AK09912 Datasheet, PDF (23/42 Pages) HuaXinAn Electronics CO.,LTD – 3-axis Electronic Compass

[AK09912]
7.1.2. Reading Data
Input the R/W control bit (R/W=“1”) and 7-bit register address on SI pin in synchronous with the first 8 bits of the 16 bits of
a serial clock input on SK pin. Then AK09912 outputs the data held in the specified register with MSB first from SO pin.
When clocks are input continuously after one byte of data is read, the address is incremented and data in the next address is
output. Accordingly, after the falling edge of the 15th clock and CSB pin is “L”, the data in the next address is output on SO
pin. When CSB pin is driven “L” to “H”, SO pin is placed in the high-impedance state.
AK09912 has two incrimination lines; 00H to 18H and 30H to 32H. For example, data is read as follows: 00H  01H 
02H  03H  10H  11H ...  18H  00H  01H ..., 30H  31H  32H  30H …,or 60H  61H  62H  60H
…
33H to 35H and 37H are reserved addresses. Do not access to those addresses.
When specified address is other than 00H to 18H, 30H to 37H and 60H to 62H, AK09912 recognizes that it is not selected
and keeps SO pin in high-impedance state. Therefore, user can use other addresses for other devices.
CSB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
SK
SI
(INPUT)
SO
(OUTPUT)
RW A6 A5 A4 A3 A2 A1 A0
6
Hi-Z
D7 D6 D5 D4 D3 D2 D1 D0
Hi-Z
Figure 7.2 4-wire SPI Reading Data
MS1547-E-02
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2014/7