wm9713 Wolfson Microelectronics plc, wm9713 Datasheet - Page 74

• Manufacturer Part Number: wm9713
• Description: Ac?97 Audio + Touchpanel Codec
• Manufacturer: Wolfson Microelectronics plc

WM9713L
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When operating in co-ordinate mode (COO=1) there will be 3 results to read back from each set of
measurements – namely X,Y and the third additional measurement. After the co-ordinate set has
finished the X result will be present in register 7Ah. Once this has been read back by the user the Y
result will overwrite register 7Ah, as indicated by ADCSRC. Finally, after the Y result has been read
back, the result of the third, additional, measurement will become present in 7Ah, again indicated by
ADCSRC.
To avoid losing data that has not yet been read, the WM9713L can delay overwriting register 7Ah
with new conversions until the old data has been read. This function is enabled using the WAIT bit,
and applies to both single and co-ordinate conversion mode.
The flow diagram in Figure 32 shows the timing of touchpanel conversions, and data readback from
register 7Ah - dependent on the individual settings of the COO, POLL,ADCSEL and CTC bits.
Figure 32 Touchpanel Conversion Flow Diagram
If the SLEN bit is set to ‘1’, then the touchpanel data appears on the AC-Link slot selected by the
SLT control bits, as shown below. The Slot 0 ‘tag’ bit corresponding to the selected time slot is
asserted whenever there is new data on that slot.
ADCSEL (74H)
POLL (74h)
COO (74h)
CTC (74h)
Starts a co-ordinate measurement at specified conversion
Specifies the type of measurement to be made
Starts a single measurement
Enables Co-Ordinate mode
rate
PP Rev 3.2 September 2008
Pre-Production
74