Hello I'm trying identify old RICOH RF5A93 uC. Cannot find any info in the net. This is exteral memory QFP100 chip, at least 1998 year of production. I downloaded code but this instruction set is new to me and still don't know what it is. I wrote simple program to count which bytes are most popular and this is what I got: 1/ 0xE0 2/ 0x08 3/ 0x0A 4/ 0x0B 5/ 0x10 6/ 0x01 7/ 0x0C 8/ 0x0E 9/ 0x90 10/ 0x02 Can anyone can help me identify this code?
Ricoh did both 6502 and 65816 CPUs. In your case I would check WDC 65C816 for more details.
Eberhard H. wrote: > Ricoh did both 6502 and 65816 CPUs. > In your case I would check WDC 65C816 for more details. Unfortunately both CPUs use 6502 opcodes, so I'd expect 0xA9 (LDA) or 0x4C (JMP) would be some of the most popular hex codes...
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Edited by User
A list of "most popular bytes" is not very helpful to identify a CPU. Better would be a longer sequence of real code to be disassembled. I still believe that it is a 65816 core.
It is rather not WDC 65C816. I found it was used in older chips like RICOH 5A22, but it seems they are changed to newer architecture in 1998. Probably it is something like V8xx but still don't know which extension, because in V8xx there are multiple instruction sets... But code look similiar (there is a lot of low codes <0x0F). Sequence 0xE01x is very popular and looks like jump for me (relative jump?), while there is almost no 0xE1 opcodes. Code starts with: 0xFCE0180B140E07E0100B14200804E089
What I understand now that sequence is probably 32b long, so it can be opcode and relative address bits dispersed in last 3 bytes, like: 0b11100000, 0b0001xxxx, 0b0000xxxx, 0bxxxxxxxx where x - relative address bits I uploaded whole code here: http://geocities.ws/hf8v/hf/resources/MM-089.ZIP Here is RF5A93 pinning: http://geocities.ws/hf8v/hf/resources/RF5A93.TXT HF-17612 project site is here: http://geocities.ws/hf8v/hf/hf17612.htm
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