AK4673 Datasheet, PDF (77/107 Pages) Asahi Kasei Microsystems – Stereo CODEC with MIC/HP-AMP and Touch Screen Controller

[AK4673]
■ WRITE Operation Sequence
The selection of channel input of the AK4673 is determined by a command byte. When accelerate command (A2= “0”) is
sent, the switch on timing of the driver switch is 18^th falling edge of SCL regardless of PD0 bit. The accelerate command
is to accelerate the timing of desired driver SW ON to ensure that AK4673 needs more settling time. Actually sampling
timing is on the time of READ operation, it is possible to take settling time longer even when the impedance of the touch
screen is large.
SCL
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
SDA
Address Byte
Command Byte
R/ W
100
1
0
0 CAD0 0
0
S A2
A1 A0 X1 PD0 MODE X2
0
START
Touch Driver SW
A2=0, PD0=0 or 1
A2=1, PD0=1
AK4673
ACK
AK4673
ACK _STOP
A2=1, PD0=0
I
II
III
IV
Figure 74 write operation and Driver SW timing
■ READ Operation Sequence
A/D conversion is synchronized with SCL. Sampling time is the one SCL clock period (SCL7↓∼ SCL8↓) on the end of
writing address byte and then hold. A/D conversion is held on the next 12 SCL period (except MASTER ACK). After
address byte is sent, the readout sequence starts with an acknowledge, which is the responce of the AK4673 when the
address maches. The MSB data byte will follow (D11∼D4) then issued acknowledge by master. The LSB data byte
(D3∼D0, followed four “0”) will be followed by NOT acknowledge bit (NACK) from master in order to terminate the
read transfer. The master will then issued STOP that ends read operation or Repeated Start condition that keeps write or
read operation. The master will issue Repeated Start Condition or START condition followed by read operation again.
AK4673 repeats A/D data updated [continuous read operation]. Master must issue STOP condition after terminating the
last read out of A/D data.
SCL
SDA
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
R/ W
100
1
0
0 ^CAD0 1
0 ^{D11 D10 D9}
D8 D7 D6 D5 D4
0 D3 D2 D1
D0
0
0
0
0
1
START
Address Byte
AK4673
ACK
Data Byte (MSB)
MASTER
ACK
Data Byte (LSB)
MASTER
NACK _{STOP or}
Repeated START
Touch Driver SW
A2=“0” or A2=“1” , PD0=“1”
Sampling
“H”
AD conversion
A2=“0”, PD0=“0”
A2=“1”, PD0=“0”
IV
MS0670-E-00
V
Figure 75 Read data Sequence
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2007/09