Re: commodore superpet mapping

From: didier derny <didier_at_aida.org>
Date: Tue, 1 Nov 2016 21:38:57 +0100
Message-ID: <48445c2c-7326-3426-45ec-b557647e34d6@aida.org>
thanks André, really interesting....


On 01/11/2016 15:45, André Fachat wrote:
> You may want to have a look at 
> http://www.6502.org/users/andre/petindex/superpet.html
>
> Regards,
> André
>
>
> Am 1. November 2016 14:26:08 schrieb Rhialto <rhialto@falu.nl>:
>
>> On Tue 01 Nov 2016 at 13:53:03 +0100, didier derny wrote:
>>> if I saw this machine in 1981, I never really had the opportunity to
>>> play with it
>>> Initially I thought the 6809 was running on it's ram and communicating
>>> with the 6502...
>>> (a bit like the madison zram with it's z80)
>>>
>>> recently I found the schematics of the superpet board (combined one)
>>> Finally  (apparently according what I saw)
>>> 1/  either the  6809  or the 6502 is running ?
>>
>> Yes, only one at a time.
>>
>>>       6809 stopped by the dma   ?
>>
>> There is a hardware switch which usually controls which cpu runs. The
>> changeover actually happens during RESET, if I remember well. Although
>> there is also a setting on the switch to control it by software.
>> However that isn't implemented in VICE I think. I haven't seen any
>> software which uses it, so there is no info coming from that direction.
>>
>>>       6502 stopped by shutting down the power  ?
>>> 2/ the extra memory is only accessed as 16 page s of 4k in 9000 ?
>>
>> Yes.
>>
>>> 3/ it add a serial port
>>>
>>> 4/ a protection dongle
>>
>> The 6702, which was reverse engineered by this mailinglist and me.
>>
>>> Initially I thought the 6809 was running on it's ram and communicating
>>> with the 6502...
>>>
>>> how are the rom decoded ?  I dont really understand...
>>> the standard rom are only 'seen' by the 6502 ?
>>> the extra rom only 'seen' by the 6809 ? and mapped at the same place ?
>>
>> Yes, each CPU sees only its own ROMs even though they are mapped to the
>> same address range.
>>
>> You can play with it in VICE, select the SuperPET model, and find the
>> Waterloo software disk images. The 6809 is not emulated cycle-exact, but
>> it is fairly close and apparently good enough for the normal SuperPET
>> software.
>>
>>> didier
>> -Olaf.
>> -- 
>> ___ Olaf 'Rhialto' Seibert  -- Wayland: Those who don't understand X
>> \X/ rhialto/at/xs4all.nl    -- are condemned to reinvent it. Poorly.
>
>
>
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Received on 2016-11-01 21:00:02

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