Preliminary
S3C2451 RISC MICROPROCESSOR
UART
15-17
Preliminary product information describe products that are in development,
for which full characterization data and associated errata are not yet available.
Specifications and information herein are subject to change without notice.
UART MODEM STATUS REGISTER
There are three 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
UMSTAT2
0x5000801C
R
UART channel 2 modem status register
0x0
Reserved 0x5000C01C
–
Reserved
Undef
UMSTAT0 Bit
Description
Initial
State
Delta CTS
[4]
Indicate that the nCTS input to the S3C2451X has changed state
since the last time it was read by CPU.
(Refer to Figure 15-8.)
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 15-8. nCTS and Delta CTS Timing Diagram