Replacing Obsolete micro?

[Rat_Patrol]

Maybe you could use a MC68HC05 clone for a FPGA with the bin dump file https://opencores.org/projects/68hc05

@Wiljan

I'm not a software guy, so could you (or anybody) elaborate on this? Is it the same as an emulator?

[brucehoult]

Maybe you could use a MC68HC05 clone for a FPGA with the bin dump file https://opencores.org/projects/68hc05

@Wiljan

I'm not a software guy, so could you (or anybody) elaborate on this? Is it the same as an emulator?

An FPGA is hardware. You design a hardware logic circuit that does what the original microcontroller does. It's I suppose more of a clone than an emulator. The circuit won't be exactly the same as the original, but maybe somewhere close. You could implement your circuit in 7400 MSI, you could put it in a custom chip. Or you can put it in an FPGA. FPGAs have large numbers of logic gates, flip-flops, SRAM, ALUs. You wire them up according to your design. It's fairly easy to get a modern FPGA to run a CPU at around 50 MHz to 100 MHz, which is a lot faster than ancient micros.

[Wiljan]

Running a soft core CPU in a FPGA means you program the FPGA to have the same logic chip as a CPU does have internally and also the ROM so it can run the program.
Then you have to route the intentional connection to physical pins on the FPGA and have the right voltage levels / clk etc and then the FPGA will do the same as the CPU . It's typical what some people do when the run like "Pacman"  from a Z80 CPU but now in a FPGA https://www.fpgaarcade.com/kb/pacman/

Softcores form many different CPU's are available https://en.wikipedia.org/wiki/Soft_microprocessor
https://opencores.org/projects?expanded=Processor

It might be a solution for you but sure the PFGA will need quite some learning for you if you never used it before

I see the link I gave you for the 68H05 have only VHDL code and have as good as no doc

If you look on the T48 there are much more documentation  sure for a total different processor but the idea is exactly the same
https://opencores.org/projects/t48
https://opencores.org/websvn/filedetails?repname=t48&path=%2Ft48%2Ftrunk%2Fdoc%2FT48+Integration+Manual.pdf

Hope it makes a little sense 

[Rat_Patrol]

Let me see if I understand this properly:

I could take a shelf FPGA, "program" it for the pinout of the obsolete 68 (I understand different footprint, no big deal as I can re-design the PCB to accomodate), and then I can upload the binary/hex to the FPGA and it would act as the obsolete 68?

Surely it is more difficult than it sounds?

[up8051]

It's more difficult because of peripherals (timers, serial interfaces, PWM) and special  ADC.

[Kjelt]

If you are really talking about thousand(s) of boards and product continuation for coming ten years this would IMO be the right time to invest in a new uC and re-design.
What the company did wrong and should now improve on is not using a third party or make good agreements with the 3rd party company such that:
1 there is good documentation , architecture, UML diagrams flowcharts and source code
2 that they own the source code and the software is written in a universal language preferably C or C++
3 aftercare, bugfixes, new features etc.

Do not use a single individual or 1-2 man startup or small company unless you know they have an excellent trackrecord and are well known.
Hire a larger company that has multiple embedded software and hardware people in their services. Here in the vicinity of Eindhoven there are at least 5 of those companies I would entrust it to, so this is not difficult. Make it a fixed price inhouse (their house not your company) project and they have experienced engineers helping new hires and existing people that have no current work on it and thecequipment.

This might be more expensive at first but essential to guarantee point 3 and have a better guarantee that the project will be completed (had my share of experiences with 1 man companies that went belly up or could not deliver in the end what was promised, quality of the software can also be terrible).

[NivagSwerdna]

I have access to the PCB build files, but not the original files for compiling the micro's program, so all I could do is copy the program directly.

Why do you not have access to the originals?  Is this a RE exercise?
It's difficult to suggest an approach without knowing the scale of your problem and the margins?  If it is large then it's a redesign, if it is medium then a port to another similar but available device and if it is small then a hunt for old/compatible parts.
I am suspicious if the only thing is the thing itself... suggests lack of knowledge of function and hence limits the ability to test/verify the next version.

[Rat_Patrol]

I have access to the PCB build files, but not the original files for compiling the micro's program, so all I could do is copy the program directly.

Why do you not have access to the originals?  Is this a RE exercise?
It's difficult to suggest an approach without knowing the scale of your problem and the margins?  If it is large then it's a redesign, if it is medium then a port to another similar but available device and if it is small then a hunt for old/compatible parts.
I am suspicious if the only thing is the thing itself... suggests lack of knowledge of function and hence limits the ability to test/verify the next version.

When the original PCB was ordered, and the company that had the manufacturing contract used a third party to write the software, which is OOB. Apparently, they either didn't get the source files or have lost them. This equipment is 25 years old... Anyway, all I have is the schematic for the PCB itself.

Despite the age, industrial equipment can be kept in service quite a while, and while my customer *needs* about 20 boards, he would like a lifetime supply for himself (for the 100 or boards), and since this equipment is still out there, running up 1-2k and then selling them over probably 5 years could make money on my end.

Perhaps writing all new software would be appropriate, and it probably is, but I'm not sure the juice is worth the squeeze, especially if we can avoid it. The fun part would be figuring out all the communication protocols for all the various conditions. This micro is apparently monitoring various parameters for fault conditions, along with some type of diagnostic tool communications. Yeah, there is external memory involved.

So it is at least partly a RE job, yes.

The simplest approach would just be clone the program onto another micro. The program works fine, the hardware is just aging and failing.

[NivagSwerdna]

To be honest the next step is going to involve detail so that would require a schematic.

Although 68HC05 is obsolete there are devices like MC908GZ16MFAE which might be of interest.  I believe your device is really just a 6800 with a few peripherals (sorry I haven't used that one)... 68HC05 was superceeded by 68HC08?

It's all do-able... just depends on how many hours and $ you want to spend!

[up8051]

Try to disassemble code.
If source code was written in assembler then disassembly result should be clean and easy to interpret