Trying to get a Godil powered Atom alive

discussion of games, software, hardware & emulators relating to the Acorn Atom and Acorn System machines.
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bprosman
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Trying to get a Godil powered Atom alive

Post by bprosman » Mon Dec 03, 2018 11:06 pm

Tonight I tried to get my "Godil powered" Atom alive (with Dave Hoglet's T65) unfortunately it doesnt work (yet). Hope that with help of some people here I can get it alive so that I can use the T65 for a stubborn Junior Computer (Elektor) as well.

My starting point is a "bare minimum Atom" which runs fine with the processor in, which works well :
IMG_7681.JPG
IMG_7682.JPG
As my Chinese Xilinx programmer only had a connector with a 2.54mm pitch I had to make a little convertor board :
IMG_7686.JPG
Programming went well and the Godil responds on the serial port :
IMG_7679.JPG
IMG_7683.JPG
Unfortunately the Atom doesnt start, also not after closing the "Break" key :
IMG_7684.JPG
The Godil with my self-made adapter has been tested for continuity, that is ok. I checked it against a Godil I had from Roland (the placement of the 40 pin socket) and pin 1 of the 40 pin DIL socket is pin 3 of the Godil etc.

Hope we can get this to work.
Kind regards, Bram
Last edited by bprosman on Mon Dec 03, 2018 11:47 pm, edited 2 times in total.

bprosman
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Re: Trying to get a Godil powered Atom alive

Post by bprosman » Mon Dec 03, 2018 11:31 pm

Tried a X250 version (original DIL socket Godil, with 250 Image) same result.
"Reset" command gives the same with the 250 and 500 version :
IMG_7685.JPG

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hoglet
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Re: Trying to get a Godil powered Atom alive

Post by hoglet » Tue Dec 04, 2018 7:07 am

Edit: Skip to next post for the answer....

Why not single step and see how far it gets?

The manual is here:
https://github.com/hoglet67/AtomBusMon/ ... -Reference

The following commands would reset then step for 10,000 instructions, logging each:

Code: Select all

reset
s 10000
Configure your terminal to log all the output.

Try that and see where you get to.

Dave
Last edited by hoglet on Tue Dec 04, 2018 7:26 am, edited 2 times in total.

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hoglet
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Re: Trying to get a Godil powered Atom alive

Post by hoglet » Tue Dec 04, 2018 7:10 am

OK, I just looked more closely at your first screen shot. It's getting to FF13 then looping.

This is to do with the 6522:

Code: Select all

FF10  2C 01 B8  BIT #B801       Busy ?
FF13  30 FB     BMI #FF10       ..yes, wait for printer to be not busy
Try temporarily removing the 6522.

Edit: Ah, I see the 6522 is not fitted. The problem is the pull downs on D1..3 are 4.7K, but the pullups in the GODIL are only 1.5K. So they are cancelling out the pulldowns. This makes the Atom think the 6522 is present when it isn't.

The easiest solution is to fit the 6522.

FYI: This problem wouldn't happen with the new active level shifter. It's a good example of why I don't like the type of level shifter used by the GODIL.

Dave
Last edited by hoglet on Tue Dec 04, 2018 7:27 am, edited 3 times in total.

bprosman
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Re: Trying to get a Godil powered Atom alive

Post by bprosman » Tue Dec 04, 2018 8:01 am

Is that a hint to get that finished as well Dave ? 😃😃😃😃😃

bprosman
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Re: Trying to get a Godil powered Atom alive

Post by bprosman » Tue Dec 04, 2018 10:45 am

And we have a lift-off :D
So my simple adapter board is confirmed to work.
Thanks for all your help and patience Dave, next stage EE-Pizza and real level shifters.
IMG_7687.JPG
IMG_7688.JPG

bprosman
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Re: Trying to get a Godil powered Atom alive

Post by bprosman » Tue Dec 04, 2018 4:01 pm

Final bit, some text to recognize the direction. Some cover to avoid "bits falling in" where the connector pins are still (sort of) accessible.
IMG_7698.JPG
Net step, a similar Z80 version and Dave "Hoglet"'s level shifter board to get this to work with the "EE_Pizza" board as well.

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