Re: ROM Dump of Amiga Keyboard controller

From: Gerrit Heitsch <gerrit_at_laosinh.s.bawue.de>
Date: Tue, 01 Jul 2014 19:18:55 +0200
Message-ID: <53B2ED7F.6060004@laosinh.s.bawue.de>
On 07/01/2014 08:46 AM, Jim Brain wrote:
> On 6/30/2014 12:17 PM, Gerrit Heitsch wrote:
>> On 06/30/2014 07:13 PM, Gerrit Heitsch wrote:
>>
>>> The byte sequence for that is:
>>>
>>> 78 A9 55 85 83 xx 02
>>
>> Mistake corrected here since SEI is 2 cycles:
>>
>> 78 xx A9 55 85 83 xx 02
>>
>>
>>>
>>> EA EA EA EA EA EA EA EA EA EA 2C 24 EA xx 78 A9 55 85 83 xx 02
>>
>> And here too:
>>
>> EA EA EA EA EA EA EA EA EA EA 2C 24 EA xx 78 xx A9 55 85 83 xx 02
>>
>>
>>  Gerrit
>>
>>
>>
>>
>>       Message was sent through the cbm-hackers mailing list
> No luck so far.  PORT 0x83 always contains 0xfe... :-(
>
> I put the CPU back in the 1520 to ensure I did not roast it.
>
> I checked with the LA, always the same value...
>
> Will tackle more tomorrow.

You made sure you supplied the bytes at half the speed of the clock you 
supplied to the 6500/1? Then there is, of course the question of phase. 
Since the external clock is divided by 2, there are 2 possible phases 
for the resulting clock signal the CPU runs on.

So my idea is to get the external clock stable while keeping _RESET low, 
then have it go to +5V for a moment before going to +10V and start 
supplying the byte sequence.

  Gerrit




       Message was sent through the cbm-hackers mailing list
Received on 2014-07-01 18:00:03

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