AK4650 Datasheet, PDF (49/86 Pages) Asahi Kasei Microsystems – 16Bit ΔΣ CODEC with MIC/HP/SPK-AMP & TSC

[AK4650]
■ Pen Interrupt
The AK4650 has pen interrupt function to detect the pen touch. Pen interrupt function is enabled at power-down state. YN
pin is connected to GND at the PEN interrupt enabled state. And XP pin is pulled up via an internal resistor (Ri), typically
50kΩ. INTN pulled up via an external resistor, 100kΩ, is also connected to XP pin. If the two plates are touched, the
current flows via <TSVDD> – <Ri> – <XP> –<the plates> – <YN>. The resistance of the plate is generally 1kΩ or less,
INTN pin is forced to “L”. If the pen is released, INTN pin returns “H” because two plates are disconnected, and the
current does not flow via two plates.
The operation of INTN pin depends on A2-0 and PINTE bits when PM12AD bit is “1”. If PINTE bit is “1”, INTN pin
goes to “L” when the plate is touched with pen or finger, and goes to “H” when the plate is not touched regardless of the
selection of the analog input channel. If PINTE bit is “0” or 12bit ADC is executed, the operation of INTN pin depends on
the selection of the analog input channel regardless of the touched/non-touched state. If the X-axis or Y-axis is selected as
analog input, INTN pin is forced to “L” regardless of the touched/non-touched state. If VBAT, or auxiliary inputs is
selected, INTN pin is forced to “H” regardless of the touched/non-touched state.
When PM12AD bit is “0”, XP, YP and XN pins go to Hi-Z state at PINTE bit = “0”. At that state, no current flows on
touch screen even if pen is touched. INTN pin is forced to “H” regardless of the touched/non-touched state. If PINTE bit
= “1”, INTN pin goes to “L” when the plate is touched.
PM12AD bit
0
0
1
1
PINTE bit
0
1
0
1
Pen Interrupt
INTN pin Operation
Disable
Always “H”.
Enable
“L” by pen touch, otherwise “H”.
Disable
“L” at XY axis measurement, otherwise “H”.
During measurement:
Auto
“L” at XY axis measurement, otherwise “H”.
After measurement:
“L” by pen touch, otherwise “H”.
Table 42. INTN pin Operation (x: Don’t care)
AK4650
EN1
50kΩ
EN2
Driver OFF
100kΩ
INTN pin
XP pin
Driver ON
YN pin
Figure 37. Pen Interrupt Block Diagram
MS0502-E-01
- 49 -
2007/04