AK8998 Datasheet, PDF (37/59 Pages) Asahi Kasei Microsystems – Preliminary

[AK8998/W/D]
Serial Interface Description
The data of EEPROM and control register (volatile memory) in the AK8999 can be written and read
through a two-wire serial interface, consisting of CSCLK pin and VOUT pin. When CSCLK=High is
maintained beyond a definite period of time (1.0 msec), VOUT output will change from the Analog output
to SDI/O (Serial data I/O).
And data is captured from VOUT synchronously with the rising edge of CSCLK after SDI/O shift. Input data
contains three instruction bits (I2 - I0), five address bits (A4 - A0) and eight data bits (D7 - D0). Provide the
data in the order of I2 → I0 → A4 → A0 → D7 → D0. And when CSCLK=Low is maintained beyond a
definite period of time (0.5 msec), VOUT output will return from SDI/O to the Analog output.
On the WRITE instruction, allow 5msec or more write time for EEPROM and 10µsec or more write time for
the control register (see Twr in 6) Digital AC Characteristics in the Electrical Characteristics section). For
the READ instruction, data is written up to 8CLK for CSCLK and the data output starting at the rising edge
of 9CLK is read out.
1) Data Configuration
Configuration of data written to or read out through the serial interface is shown below. There are 16
specific bits of data in total comprised of three instruction bits, five address bits and eight data bits.
Instruction
Address
Data
I2 I1 I0 A4 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0
Data input direction
2) Description of Instructions
Instruction codes are summarized below.
Code ^{Note 1)}
I2
I1
I0
Instruction
Description
1
1
0 EEPROM read Reads out the data written in the EEPROM
(Read Mode)
1
0
1 EEPROM write Writes data to the EEPROM. Write time (from 16^th
(Write Mode) CSCLK rising edge to CSCLK falling edge) requires
5msec or more.
EEPROM
batch write
If the 1Fh address is written, input data is written to all
addresses except for 1Eh. Write time (from 16^th CSCLK
(Write Mode) rising edge to CSCLK falling edge) requires 10msec or
more.
0
1
0 Control reg. read Reads out the data written in the control register.
(Read Mode)
0
0
1 Control reg. write Writes the data to the control register. Write time (from
(Write Mode) 16^th CSCLK rising edge to CSCLK falling edge) requires
10µsec or more.
Note) Instructions other than this are prohibited.
MSxxxxx-E-00
- 36 -
2012/11