Sony CXD5602 User Manual page 275

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Valid data amount can be readout separately
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Watermark Level (Almost Full) can be set separately
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Interrupts/DMA transfer requests such as the following can be generated separately
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When the valid data amount becomes equal to or higher than the Watermark, an interrupt is asserted,
and when it falls below the Watermark, an interrupt is negated.
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When the valid data amount becomes equal to or higher than the Watermark, DMA_BREQ is
asserted, and when 1 or larger, DMA_SREQ is asserted.
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When the DMA_CLR from the DMAC becomes "1", the DMA_BREQ and DMA_SREQ are once
negated, and the DMA_BREQ and DMA_SREQ are asserted again in accordance with the valid
data amount.
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FIFO Clear (setting is enforced as valid data amount = 0) can be performed separately
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Equips a separate time stamp readout register
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From the time stamp readout register, the value that corresponds to the below readable data can be obtained.
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The time stamp value is calculated from the following formula:
"the time stamp that corresponds to the latest value - (valid data amount -1) x data capture interval"
3.9.8.8 Time Stamp
Each partition excluding the Random Access partition has time stamp information.
Time stamps are count values of 47 bits that are incremented at 32.768 kHz intervals. The upper 32 bits indicate
"integer part of second" while the lower 15 bits are values of "second after the decimal point".
3.9.8.8.1 Time Stamp Value Handling at the Writing Side
The partition to which data is written from the SCU (internal sequencer) is directly connected to the time stamp
information supplied from the other block, and the writing side time stamp information is updated according to the
data writing timing.
The partition to which data is written from the CPU has the following registers which can be set from the CPU.
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Reference time stamp value
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Writing time interval value
The CPU first writes the reference time stamp value and writing time interval value. Then, each time the CPU
writes data to the FIFO, the writing time interval value is cumulatively added to the reference time stamp value.
The cumulatively added time stamp value can be read out as the register value by the CPU.
Time stamp generation logic when reading out
Within the FIFO, the time stamp values of each datum are not stored together in the FIFO, instead, the writing
side (latest) time stamp values and the writing time interval values are stored.
The readout side time stamps are values calculated during readout by the following equation.
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CXD5602 User Manual