Re: Hardware emulation of 6509 using 6502?

From: Jim Brain <brain_at_jbrain.com>
Date: Sun, 25 Feb 2018 13:46:20 -0600
Message-ID: <50f83924-2b6c-ef1c-ca8a-e2013cc03905@jbrain.com>
On 2/25/2018 1:19 PM, Mia Magnusson wrote:
> The simple solution is to set the page outputs to 14 / $E or any other
> unused bank (which tristates the data bus) while reading/writing $0/$1.
>
> As the CPLD anyway can output whatever it wants on the page outputs,
> and as it anyway can detect access to adress 0/1, this should not
> require any additional hardware as long as there is room in the CPLD
> for the extra equations.
There is.  And, thanks for the quick short term solution.  In a future 
rev of the board, I can pass the data lines through the CPLD, but this 
one does not have that.

Currently, I think there are other problems, but I will respond with 
those in a different email.

Jim

-- 
Jim Brain
brain@jbrain.com
www.jbrain.com


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Received on 2018-02-25 21:03:27

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