AK8999A Datasheet, PDF (30/68 Pages) Asahi Kasei Microsystems – Pressure Sensor Control IC

CONFIDENTIAL
[AK8999A/AW/AD]
1.3) OSC Adjustment (completed when shipped in package form)
The intermittent operation control clock is adjusted to 1000kHz.
Oscillation frequency can be adjusted without monitoring frequency directly.
The high level for the fixed period (2.0msec ± 1%) is inputted from the CSCLK pin after the writing of an
adjustment mode register (C address: 00h, data: AM[3:0] = 3h). The internal clock pulses are counted in
the integrated counter circuit, and the count value is stored in the control register (C address: 01h, data:
CT[7:0]). The adjustment data (address: 10h, data: EFR[3:0]) for oscillation frequency is calculated from
the stored count value. The adjustment can be done within 1000kHz ± 5% accuracy by writing the
adjustment data in EEPROM. Since the error of High period turns into an adjustment error of frequency,
please set period as 2.0ms ± 1%.
Twr_REG Tcont=2.0ms±1%
1
4
9
16
1
CSCLK
Pulse Count.
VOUT
Analog
Output
I2
The explanation of oscillation frequency adjustment data (address: 10h, data: EFR[3:0]) is as
follows.
The count value stored in the control register (C address: 01h, data: CT[7:0]) is read for the ratio
check. A ratio will be 0% (ideal value), when the High level period of CSCLK pin is 2 msec and
the frequency of the internal oscillator is 1000kHz. The ratio varies from 0% by the error of High
level period and the frequency variation of the internal oscillator. And the High time which can
be set up becomes a range from which a ratio will be -99% to 154%. Be aware that the error is
easily affected when the ratio is small. The counter value shown as FF hex means overflow,
please measure again by changing High level period.
Please set the adjustment data of oscillation frequency as the sum of the ratio of CT [7:0] data and
the ratio of EFR [3:0] data is close to 0%.
Address : 01 hex D[7:0]= CT[7:0]
CT[7:0]
Count value
Dec Hex
Bin
0 00 00000000
(time)
0
1 01 00000001
1
：：
：
：
98 62 01100010
98
99 63 01100011
99
100 64 01100100
100
101 65 01100101
101
102 66 01100110
102
：：
：
：
254 FE 11111110
254
255 FF 11111111
-
Ratio
(%)
0
-99
：
-2
-1
0
1
2
：
154
-
Description
Default
Ideal value
Counter error
MS1600-E-00
- 30 -
2014/05