
[AK4673] 
MS0670-E-00 
2007/09 
- 72 - 
■
 Digital I/F 
The AK4673 operates with uP via I
2
C bus and supports the standard-mode (100 KHz) and the fast-mode (400KHz). 
Please note that the AK4673 operates in those two modes and does not support a High speed mode I
2
C-bus system 
(3.4MHz). The AK4673 can operate as a slave device on the I
2
C bus network. 
TSVDD 
AK4673
Micro- 
Processor 
I
2
C bus 
controller 
SCL 
SDA 
TSVDD=2.6V – 3.6V 
CADT
PENIRQN 
Rp 
Rp 
“L” or “H” 
Figure 65 Digital I/F 
■
 Serial Control Interface 
The AK4673 supports the fast-mode I
2
C-bus (max: 400 kHz). Pull-up resistors at the SDA and the SCL pins should be 
connected to (TVDD1/ TSVDD +0.3) V or less voltage. The TVDD1 pin and the TSVDD pin should be connected 
together on  the same I2C bus.  
[Start condition and Stop condition] 
A HIGH to LOW transition on the SDA line while SCL is HIGH indicates a START condition. All sequences start by the 
START condition or Repeated Start Condition. Repeated Start condition is the same signal tradition as Start condition. 
A LOW to HIGH transition on the SDA line while SCL is HIGH defines a STOP condition. All sequences are terminated 
by the STOP or Repeated Start condition. Repeated Start is also the Start condition of next transfer so that I
2
C bus cannot 
be idle. 
SCL 
SDA 
P : stop condition 
S : Start condition 
S/Sr 
 Sr : Repeated start condition
Figure 66 START and STOP Conditions 
[Data transfer] 
All commands are preceded by a START condition. After the START condition, a slave address is sent. After the 
AK4673 recognizes the START condition, the device interfaced to the bus waits for the slave address to be transmitted 
over the SDA line. If the transmitted slave address matches an address for one of the devices, the designated slave device 
pulls the SDA line to LOW (ACKNOWLEDGE). The data transfer is always terminated by a STOP condition generated 
by the master device. 
[Data validity] 
The data on the SDA line must be stable during the HIGH period of the clock. The HIGH or LOW state of the data line 
can only change when the clock signal on the SCL line is LOW except for the START and the STOP condition.