W90221X Winbond Electronics Corp America, W90221X Datasheet - Page 167

• Manufacturer Part Number: W90221X
• Description: Pa-risc Embedded Controller
• Manufacturer: Winbond Electronics Corp America

Modem Status Register (MSR)
Port address : 0xf00003fe (COM0)
Default : ---
Bits 0 Complement version of Data Carrier Detect (DCD#) input
Bits 1 Complement version of Ring Indicator (RI#) input
Bits 2 Complement version of Data Set Ready (DSR#) input
Bits 3 Complement version of Clear to Send (CTS#) input
Bits 4 DCD# state change
Bits 5 Tailing edge of RI
Bits 6 DSR# state change
Bits 7 CTS# state change
Whenever either of MSR[4:7] is set to logic 1, a Modem Status Interrupt is
generated if IER[4]=1.
Writing LSR is a null operation (not suggested).
W90221X version 0.6
DCD#
0
This bit is set whenever DCD# input has changed state, and it will be
reset if the CPU reads
the MSR.
This bit is set whenever TI# input has changed from high to low, and
it will be reset if the
CPU reads the MSR.
This bit is set whenever DSR# input has changed state, and it will be
reset if the CPU reads
the MSR.
This bit is set whenever CTS# input has changed state, and it will be
reset if the CPU reads
the MSR.
RI#
0xf00002fe (COM1)
1
DSR#
2
CTS#
3
DDCD
4
TERI
Read only
5
DDSR
6
Power-on
DCTS
7
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