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Is CDC asynchronous?
Understanding Asynchronous Oracle CDC (Change Data Capture) As the name suggests, this is an asynchronous process and does not cause any performance hit.
How do you create asynchronous FIFO?
An asynchronous FIFO refers to a FIFO design where data values are written to a FIFO buffer from one clock domain and the data values are read from the same FIFO buffer from another clock domain, where the two clock domains are asynchronous to each other.
Does Oracle have CDC?
Oracle CDC (Change Data Capture) is the technology that efficiently identifies and captures data that has been added to, updated, or deleted from Oracle tables, and makes the change data available for use by destination applications.
What is GREY FIFO?
You use gray code counters in asynchronous FIFO design where the write pointer is in a different clock domain than the read pointer, AND, when the pointers are multi-bit. This is to correctly detect full and empty conditions.
Do you need full and empty conditions in asynchronous FIFO?
However, with the clock crossing we need to ensure that FIFO full and empty conditions are taking into account the clock crossing cycles. In other words, pessimistic full and empty conditions need to be added. Here’s an example to 8-deep FIFO with Write in aclk domain and read in bclk domain:
How to cross clock domains with an asynchronous FIFO?
In the case of the asynchronous FIFO, this is also done specifically using a clock associated with the write channel, i_wclk. I’ve also used AW to reflect the address width of this memory. I’ll probably still refer to this as N throughout in this text.
Why do we need a synchronizer in FIFO?
The synchronizer ensures that read and write pointers calculations are consistent and data in FIFO is not accidentally overwritten or read twice. However, with the clock crossing we need to ensure that FIFO full and empty conditions are taking into account the clock crossing cycles.
What happens if I try to write into FIFO?
If appropriate precautions are not taken then we could end up in a scenario where write into FIFO has not yet finished and we are attempting to Read it or Vice-versa. This scenario often causes data loss and Metastability issues. In order to avoid such scenarios, the reading and writing is done via a synchronizer.