SCI/LIN Control Registers
1669
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
Serial Communication Interface (SCI)/ Local Interconnect Network (LIN)
Module
29.7.2 SCI Global Control Register 1 (SCIGCR1)
The SCIGCR1 register defines the frame format, protocol, and communication mode used by the SCI.
and
illustrate this register.
Figure 29-29. SCI Global Control Register 1 (SCIGCR1) (offset = 04h)
31
26
25
24
Reserved
TXENA
RXENA
R-0
R/W-0
R/W-0
23
18
17
16
Reserved
CONT
LOOP BACK
R-0
R/W-0
R/W-0
15
14
13
12
11
10
9
8
Reserved
STOP EXT
FRAME
HGEN CTRL
CTYPE
MBUF MODE
ADAPT
SLEEP
R-0
R/WL-0
R/WL-0
R/WL-0
R/W-0
R/WL-0
R/W-0
7
6
5
4
3
2
1
0
SWnRST
LIN MODE
CLOCK
STOP
PARITY
PARITY ENA
TIMING MODE
COMM MODE
R/W-0
R/W-0
R/W-0
R/WC-0
R/WC-0
R/W-0
R/WC-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; WL = Write in LIN mode only; WC = Write in SCI-compatible mode only; -
n
= value after reset
Table 29-12. SCI Global Control Register 1 (SCIGCR1) Field Descriptions
Bit
Field
Value
Description
31-26
Reserved
0
Reads return 0. Writes have no effect.
25
TXENA
Transmit enable. This bit is effective in LIN and SCI modes. Data is transferred from SCITD, or
the TDy (with y=0, 1,...7) buffers in LIN mode to the SCITXSHF shift out register only when the
TXENA bit is set.
0
Transfers from SCITD or TDy to SCITXSHF are disabled.
1
Transfers from SCITD or TDy to SCITXSHF are enabled.
Note: Data written to SCITD or the transmit multi-buffer before TXENA is set is not
transmitted. If TXENA is cleared while transmission is ongoing, the data previously
written to SCITD is sent (including the checksum byte in LIN mode).
24
RXENA
Receive enable. This bit is effective in LIN and SCI modes. RXENA allows or prevents the
transfer of data from SCIRXSHF to SCIRD or the receive multi-buffers.
0
The receiver will not transfer data from the shift buffer to the receive buffer or multi-buffers.
1
The receiver will transfer data from the shift buffer to the receive buffer or multi-buffers.
Note: Clearing RXENA stops received characters from being transferred into the receive
buffer or multi-buffers, prevents the RX status flags from being updated by receive data,
and inhibits both receive and error interrupts. However, the shift register continues to
assemble data regardless of the state of RXENA.
Note: If RXENA is cleared before a frame is completely received, the data from the frame
is not transferred into the receive buffer.
Note: If RXENA is set before a frame is completely received, the data from the frame is
transferred into the receive buffer. If RXENA is set while SCIRXSHF is in the process of
assembling a frame, the status flags are not guaranteed to be accurate for that frame. To
ensure that the status flags correctly reflect what was detected on the bus during a
particular frame, RXENA should be set before the detection of that frame.
23-18
Reserved
0
Reads return 0. Writes have no effect.
17
CONT
Continue on suspend. This bit is effective in LIN and SCI modes. This bit has an effect only
when a program is being debugged with an emulator, and it determines how the SCI/LIN
operates when the program is suspended. The SCI/LIN counters are affected by this bit: when
the bit is set the counters are not stopped, when the bit is cleared the counters are stopped
during debug mode.
0
When debug mode is entered, the SCI/LIN state machine is frozen. Transmissions and LIN
counters are halted and resume when debug mode is exited.
1
When debug mode is entered, the SCI/LIN continues to operate until the current transmit and
receive functions are complete.