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BitBrain's avatar
BitBrain
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2 years ago

State Machine Controller for SOC FPGA/PLD

Long ago, I met an engineer that stated they had the license from Intel to modify the microcode. Using this, would it be possible to use Intel microcode for a RISC processor, to run / control the des...
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BitBrain's avatar
BitBrain
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2 years ago
Aliff, Thanks for your support. In early 1980's, I worked with engineers who developed microcode for AMD bit-slice processors. The program was loaded into RAM for execution by the slice processors. The engineer I met claiming to use Intel microcode was from Mitre or MitreTek in Northern Virginia. That was in the 1990's. So, I'm thinking Intel microcode can be loaded into a RAM based state machine that controls FPGA's/PLD for various applications. Let's say the application is to make a very fast numerical engine or 1M point FFT that might have 1024 long data. Just a guess on something that's not need done. In the 1980's we did it for a speech processor and image processor using LPC microcode on AMD 2900.
_AK6DN_'s avatar
_AK6DN_
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2 years ago

"So, I'm thinking Intel microcode can be loaded into a RAM based state machine that controls FPGA's/PLD for various applications."

BitBrain, your misunderstanding is that there is a single thing that is "Intel microcode". There is not.

A microcode program is no different than any other software program. It is a sequence of instructions
that is implemented on some processor architecture that is designed to accomplish some task.

Running a microcode program from a writable control store on a custom bit slice processor implementation
is fundamentally no different than running an X86 instruction set program on your Windows PC. Or running an ARM
instruction set program on a new Apple Mx series computer.

Different program implementation languages and different processor architectures but not conceptually different.

So it appears back in the 90s some hardware engineer designed a custom AMD (probably AM2900 series) bit slice
processor datapath architecture and then a microcode engineer / programmer write some (micro)code to program
it and implement some functionality.

Conceptually you could do that now given a large enough FPGA. Implement AM2901 4b datapath slices in verilog.
Combine them together with other datapath entities (register files, etc) and a microsequencer. Add in some RAM
modules to provide a writable control store for your microcode program. And then write some microcode to do it.