
[AK4671] 
MS0666-E-00 
2007/10 
- 114 - 
■
 Serial Control Interface 
(1) 4-wire Serial Control Mode (I2C pin = “L”) 
Internal registers may be written by using the 4-wire μP interface pins (CSN, CCLK, CDTI and CDTO). 
In case except for 10bit SAR ADC data read, the data on this interface consists of a 3-bit Chip address (fixed to “100”), 
Read/Write (1bit), Register address (MSB first, 7bits) and Control data (MSB first, 8bits). 
In case of 10bit SAR ADC data read, the data on this interface consists of a 3-bit Chip address (fixed to “101”), 
Read/Write (1bit: fixed to “0”) and SAR ADC Data (MSB first, 10bits). 
Address and data is clocked in on the rising edge of CCLK and data is clocked out on the falling edge. Address and data 
are latched on the 24th CCLK rising edge (“
↑
”) after CSN falling edge (“
↓
”) for write operations and CDTO bit goes to 
Hi-Z after CSN rising edge (“
↑
”). CSN should be set to “H” once after 24th CCLK for each address. The clock speed of 
CCLK is 5MHz (max). The value of internal registers is initialized at PDN pin = “L”.  
CSN
CDTI 
CCLK
C2 
0 
1 
2 
3 
4
5
6
7
16
17 
18 
19 20 
21 
22
23
D4 
D5 
D6 
D7
0
0
0
C0 
R/W 
C1 
0
D0
D1
D2 
D3 
CDTO 
Hi-Z 
WRITE 
CDTI 
C2 
D4 
D5 
D6 
D7
0
0
0
C0 
R/W 
C1 
0
D0
D1
D2 
D3 
CDTO 
Hi-Z 
READ 
(except for  
10bit SAR ADC Data) 
D4 
D5 
D6 
D7
D0
D1
D2 
D3 
Hi-Z 
0
8
9
10
11
12
13
14
15
A1
A2
A3
A4
A5
A6
A0
0
A1
A2
A3
A4
A5
A6
A0
Clock,  
"H" or "L"
Clock, 
"H" or "L"
"H" or "L"
"H" or "L"
"H" or "L"
"H" or "L"
C2-C0: Chip Address (Fixed to “100”) 
R/W: READ/WRITE (0: READ, 1: WRITE) 
A6-A0: Register Address 
D7-D0: Control Data 
Figure 96. Serial Control I/F Timing (Except for 10bit SAR ADC Data) 
CCLK
CSN
0 
1 
2 
3 
4
5
6
7
16
17 18 19 20 21 22
23
8
9
10
11
12
13
14
15
CDTI 
C2 
D4 
D5 
D6 
D7
0
0
0
C0 
R/W 
C1 
0
D0
D1
D2 
D3 
CDTO 
Hi-Z 
READ 
(10bit SAR ADC Data) 
0 
0 
D0 
D1
0
0
0 
0 
Hi-Z 
D6
D7
D8
D9
D2
D3
D4
D5
Clock,  
"H" or "L"
"H" or "L"
Clock, 
"H" or "L"
"H" or "L"
C2-C0: Chip Address (Fixed to “101”) 
R/W: READ/WRITE (Fixed to “0”: READ Only) 
D9-D0: SAR ADC Data 
Figure 97. Serial Control I/F Timing (10bit SAR ADC Data)