RD0
RD1
RD2
RD3
RD4
RD5
RD6
RD7
0
7
0
7
0
7
0
7
0
7
0
7
0
7
0
7
3-bit
Counter
CE Flag
3-bit
Compare
=
RX DMA Request
CHECKSUM
CALCULATOR
MBUF MODE
RX Ready Flag
Not
MBUF MODE
No
Receive
Errors
SCIRXSHF
0
7
RX
SCI
1633
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
Serial Communication Interface (SCI)/ Local Interconnect Network (LIN)
Module
29.2.1.5 SCI Multi Buffered Mode
To reduce CPU load when Receiving or Transmitting data in interrupt mode or DMA mode, the SCI/LIN
module has eight separate Receive and transmit buffers. Multi buffered mode is enabled by setting the
MBUF MODE bit.
The multi-buffer 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 SCIINTVECT1registers), and a receive ready
RXRDY flag set in SCIFLR register, as well as a DMA request (RXDMA) could 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 DMA
request (TXDMA) could occur after transmitting a response.
and
shows the receive and transmit multi-buffer functional block diagram.
Figure 29-8. Receive Buffers