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ISD91200 Series Technical Reference Manual
Release Date: Sep 16, 2019
- 378 -
Revision 2.4
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Setup FIFO data width SDADC_CTL.FIFOBITS
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Setup down ampling rate, set SDADC_CTL.RATESEL=0 then set SDADC_CTL.DSRATE &
BIQ_CTL.SDADCWNSR for expected DSR & sampling rate(refer to Table 7-1)
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Setup PDMA channel to receive data from SDADC.
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Enable PDMA request.
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Enable SDADC conversion(SDADC_EN.SDADCEN).
To operate the SDADC
the entire analog path from analog input to SDADC needs to be configured
for correct operation with BIQ and SDADC Volume control:
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Selecting and powering up VMID reference: power on VMID generator, power on both low and
high value resistor.
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Wait 7 RC time, then turn off lower value resistor, and then wait 1or 2 RC time.
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Enable SDADC clock source (CLK_APBCLK0.SDADCCKEN, CLKSEL1.SDADCSEL).
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Reset SDADC block. (SYS_IPRST1.EADCRST).
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Enable SDADC power (SDCHOP.SDADC_PD = 0)
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Power up FEPGA and MICBIAS.
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Setup sample rate based on current MCLK frequency and Set SDADC_CLKDIV
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Setup FIFO data width SDADC_CTL.FIFOBITS
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Setup down ampling rate, set SDADC_CTL.RATESEL=0 then set SDADC_CTL.DSRATE &
BIQ_CTL.SDADCWNSR for expected DSR & sampling rate(refer to Table 7-1).
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Enable BIQ clock source (CLK_APBCLK0.BIQALCKEN).
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Enable BIQ on SDADC path (BIQ_CTL.DLCOEFF, BIQ_CTRL.BIQEN,
BIQ_CTL.PATHSEL=0, BIQ_CTRL.STAGE, BIQ_CTRL.HPFON).
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Set BIQ coefficient(BIQ_COEFF)
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Setup SDADC volume control (VOLCTRL_EN.SDADCVOLEN,VOLCTRL_ADCVAL).
(note: setup BIQ_CTL.DLCOEFF =1 and BIQ enable BIQ_CTL.BIQEN =1 for BIQ operation).
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Setup PDMA channel to receive data from SDADC.
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Enable PDMA request.
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Enable SDADC conversion(SDADC_EN.SDADCEN).
7.1.4.4
Interrupt Sources
The SDADC can be configured to generate an interrupt when the data level in the FIFO exceeds a
defined threshold. The interrupt condition is only cleared by disabling the interrupt or reading values
from the FIFO. In addition two comparators can monitor the SDADC FIFO output to generate interrupts
when set levels are exceeded.
FIFOIELEV
INT.IE
SDADC_CMPR1.CMPF
SDADC_CMPR1.CMPIE
ADC_IRQ
SDADC_CMPR0.CMPF
SDADC_CMPR0.CMPIE
Figure 7-2 SDADC Controller Interrupt