Re: Emulator discrepancies (was DMA'ing in Commodore 64 for developing purposes.)

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Mon, 20 Jun 2022 13:12:12 +0200 Message-ID: <7d9e9b6e-9c5c-1020-330d-7640ccade230_at_laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 6/20/22 12:53, tokafondo_at_tokafondo.name wrote:
> 19 de junio de 2022 21:27, "smf" <smf_at_null.net> escribió:
> 
>> Your device needs to be able to get on and off the bus based on the
>> signals on the port, you can't just use gpio to read it and then pass
>> the data back to the pc and have it then send a command to change it.
>>
>> That part has to be done locally on your device, probably a gal.
>>
>> Do you think you know enough, to be able to implement this? Or is it
>> just a random question?
>>
> 
> 
> On another hand, one thing I realize can't be done is to access the internal registers of the 6510 from outside. AFAIK only the CPU can put its own registers in, or read them back from memory.

Same for the  6Bit I/O-Port on the 6510. Only the CPU itself can read 
and write it.

  Gerrit