SPRUJ79 November 2024 F29H850TU , F29H859TU-Q1
To reduce CPU load when receiving or transmitting data in interrupt mode or RTDMA mode, the SCI/LIN module has eight separate receive and transmit buffers. Multibuffered mode is enabled by setting the MBUF MODE bit.
The multibuffer 3-bit counter counts the data bytes transferred from the SCIRXSHF register to the RDy receive buffers and TDy transmit buffers register to SCITXSHF register. The 3-bit compare register contains the number of data bytes expected to be received or transmitted. the LENGTH value in SCIFORMAT register indicates the expected length and is used to load the 3-bit compare register.
A receive interrupt (RX interrupt; see the SCIINTVECT0 and SCIINTVECT1 registers), and a receive ready RXRDY flag set in SCIFLR register, as well as a RTDMA request (RXDMA) can occur after receiving a response if there are no response receive errors for the frame (such as, there is, frame error, and overrun error).
A transmit interrupt (TX interrupt), and a transmit ready flag (TXRDY flag in SCIFLR register), and a RTDMA request (TXDMA) can occur after transmitting a response.
Figure 1-1 and Figure 40-9 show the receive and transmit multibuffer functional block diagram, respectively.
Figure 40-8 Receive Buffers
Figure 40-9 Transmit Buffers