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Philips Semiconductors
Preliminary User Manual
LPC2119/2129/2292/2294
ARM-based Microcontroller
UART1 Modem Status Register (U1MSR - 0x0xE0010018)
The U1MSR is a read-only register that provides status information on the modem input signals. U1MSR3:0 is cleared on U1MSR
read. Note that modem signals have no direct affect on UART1 operation, they facilitate software implementation of modem
signal operations.
Table 99: UART1 Modem Status Register Bit Descriptions (U1MSR - 0x0xE0010018)
U1MSR
Function
Description
Reset
Value
0
Delta CTS
0: No change detected on modem input, CTS.
1: State change detected on modem input, CTS.
Set upon state change of input CTS. Cleared on an U1MSR read.
0
1
Delta DSR
0: No change detected on modem input, DSR.
1: State change detected on modem input, DSR.
Set upon state change of input DSR. Cleared on an U1MSR read.
0
2
Trailing Edge RI
0: No change detected on modem input, RI.
1: Low-to-high transition detected on RI.
Set upon low to high transition of input RI. Cleared on an U1MSR read.
0
3
Delta DCD
0: No change detected on modem input, DCD.
1: State change detected on modem input, DCD.
Set upon state change of input DCD. Cleared on an U1MSR read.
0
4
CTS
Clear To Send State. Complement of input signal CTS. This bit is connected to
U1MCR[1] in modem loopback mode.
0
5
DSR
Data Set Ready State. Complement of input signal DSR. This bit is connected to
U1MCR[0] in modem loopback mode.
0
6
RI
Ring Indicator State. Complement of input RI. This bit is connected to U1MCR[2] in
modem loopback mode.
0
7
DCD
Data Carrier Detect State. Complement of input DCD. This bit is connected to
U1MCR[3] in modem loopback mode.
0