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Re: New project: An ACT Apricot F1 "barn find"
Posted: 22 Sep 2021 12:56
by stephen_usher
rubber_jonnie wrote: 22 Sep 2021 12:01
Well at least you have them now. Is the built one complete or is there more for you to do to it?
It merely needs the through-the-hole pins installed to make the DIP package.
Re: New project: An ACT Apricot F1 "barn find"
Posted: 22 Sep 2021 13:02
by rubber_jonnie
stephen_usher wrote: 22 Sep 2021 12:56
rubber_jonnie wrote: 22 Sep 2021 12:01
Well at least you have them now. Is the built one complete or is there more for you to do to it?
It merely needs the through-the-hole pins installed to make the DIP package.
Sounds good :)
Re: New project: An ACT Apricot F1 "barn find"
Posted: 23 Sep 2021 08:30
by stephen_usher
I just had a chance to try a dry fit of the 8 pint DIN socket on a board and... It fits nicely. Woot! Well, that's one win anyway. My new footprint is correct.
Re: New project: An ACT Apricot F1 "barn find"
Posted: 24 Sep 2021 10:20
by stephen_usher
It looks like the memory PCBs (one pre-built) are arriving today. That should make building the first board easier as I don't have to worry about my surface mount soldering ability.
Re: New project: An ACT Apricot F1 "barn find"
Posted: 25 Sep 2021 19:56
by stephen_usher
The new board is made up...
IMG_2411.jpg
Will it work??????? :D
Re: New project: An ACT Apricot F1 "barn find"
Posted: 25 Sep 2021 20:36
by stephen_usher
Erm... No.
The machine does boot. There is no smoke but it doesn't see the RAM. I'm going to have to solder pins to the expansion connector and get the logic analyser out.
At least the RGB connector works! :-)
P.S. Due to other things I have to do I'll have to leave this until at least Monday now.
Re: New project: An ACT Apricot F1 "barn find"
Posted: 25 Sep 2021 20:54
by stephen_usher
Oh, the output from the SRAM chip doesn't look very good. On some data lines on read it hardly pulls the data line down at all. I wonder if PCBWay half killed the chip whilst they were soldering it on the daughter board.
Re: New project: An ACT Apricot F1 "barn find"
Posted: 26 Sep 2021 10:44
by stephen_usher
OK. This is interesting...
I ran my memory test program on the new board and it can write and read from memory correctly it seems, however the BIOS is reporting a memory test failure (error 25).
Re: New project: An ACT Apricot F1 "barn find"
Posted: 26 Sep 2021 11:13
by stephen_usher
OK. It's not an addressing issue or a byte reading issue as I've modified my memory test program to XOR the segment address with the address offset which I'm writing to memory and that passes. I've also changed the program so that it writes as whole words but then reads as bytes and that works.
It must be some sort of timing issue, but the GAL code for this hasn't really changed.
Re: New project: An ACT Apricot F1 "barn find"
Posted: 26 Sep 2021 11:28
by stephen_usher
And now it's not seeing the board at all.
I'd better reflow the solder *everywhere*.
The previous board still works fine, so the system's OK.