Writing data into the dual-port | Cypress Semiconductor
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Writing data into the dual-port
- After the data is clocked into the sync DPRAM, on which clock is the data actually written to the memory?
- How long does it take for data written into the dual-port to be accessible?
The data is written into memory on the same cycle as the write operation. A write operation consists of applying both the valid data and address before the rising edge of the clock. Generally, there is parameter in synchronous dual-ports called tCWDD (write port clock HIGH to read data delay). This parameter describes how early after a word is written, it can be read. For example, if one port writes a word into the dual-port at time t=x, then the other port can try to read that memory location instantly. There is only a slightly longer delay to when the data at that memory location is driven onto the data lines. This delay, tCWDD, is true for cases when the second port tries to access the new word within tCCS of the writing port.