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BillO
PostPosted: Tue Feb 25, 2020 12:15 am 
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Just wondering why WDC did not bring WAIT out to pin 35. It seems to me that would have been a keen idea. I realize that using a W65C02S in a legacy system it is never likely to execute a WAI instruction, so having the WAIT output on the RDY line is no biggie ... but, there is pin 35 ... all lonely and feeling no love. Kinda sad, no?

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BigDumbDinosaur
PostPosted: Tue Feb 25, 2020 2:49 am 
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BillO wrote:
Just wondering why WDC did not bring WAIT out to pin 35. It seems to me that would have been a keen idea. I realize that using a W65C02S in a legacy system it is never likely to execute a WAI instruction, so having the WAIT output on the RDY line is no biggie ... but, there is pin 35 ... all lonely and feeling no love. Kinda sad, no?

A corollary question is why didn't WDC make the 65C816 available in a PLCC-52 package? If they did there would be sufficient pins to separate A16-A23 from the data bus, eliminating that multiplexing mess.

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Michael
PostPosted: Tue Feb 25, 2020 3:12 am 
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BillO wrote:
Just wondering why WDC did not bring WAIT out to pin 35. It seems to me that would have been a keen idea. I realize that using a W65C02S in a legacy system it is never likely to execute a WAI instruction, so having the WAIT output on the RDY line is no biggie ... but, there is pin 35 ... all lonely and feeling no love. Kinda sad, no?
Personally, I'm very thankful the designers left pin 35 available as a "No Connection".

Cheerful regards...


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6502 64K Socket.png
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Chromatix
PostPosted: Tue Feb 25, 2020 4:16 am 
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Pin 35 is not completely unused on the 6502 family. I think on the 'C102 it's part of the 4x clock generator. The Phi1 (now actually Phi4) and Phi2 outputs are then no longer in their usual relationships with the Phi0 input. So I imagine WDC left it available in case they got a custom order for a modern run of the 'C102.
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Martin_H
PostPosted: Tue Feb 25, 2020 5:46 pm 
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@Michael, that 65c02 socket project looks interesting. Do you have a separate project thread about it?
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Michael
PostPosted: Fri Feb 28, 2020 2:06 pm 
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Martin_H wrote:
@Michael, that 65c02 socket project looks interesting. Do you have a separate project thread about it?
Not yet. Sorry. Work-In-Progress.


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BigEd
PostPosted: Fri Feb 28, 2020 2:09 pm 
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Work in progress threads are highly acceptable!
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