Re: Hardware emulation of 6509 using 6502?

From: Jim Brain <brain_at_jbrain.com>
Date: Fri, 6 Jul 2018 12:50:53 -0500
Message-ID: <ab51ae63-18d4-88a7-9347-16bc3bdcb741@jbrain.com>
On 7/6/2018 4:54 AM, Michał Pleban wrote:
> Jim Brain wrote:
>
>> It looks like the test is not failing in the same spot all the time.  It
>> looks like a transient error.  Any chance to extend your program to do a
>> bunch of write and reads and report any issues?  It would help to see if
>> there is a stuck bit or something else.
> Transient errors are hardest to debug... But I presume you made a trace
> then, can you show it?
Yes, and no.  It is easier to set up the 8 port PC-based LA, so I added 
code in the CPLD to activate a pin when the address was reached, and 
then traced it and the port values and a signal indicating whether the 
port was showing the $0 or $1 value.  I see that sometimes, the port 
changes to #$1 a number of times, and then it shows your address.  The 
number of tests varies.

>
> I can extend the test to read or write a value several times (or to
> repeat the whole test XX times in a row), but a live trace from the
> KERNAL will be the best starting point.
I don't have a way (that I know of ) to grab data from the HP 1650B (I 
usually take photos, so old skool).
>
> Regards,
> Michau.
>
>

-- 
Jim Brain
brain@jbrain.com
www.jbrain.com
Received on 2018-07-06 20:02:22

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