Sony CXD5602 User Manual page 868


The maximum value of cnt_out is 32767(2^15-1).

Since the SAMP_RATIO is directly connected from the register to the comparator for comparing the counter
value, when the software is changed, it is immediately reflected.

Counter reset is common to all four channels (reset cannot be done on a counter basis).
Dynamic update of the SAMP_RATIO is not considered (the specification is such that parameters are updated
when the internal counter is reset).
0
cnt_out
LPADC_DATAEN
SAMP_RATIO
LPADC_DATAEN_SMP
When a reset of the internal counter is not performed, and the sampling frequency is changed from low to high, a
large delay may occur.
The delay until the first datum can be extracted is as follows:

When the first time each channel of LPADC is started up
1/RPOST (RPOST = RPRE) [seconds]
E.g.: When 256 Hz, approximately 3.9 ms

After the LPADC stops, startup with sampling frequency changed, not resetting the LPADC

In the case of sampling frequency change (High => Low) (SAMP_RATIO Low => High)
Maximum
1/RPOST
Minimum
1/RPOST – 1/RPRE + 1/RADC

In the case of sampling frequency change (Low => High) (SAMP_RATIO High => Low)
Minimum
1/RADC
Maximum
32768/RADC
E.g.: when 256 Hz, 128s
Here,
RADC: Sampling rate of LPADC (Hz)
RPRE: Sampling rate after decimation before change (Hz)
RPOST: Sampling rate after decimation after change (Hz)
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Figure SCU (Sensor Control Unit)-93 Counter Basic Operation
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2
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CXD5602 User Manual
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