How to delay the BE going high after reset.

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cheekyfox
Posts: 19
Joined: 20 Mar 2010
Location: Germany

How to delay the BE going high after reset.

Post by cheekyfox »

Need help, need to delay the BE going high by at least 200nS after the RES line goes high. This is to force the W65C134 to use the external ROM from the start. I have proved that this works with using a pushbutton to hold the BE low till after the reset.

Any suggestions would be welcome.

I have attached the schematic for the W65C134SXB board that I am using.
W65C134SXB.pdf
W65C134SXB Schematic
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gfoot
Posts: 871
Joined: 09 Jul 2021

Re: How to delay the BE going high after reset.

Post by gfoot »

You could just use something like a DS1318 to hold it low, it will do so for quite a while though (100ms or more, I think).

You can also use an RC circuit through a Schmitt trigger to wait about the right amount of time.

Or feed your clock signal through a counter to count the right number of clock cycles for your delay.
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