Identify processor from firmware update image

To me it looks like a CISC processor. The minimum instruction size is

8 bits. An 8-bit relative branch instruction (BEQ or BNE?) is apparently encoded as 0x4E followed by the offset. Having such an instruction points to a smaller processor, maybe comparable to 6502 or Z80 (but not exactly them).

Thanks for taking the time. How did you deduct the relative branch instruction code?

This recording device operates on sample rate of 44100 Hz, with 16 bits per sample. It can decode and encode MP3. It is capable of realtime sound processing with several filters applied. Some of the source code filenames mentioned in firmware suggest that these DSP algorithms are all executed on the same processor: dsp_bg121.cpp edt_ifx_dly.cpp (delay effect) edt_ifx_trm.cpp (tremolo effect) edt_ifx_flg.cpp (flanger effect)

So, either it is a processor with considerable more power than Z80 and

6502, or they're using some kind of 8-bit uC / DSP hybrid. Perhaps you could give me few pointers to find more info from firmware image?

Thanks Josip

Most likely an ASSP. Some Asian companies e.g. Sonix sell VERY cheap DSPs, with an 8-bit controller core and a "sidecar" DSP.

I guess so. I'll try to disassemble the unit and check chip markings, but my hopes are not very high.

Thanks Josip