ak4516a AKM Semiconductor, Inc., ak4516a Datasheet - Page 19

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

ASAHI KASEI
3. Full-auto Mode
The full-auto mode is done automatically by the auto limitter and the auto recovery function of the AK4516A.
However, writing to the register is needed to enable these functions.
During the full-auto mode, writing to the following registers from uP is inhibited.
M0026-E-00
LRGA, LTM1-0, ZELM, LMTH1-0, LMAT2-0, WTM1-0, NRTM1-0, RATT1-0, ZENM, REF6-0, IPGL, IPGR
1
2
3
4
5
6
7
8
9
Set-up the registers of full-auto mode
(LTM1-0, ZELM, LMTH1-0, LMAT2-0, WTM1-0, RATT1-0, NRTM1-0, ZENM, REF6-0, GSEL, IPGL,
IPGR, LRGA="1")
WR(LMTE=RCVE="1"): After the registers concerned in the auto limitter operation is set up and
confirming the zero crossing flags(ZFIPL, ZFIPR)="1", LMTH and RCVE are set "1".
WR(IPGA="31H"):As the operation is full-auto mode, writing by uP is ignored.
The ready of recovery starts.
As the input signal of ADC exceeds LMTH, the recovery operation (in the figure, recovery ready) is
discontinued and the limitter operation starts.
WR(LMTE=RCVE="0"):The full-auto mode operation is completed.
In Figure 9 , since "0" is written to LMTE& RCVE during the ATT operation, the operation changes to the
manual mode after completing ATT operation. After confirming LCDET="1", it is possible to change the
each register set-up. If LMTE&RCVE are set "0" during the full-auto mode operation, 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=RCVE="0".
After the limitter operation is completed, the AK4516A waits for the time set by WTM1-0. If the input
signal does not exceed (LMTH - 2dB), the recovery operation is executed. After the waiting time finishes
the next waiting time starts immediately. In recovery ready, the waiting timer is reset under the condition
of (LMTH - 2dB) Input Signal<LMTH. And the timer starts under the condition of (LMTH - 2dB)>Input
Signal.
Figure 9 . Control example of full-auto mode operation (LMAT=RATT: 1 step, ZENM=ZELM="1")
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[AK4516A]
1998/08