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CHAPTER 7 UART
454
Preliminary User’s Manual S14767EJ1V0UM00
7.3.10 UART Modem Status Register (UARTMSR) (98H, R/W)
This register reports the current state of and changes in various control signals.
Bits
Field
Description
0
DCTS
Delta Clear To Send.
1 = URCTS_B state changed since this register was last read.
0 = no such change.
1
DDSR
Delta Data Set Ready.
1 = URDSR_B input signal changed since this register was last read.
0 = no such change.
2
TERI
Trailing Edge Ring Indicator.
1 = RI_B state changed since this register last read.
0 = no such change.
RI_B is not implemented as an external signal, so this bit is never set by the controller.
3
DDCD
Delta Data Carrier Detect.
1 = URDCD_B state changed since this register was last read.
0 = no such change.
4
CTS
Clear To Send.
1 =URCTS_B state active.
0 = URCTS_B state inactive.
This bit is the complement of the URCTS_B input signal. If the LOOP bit in the UART Modem
Control Register (UARTMCR), is set to 1, the CTS bit is equivalent to the RTS bit in the UARTMCR.
5
DSR
Data Set Ready.
1 = URDSR_B state active.
0 = URDSR_B state inactive.
This bit is the complement of the URDSR_B input signal. If the LOOP bit in the UART Modem
Control Register (UARTMCR), is set to 1, the DSR bit is equivalent to the DTR bit in the
UARTMCR.
6
RI
Ring Indicator.
1 = not valid.
0 = always reads 0.
This bit has no associated external signal.
7
DCD
Data Carrier Detect.
1 =URDCD_B state active.
0 = URDCD_B state inactive.
This bit is the complement of the URDCD_B input signal. If the LOOP bit in the UART Modem
Control Register (UARTMCR), is set to 1, the DCD bit is equivalent to the OUT2 bit in the
UARTMCR.
31:8
Reserved
Hardwired to 0.