AK4533 Datasheet, PDF (30/40 Pages) Asahi Kasei Microsystems – Audio Codec with Touch Screen Controller

[ASAHI KASEI]
The interface of touch screen controller block shares with audio control interface. (For the detail of read/write
sequence, please see "Figure 12. Audio/Touch Screen Control Interface Timing")
„ Touch Screen Control Register
Addr
D7
D6
D5
D4
D3
D2
D1
D0 Default
07 Touch Screen Control
TSPD
PW
X
X
D3
D2
D1
D0
80
Table 7. Touch Screen Control Register
D3:D0 Selection of Input Channel/Output Channel
Table 8 describes the relationship between D3:D0 bits and the states of TSX_TOP, TSX_BTM, TSY_TOP, TSY_BTM,
AIN, and VREF.
As TSX_TOP, TSX_BTM, TSY_TOP, and TSY_BTM can output one of the three voltage level, VA, AGND, and Hi-Z
by the combination of D3:D0 bits, touch screen control block is very flexible. For example, there are two ways to
measure the x-axis spot as No.1 configuration or No.2 configuration in Table 8.
Touch Screen
Control Register(07h)
The State of Touch Screen
Terminals
Analog
Input
VREF
Input
No D7 D6 D3 D2 D1 D0 TSX_
. ^{(TSPD) (PW)}
TOP
TSX_
BTM
TSY_ TSY_
TOP BTM
AIN
VREF Note
0
0
0
0 000
VA
AGND OPEN OPEN TSY_TOP
VA
X-axis Measurement
1
0
0
0 0 0 1 AGND
VA
OPEN OPEN TSY_TOP
VA
X-axis Measurement
2
0
0
0 0 1 0 OPEN OPEN
VA AGND TSX_TOP
VA
Y-axis Measurement
3
0
0
0 0 1 1 OPEN OPEN AGND VA TSX_TOP
VA
Y-axis Measurement
4
0
0
0 1 0 0 AGND OPEN AGND OPEN
X
VA
Discharge
5
0
0
0 1 0 1 OPEN OPEN OPEN OPEN
X
VA
6
0
0
0 1 1 0 AGND AGND OPEN OPEN
X
VA
Discharge
7
0
0
0 1 1 1 OPEN OPEN AGND AGND
X
VA
Discharge
8
0
0
1 X X 0 OPEN OPEN OPEN OPEN
BTI_1 TPVREFIN Battery Measurement
9
0
0
1 X X 1 OPEN OPEN OPEN OPEN
BTI_2 TPVREFIN Battery Measurement
10 0
11 0
12 1
13 1
1
1 X X 0 OPEN AGND_R OPEN VA
BTI_1 TPVREFIN Pen Waiting &
Battery Measurement
1
1 X X 1 OPEN AGND_R OPEN VA
BTI_2 TPVREFIN Pen Waiting &
Battery Measurement
1
X X X X OPEN AGND_R OPEN VA
X
X
Pen Waiting &
Power Down State
0
X X X X OPEN OPEN OPEN OPEN
X
X
Power Down State
(Default)
VA
AGND
OPEN
BTI_1,BTI_2
TPVREFIN
AGND_R
Power Supply Voltage
Analog Ground
Hi-Z state
Measurement of Buttery Voltage
External Reference Voltage
TSX_BTM is connected to AGND through internal resistor.
Table 8. The relationship between input/output channel and D3:D0 bits
<Revision 0.9a>
29
July 00