SLVSHF3 October 2024 LP5899-Q1
PRODUCTION DATA
The TXFIFO level (TXFFLVL) controls the start of the transmission of the CCSI controller for SPI forward commands that are independent of the SPI CRC. With correct setting of the FIFO level, FIFO overflow and underflow can be prevented. The setting is dependent on the difference between the SPI clock frequency and CCSI clock frequency, the accuracy of the clock provided to the SPI peripheral, accuracy of the clock of the CCSI controller, and the maximum length of data that is being forwarded.
The RXFIFO level (RXFFLVL) controls the Data Ready (DRDY) interrupt. When the number of data words on the RXFIFO exceed the RXFFLVL, the DRDY pin becomes logic LOW. This DRDY pin remains logic LOW until there are no more words on the RXFIFO. The RXFFLVL setting has the same dependencies as the TXFFLVL except the maximum length of data that is being forwarded is replaced by the maximum number of data words that is received by the CCSI peripheral. An example of the DRDY pin's behavior is depicted in Figure 7-7.
The DRDY pin also becomes logic LOW when an END byte is detected and the number of words on the RXFIFO has not reached the RXFFLVL yet.