as soon as I could. Then ordered all the various ICs. The only components I had issues getting was the actual crystal itself. I ended up using a 6.4mhz crystal, because I couldn't for the life of me find a 6.25mhz. This may cause me problems, but I could find 6 and 6.4 and a big old nothing down the middle.
I soldered it together and got the basics working in no time, however had to wait until last night to get the ROM programmed, I tried building a EEPROM programmer with an arduino, but couldn't get it working for an IC this big, I tried with the TommyProm and failed. But I went out to a Makerspace and they helped me out.
And I plugged it in, and it worked. First time. The screen popped on and yeah. can't not tell you how much of a surprise that was.
So I went home and realise I'd forgotten to program the ATtiny for the p/2 keyboard. So grabbed an Uno and programmed it using this https://ecetechprojects.wordpress.com/2 ... d-avrdude/ tutorial.
And basically the keyboard lit up, and nothing happens. However if you push a bunch of buttons at random snake will start playing. And if you push a bunch more buttons then you can cycle through the different modes. But that's it.
I've checked over with a multimetre form the keyboard to the AtTiny to make sure the connections are there, as well as from the Tiny to the Shift Register and those connections seem good, I've reflowed them just in case.
I also checked the keyboard out in my PC and it works fine, I also connected it to a pair of shift registers and the data is flowing out of it as it should.
I found another chap here who was having an identical sounding issue. He was having issues with the Fuses. I don't really understand them, but tried to make the same change that he made, and that doesn't' seem to have made a difference. The next step is to go back to the Makerspace and go over the Tiny with an oscilloscope ( I don't have one or know how to use one!) and make sure the signals are poodling out of it fine.
I thought I'd put a screengrab here showing what I put on the Tiny just in case someone here could spot something I've done wrong. I'm 99% sure it's a software error rather than an issue with the hardware
The other thought I had is I could knock up a quick controller on a breadboard to make sure the issue is with the keyboard/ tiny, but I can't work out what the circuit diagram is of the Famacon controller, there seems to be a few about.
Thanks for the help, this project was so good. The guys at the Makerspace were so impressed by the board layout as well as the manual.
All the best,
Aaron
I ordered some PCBs made up of the gigatron a couple of months ago, basically as soon as I could. Then ordered all the various ICs. The only components I had issues getting was the actual crystal itself. I ended up using a 6.4mhz crystal, because I couldn't for the life of me find a 6.25mhz. This may cause me problems, but I could find 6 and 6.4 and a big old nothing down the middle.
I soldered it together and got the basics working in no time, however had to wait until last night to get the ROM programmed, I tried building a EEPROM programmer with an arduino, but couldn't get it working for an IC this big, I tried with the TommyProm and failed. But I went out to a Makerspace and they helped me out.
And I plugged it in, and it worked. First time. The screen popped on and yeah. can't not tell you how much of a surprise that was.
So I went home and realise I'd forgotten to program the ATtiny for the p/2 keyboard. So grabbed an Uno and programmed it using this https://ecetechprojects.wordpress.com/2 ... d-avrdude/ tutorial.
And basically the keyboard lit up, and nothing happens. However if you push a bunch of buttons at random snake will start playing. And if you push a bunch more buttons then you can cycle through the different modes. But that's it.
I've checked over with a multimetre form the keyboard to the AtTiny to make sure the connections are there, as well as from the Tiny to the Shift Register and those connections seem good, I've reflowed them just in case.
I also checked the keyboard out in my PC and it works fine, I also connected it to a pair of shift registers and the data is flowing out of it as it should.
I found another chap here who was having an identical sounding issue. He was having issues with the Fuses. I don't really understand them, but tried to make the same change that he made, and that doesn't' seem to have made a difference. The next step is to go back to the Makerspace and go over the Tiny with an oscilloscope ( I don't have one or know how to use one!) and make sure the signals are poodling out of it fine.
I thought I'd put a screengrab here showing what I put on the Tiny just in case someone here could spot something I've done wrong. I'm 99% sure it's a software error rather than an issue with the hardware
The other thought I had is I could knock up a quick controller on a breadboard to make sure the issue is with the keyboard/ tiny, but I can't work out what the circuit diagram is of the Famacon controller, there seems to be a few about.
Thanks for the help, this project was so good. The guys at the Makerspace were so impressed by the board layout as well as the manual.
All the best,
Aaron