At 08:21 AM 2/27/2004 -0800, you wrote:


>No, because I can drive it fine if I either hard ground it, or drive it from
>portD, so the wiring is correct.  Just seems that portB can't sink it
>enough?

Okay, Are you accessing portB very soon (like the next few instructions)
after writing the 0? The MOSFET gate has  a *lot* of capacitance (and it's
not specified). If you do a RMW  (for example, bsf PORTB,0) instruction
to PORTB too soon after writing a "0" to RB4, it will get reset to
high. It has to have time to pull the port pin to below ~400mV to be safe.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

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