User's Manual

Table Of Contents
UART S3C2450X RISC MICROPROCESSOR
15-20
3.8 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
UMSTAT0 Bit Description Initial State
Delta CTS [4] Indicate that the nCTS input to the S3C2450 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