Samsung S3C2440A User Manual
Page 323
S3C2440A RISC MICROPROCESSOR
UART
11-19
UART MODEM STATUS REGISTER
There are two UART modem status registers including UMSTAT0, UMSTAT1 in the UART block.
Register Address R/W
Description
Reset
Value
UMSTAT0
0x5000001C
R
UART channel 0 Modem status register
0x0
UMSTAT1
0x5000401C
R
UART channel 1 Modem status register
0x0
Reserved 0x5000801C - Reserved
Undef
UMSTAT0 Bit
Description
Initial
State
Delta CTS
[4]
Indicate that the nCTS input to the S3C2440A has changed
state since the last time it was read by CPU.
(Refer to Figure 11-8.)
0 = Has not changed
1 = Has changed
0
Reserved [3:1]
0
Clear to Send
[0]
0 = CTS signal is not activated (nCTS pin is high)
1 = CTS signal is activated (nCTS pin is low)
0
nCTS
Delta CTS
Read_UMSTAT
Figure 11-7. nCTS and Delta CTS Timing Diagram