ak4516a AKM Semiconductor, Inc., ak4516a Datasheet - Page 17

• Manufacturer Part Number: ak4516a
• Description: 3v 16bit Adc&dac With Built-in Pga
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
2. Semi-auto Mode
The semi-auto mode is the mode that uses the AK4516A auto limitter function, and the recovery operation is
processed by uP or DSP etc.
During the semi-auto mode, writing to the following registers from uP is inhibited.
M0026-E-00
LRGA, LTM1-0, ZELM, LMTH1-0, LMAT2-0
10
1
2
3
4
5
6
7
8
9
Setting up the registers for the semi-auto mode operation.
(LTM1-0, ZELM, LMTH1-0, LMAT2-0, IPGL, IPGR, LRGA="1", GSEL)
WR(LMTE="1", RCVE="0"): After the registers concerned in the auto limitter operation is set up and
As the input signal of ADC exceeds LMTH, the auto limitter operation starts.
WR(IPGA="31H"):As the auto limitter is in operation, writing by uP is ignored.
After the zero crossing operation of both Lch and Rch is completed, the next operation starts.
RD(LCDET&IPGA):Confirm to complete auto limitter operation and reads the IPGA present value.
WR(IPGA="2FH"):Update IPGA value.
WR(LMTE="0")
In Figure 7 , since "0" is written to LMTE during ATT operation, the operation changes to manual mode
after completing ATT operation. After confirming LCDET="1", it is possible to change the each register
set-up. If LMTE is set "0" during the auto limitter operation or the update of the IPGA value by uP ,
LCDET becomes "1" after the max "1" ATT/GAIN operation is completed by internal state.
In this case, the input signal of ADC exceeds LMTH, the auto limitter does not operate because of
LMTE="0".
Figure 7 . Control example of semi-auto mode operation(LMAT = 1 step, ZENM=ZELM="1")
confirming the zero crossing flags(ZFIPL,ZFIPR)="1", LMTE is set "1".
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[AK4516A]
1998/08