NEC Network Controller uPD98502 - Manual (Page 423)

CHAPTER 8 UART
Preliminary User’s Manual S15543EJ1V0UM 423
8.3.12 UARTMSR (UART Modem Status Register)
This register reports the current state of and changes in various control signals.
Bits Field R/W Default Description
31:8 Reserved R/W 0 Hardwired to 0.
7 DCD R/W 0 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.
6 RI R/W 0 Ring Indicator.
1 = not valid.
0 = always reads 0.
This bit has no associated external signal.
5 DSR R/W 0 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.
4 CTS R/W 0 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.
3 DDCD R/W 0 Delta Data Carrier Detect.
1 = URDCD_B state changed since this register was last read.
0 = no such change.
2 TERI R/W 0 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.
1 DDSR R/W 0 Delta Data Set Ready.
1 = URDSR_B input signal changed since this register was last read.
0 = no such change.
0 DCTS R/W 0 Delta Clear To Send.
1 = URCTS_B state changed since this register was last read.
0 = no such change.
8.3.13 UARTSCR (UART Scratch Register)
This register contains a UART reset bit plus 8 bits of space for any software use.
Bits Field R/W Default Description
31:8 Reserved R/W 0 Hardwired to 0.
7:0 USCR R/W - UART Scratch Register.
Available to software for any purpose.