Re: Hardware emulation of 6509 using 6502?

From: Michał Pleban <*lists_at_michau.name*> Date: Sun, 25 Feb 2018 22:29:39 +0100 Message-ID: <5A932AC3.2010601@michau.name> · lists_at_michau.name

Hello!

Jim Brain wrote:

> I *think* the problem is that the 6502 has an internally generated set
> of clocks, while the 6509 expects an external clock.  If I look at the
> 6500 datasheet, I see that the PHI1/PHI2 on the 6502 trails the incoming
> PHI0 clock by some amount, but the amount is not defined in the datasheet.
>
> Thus, I think, by feeding the incoming PHI2 clock into the 6502, the
> 6502 delays it internally and thus is running "out of sync" with the
> rest of the bus, which is no doubt synchronized with the external PHI2
> clock on the PCB.

This can be indeed a problem. What is the delay in the 6502? I think the
only solution would be to create a new clock generation circuit.

Regards,
Michau.

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