exxos's Atari, Amiga & retro forum

czietz wrote: 09 Feb 2020 11:33

PaulJ wrote: 08 Feb 2020 20:07 The LightningST decode is to slow for the eprom emulator.

To be honest, I rather doubt that. When just passing ROM2 through (for booting or for access to the 0xFC0000 - 0xFEFFFF address range), the Lightning ST adds about 7 ns delay. When decoding a ROM access by itself (to 0xE00000 - 0xE7FFFF), the Lightning ST chip select output becomes low within 8 ns of the falling edge on /AS. These delays are small enough even for slow EPROMs.

I have to say I was also surprised but I did post the picture of the attempt to boot using Lightning and the pin 20 tap. I was even more surprised when moving to pin 2 of U12 allowed it to boot. However moving to pin2 did pickup the 0-7 decode but corrupted the full $fc0000 decode and worked with intermittent crashes when the machine warmed. So when I went to Exxos's board it worked flawlessly but I attribute this to the way he generates the entire decode signal. He creates the entire decode from scratch off the bus signals and doesn't leverage the processed decode that originates from the glue and is additionally processed to make a u9/u10 decode. I suspect the EPE is slow needing a faster decode signal. For normal eproms I suspect the Lightning decode signal works fine. My effort was getting the EPE working since I find its capability advantageous and wanted to have working units. Since I want to continue to use the Lightning card I will most likely generate my own decode to drive EPE and put the Lightning back in. Maybe I should have said the EPE was slow since the Lightning uses the standard method of creating a 0-7,$fc0000, and $e00000 decode.

I guess bottom line is I have no idea why the EPE and Lightning don't work together at this point in my mega but its an easy solution for me to use what works together.

Now that I had everything working solid with Exxos's IDE board I went back to the Lightning ST board I want to use in the Mega. The only thing that was different between the two was the wire and single pin I used to insert into pin 20. So I changed the wire and instead of using a single pin I used a row of 10 and soldered to pin that would insert into pin 20 on the socket. Well it now works on all 5 boot images just as Exxos board does so I attribute the issues I had with either the single pin insertion in pin 20 or the clip that connects to the Lightning card. The Lightning works fine with Eprom Emulator. :thumbup: :yay2:

Good news. Thanks for revisiting that.

Yes, the Lightning card is the board of choice for this mega since the netusbee doesn't work in this machine. @cmorley , did take a look at the bad unit again with the microscope and an ohm meter and didn't find anything. Lead pitch is pretty tuff with ohm meter.

Does the machine have an Exxos power supply? NetUSBee doesn't seem to like it.

Yes, it does.. now that you mention it. When its plugged in doesn't even get to xboot...just hangs.

stephen_usher wrote: 10 Feb 2020 16:11 Does the machine have an Exxos power supply? NetUSBee doesn't seem to like it.

Out of curiosity I tried an Atari supply and still no joy with netusbee. Also went back to Exxos's IDE board, I was getting rare random crashes with the Lightning card. So I'm looking to decoding on the EPE card.

Hey everyone. I'm just about to receive a set of two to experiment with on my A1200.

Because of lockdown I only have access to a Mac currently. Is anyone else flashing these with success on a Mac? If so please could you let me know what SmarTTY 3.1 alternative you are using. :D

simon.wilkie wrote: 26 May 2020 11:51 Hey everyone. I'm just about to receive a set of two to experiment with on my A1200.

Because of lockdown I only have access to a Mac currently. Is anyone else flashing these with success on a Mac? If so please could you let me know what SmarTTY 3.1 alternative you are using. :D

Using "Serial" which works great. You can program the device without even plugging it into the computer. Just connect the usb with the device still in the foam.

PaulJ wrote: 26 May 2020 14:44
Using "Serial" which works great. You can program the device without even plugging it into the computer. Just connect the usb with the device still in the foam.

Thanks! I now have a copy of Serial installed and will have a play when the postman calls. :dualthumbup: