It is.I'm going to guess a PROM of some kind, whatever BD01/02/04 are - since the slot is marked BD03
I'd love to check the other proms but they're illegible . My board looks to have lead a rough life prior to my owning it.Is it confirmed to be a 82S123?I converted the MAME dump to equations and I can see data only on four outputs (while the 82S123 had eight of them) so in my opinion it's a 82S129 which, indeed, has four outputs.Can you check, please, the type of the other BPROMs on your board?
Well, after testing we will know if it has other issues or not!Thanks for picture.Confirmed, all the BPROMs are Fujitsu MB7114 (256 x 4-bit) compatible with Signetics 82S129 and other.My GAL recreation should work as replacement of the missing one but testing on PCB will give us the definitive answer (unless the board has other issues)
My bad Caius, I misread the ref (not easy with the BD 0x marking on top of it). I can confirm it's a 82S129.Is it confirmed to be a 82S123?I converted the MAME dump to equations and I can see data only on four outputs (while the 82S123 had eight of them) so in my opinion it's a 82S129 which, indeed, has four outputs.Can you check, please, the type of the other BPROMs on your board?
Thanks but let's wait for the testing on PCB.My bad Caius, I misread the ref (not easy with the BD 0x marking on top of it). I can confirm it's a 82S129.Good job on the GAL replacement!
It can only but work. It can be seen as a table with 8 inputs and 4 outputs.Thanks but let's wait for the testing on PCB.My bad Caius, I misread the ref (not easy with the BD 0x marking on top of it). I can confirm it's a 82S129.Good job on the GAL replacement!
Correct.If the /CE lines are tied to GND then no problem, pins can also be omitted in equations.But if they receive a signal, then we have to declare OE equations for each ouput.So, @rewrite can you check if pin 14 and 15 of the socket of the missing BPROM are tied to GND?It can only but work. It can be seen as a table with 8 inputs and 4 outputs.Only /CE signals can be problematic.Thanks but let's wait for the testing on PCB.My bad Caius, I misread the ref (not easy with the BD 0x marking on top of it). I can confirm it's a 82S129.Good job on the GAL replacement!
In my experience, if the /CE lines are permanently tied to GND, you can ignore them when you declare I/O in equations, it will work the same.But if they get toggling signals, then you have to declare something like this as inputs :Even if only one of the /CE signal is tied to ground or if both pins are tied together it should work if you use the /OE pin of the GAL and the .OE syntax in the equations.
This way you can drive 3 state outputs (but pinout doesn't match for the /OE and /CE signals).
Forgive me, because I'm still new at this, but I'm really trying to learn. Tied to GND would mean it has continuity with the GND on the JAMMA edge, right? I just don't want to give the wrong answer because I misunderstood the terminology.Correct.If the /CE lines are tied to GND then no problem, pins can also be omitted in equations.But if they receive a signal, then we have to declare OE equations for each ouput.So, @rewrite can you check if pin 14 and 15 of the socket of the missing BPROM are tied to GND?It can only but work. It can be seen as a table with 8 inputs and 4 outputs.Only /CE signals can be problematic.Thanks but let's wait for the testing on PCB.My bad Caius, I misread the ref (not easy with the BD 0x marking on top of it). I can confirm it's a 82S129.Good job on the GAL replacement!
What I wanted to say is it's still possible to have 3 state outputs if one of the /CE lines isn't tied to ground our if both are connected together to something different to ground.In my experience, if the /CE lines are permanently tied to GND, you can ignore them when you declare I/O in equations, it will work the same.But if they get toggling signals, then you have to declare something like this as inputs :
PIN 17 = CE1
PIN 18 = CE2
and like this (for each output)
D0.oe = !CE1 & !CE2;
What about pin 13 (/CE1)?Forgive me, because I'm still new at this, but I'm really trying to learn. Tied to GND would mean it has continuity with the GND on the JAMMA edge, right? I just don't want to give the wrong answer because I misunderstood the terminology.
If so, then Pin 14 (CE2 according to the pinout of 82S129) is tied to GND, and 15 (A7) is not.
13 is not.What about pin 13 (/CE1)?