AK8999A Datasheet, PDF (43/68 Pages) Asahi Kasei Microsystems – Pressure Sensor Control IC

CONFIDENTIAL
[AK8999A/AW/AD]
16. Serial Interface Description
The data of EEPROM and control register (volatile memory) in the AK8999A can be written and read through a
2-wire serial interface on CSCLK pin and VOUT pin. When CSCLK = High is maintained beyond a definite
period of time (1.0msec), 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 (0.5msec), 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 7) Digital AC Characteristics in the Electrical Characteristics). 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)
I2
I1
I0
Instruction
Description
1
1
0
EEPROM read Read out the data written in the EEPROM
(Read Mode)
1
0
1
EEPROM write Write data to the EEPROM. Write time (from 16^th CSCLK
(Write Mode) 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 rising
(Write Mode) edge to CSCLK falling edge) requires 10msec or more.
0
1
0 Control reg. read Read out the data written in the control register.
(Read Mode)
0
0
1 Control reg. write Write the data to the control register. Write time (from 16^th
(Write Mode) CSCLK rising edge to CSCLK falling edge) requires 10μsec
or more.
Note) Instructions other than this are prohibited.
MS1600-E-00
- 43 -
2014/05