I am trying to modify an existing data logger that uses a 16c63 and an
AD7890.

The ADC needs an external clock signal to do the conversion which at the
moment is generated in software on a normal output pin. My problem is that
because the signal is generated in software I can't do anything during that
time and I would also like to increase the frequency of the signal to reduce
the conversion time.

The AD7890 has a max frequency of 2.5Mhz and the oscillator driving the PIC
is at 4.9152Mhz, so I can't use the osc. directly.

I would like to have a freq of at least 1Mhz. Am I dreaming or is this
possible preferably without external components as there is no room on the
existing board design.

Peter Graham