Introduction - If you have any usage issues, please Google them yourself
The ADS7843 is a 12-bit sampling analog-to-digital con-
verter (ADC) used to drive 4-wire touch-screens to serial
interfaces by ratiometrically converting two differential in-
put signals. The ADS7843 also produces an accurate output
with the first conversion cycle once powered up. Because of
this feature, the ADC can be powered up and down continu-
ously, thus, enabling designers to conserve energy in low
power applications such as Personal Digital Assistants (PDA),
where the number of conversions is limited but a fast and
accurate response is required on the first conversion. To
maximize energy conservation, the ADS7843 incorporates a
Pen Interrupt Request feature (PENIRQ), which enables
designers to fully control the power-down operation when
interfacing with Micoprocessors (MPU). Figure 1 is a sim-
plified flow diagram for a PDA showing how PENIRQ is
used to assist in controlling power-down operations.