68hv11 and 68hc811 Decompiling tool

[Clint]

Can someone point me in the right direction for a good preferably free tool for the disassembly of (specifically 68HC11) and (maybe 68HC811) MCU's

I have tried some dos ones but they are hard to deal with I know a lot about the hardware locations so am hoping I can work out what's going on with this detail.

My ultimate goal is to create a decompiled version that will recompile if that's wasnt obvious, I am not generally hacking I want to add a few features and being 80's hardware the manufacture is long gone.

[legacy]

i used BUFALO directly on bloard, it is a good de-asm

which board do you have ?

[Clint]

No Board I only have the device and a home built simulator for the inputs, so All I have is the bon file of the External ROM.

I was hoping to try and disassemble the file and reassemble it to a working ROM.

[legacy]

have you tried this ?

[Clint]

have you tried this ?

No but it does not mention disassembling?

[G0HZU]

I would use IDA Pro for this.

Even an old version will have support for the 6811. Eg something like Ver 4.3 from 12 years ago.
I don't use IDA Pro as much as I used to but it was easily the best disassembler. Very powerful and you can write your own modules for it if there is an MCU that it doesn't support.

I'd be surprised if there's anything better today but if there is then I'd be interested to see it

[abyrvalg]

What is the nature of your planned extensions? Think - do you really need a full disassembly? In some cases it is easier just to paste a piece of new code into a free space at the end of ROM and patch a couple of jumps/calls to point there. Obtaining a fully reassemblable source is not a trivial task - simple automatic "bin to asm converter" style tools often produce conflicts like data misinterpreted as code and vice versa. If you are still willing to do that - go for IDA Pro as G0HZU advised. IDA is interactive - you can tell it "you are wrong here, these 16 bytes are data".

[Clint]

I really would like a full disassembly, another user came to the rescue with IDA Pro, I will see what I can do in the next week, expect some shouting for help lol !