From: Gerrit Heitsch <>
Date: Sun, 24 Jul 2016 06:43:15 +0200
Message-ID: <>
On 07/23/2016 11:56 PM, Segher Boessenkool wrote:
> On Sat, Jul 23, 2016 at 09:21:26PM +0200, Gerrit Heitsch wrote:
>> Forgot that in the last post... There is also the 6510T as used in the
>> 1551 floppy drive. It has the full 8 Bit port. To me the pinout suggests
>> that it's just a different bond out of the 6510:
> Or (more likely imnsho) 8500.

Depends... On the later Chips, MOS included a number to the right of the 
datecode. From what we've been able to determine, if it starts with a 
'1', the Chip is NMOS and if it starts with a '2', the chip is HMOS-II. 
The other numbers are the revision and match the R-number if it's 
present on the chip. I have a few 6510 from after 1986 that have a '16' 
printed there, so they would be NMOS which would suggest the 6510T also 
to be NMOS since it's from 1984.

>>                 _______                 _______
>>           _RES [1  V   ] Phi2     Phi0 [1  V   ] _RES
>>           Phi0 [       ] R/_W    _HALT [       ] Phi2
> This is wrong btw, that #HALT pin is RDY.  Where does that #HALT name
> come from?

Good question, it's been a long time since I wrote that. I'll change it. 
Still means the same though. RDY = HIGH => CPU is running. #HALT = LOW 
=> CPU is stopped.


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