Gu, John A. (US SSA) wrote:
The ADC will do nothing until a trigger command written into its
register. It then makes a sampling, and within a usec it puts the
digital data in another latched register mapped into IO address for the
program to read. This is called the single operation, in other words, no
trigger no sampling. Though it is capable to have a maximum sample rate
of 10K per second, but it all depends on how fast and accurate the
program can do.
[snip]
Ok, this is fine. But how many samples/sec do you actually *need*?
If all you need is 100 samples/sec then there is no point in doing
anything special. All you need to do is run a task each 10ms and
trigger the chip, then hang and wait in the device driver for 100us.
No big deal. (Unless that blows other time constraints.)
If the chip has a ready/busy line, then that can probably be
connected back to the sample command line to cause continuous
operation.
Do you really, really, really need 10K samples/sec? If so,
then probably a little external hardware with a FIFO chip
connected should be put between the A/D and the CPU. Then
an ordinary task can come along and read out the FIFO on
some periodic basis.
Mike
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