How to write protect PAL's?

[Doomguy42]

Hi,
A friend and I are reproducing some old Pal chips for some arcade remake boards. The chips are palce16v8h family. When programming does anyone know how we write protect them?
Can anyone help with this?
Thanks

 

[rjenkinsgb]

They are only programmable while in a PAL programmer that can supply the high programming voltage [eg. 15V] needed to put them in that mode.

Once in a normal 5V circuit, they can never change to programming mode.

There is a read-protect config bit that can be set to prevent copying; once that is on it can only be cleared by a whole chip erase cycle.

 

[Pommie]

I can't remember that far back. Last time I used a pal was late 80s, early 90s.

What arcade game is it?

Mike.

 

[gophert]

I can't remember that far back. Last time I used a pal was late 80s, early 90s.

What arcade game is it?

Mike.

Or... which missile guidance system is it?

 

[Nigel Goodwin]

Or... which missile guidance system is it?

Funnily enough, an old friend of mine (who I've not seen for years) used to write software for guided missiles

 

[Doomguy42]

Guided missiles would have they're own special write protecting system!?
Yup it's a 94 era tech we are working on... we have an appropriate programmer and our repro chips are successfully accepting the logic programs and working fine in our new boards.
It's taken along time and a lot of work so ideally we'd like to write protect them but can't seem to work out how to do it or where the security 'bit is? I was just wondering if anyone can help?

 

[Nigel Goodwin]

Guided missiles would have they're own special write protecting system!?
Yup it's a 94 era tech we are working on... we have an appropriate programmer and our repro chips are successfully accepting the logic programs and working fine in our new boards.
It's taken along time and a lot of work so ideally we'd like to write protect them but can't seem to work out how to do it or where the security 'bit is? I was just wondering if anyone can help?

As already mentioned, you don't 'write protect' them (what good would that do?), you 'read protect' so they can't be copied by any third party.

 

[Doomguy42]

Yes that's what we want to do... apologies for the incorrect terminology. Any ideas on how to 'read protect' the programs?

 

[rjenkinsgb]

Any ideas on how to 'read protect' the programs?

It's in the data sheet - the "security bit", mentioned on Page 7:

https://www.latticesemi.com/-/media/LatticeSemi/Documents/DataSheets/PAL/PALCE16V8PALCE16V8ZDataSheet.ashx?la=en

If I remember correctly, it's usually an option to set that or not, in whatever programming tool you are using.

 

[Doomguy42]

Thanks very much! We had looked at that but couldn't find an option on the programmer maybe it's in the program itself.

 

[ronsimpson]

We had looked at that but couldn't find an option on the programmer maybe it's in the program itself.

My computer outputs a file that I can see with a text editor. (or is it a HEX editor) If you know the location and bit then just go in by hand and change the bit.