Uart Modem Control Register - Samsung S3C2416 User Manual

UART

3.4 UART MODEM CONTROL REGISTER

There are three UART MODEM control registers including UMCON0 and UMCON1 in the UART block.
Register
UMCON0 0x5000000C
UMCON1 0x5000400C
UMCON2 0x5000800C
UMCONn
RTS trigger
Level
Auto Flow
Control (AFC)
Reserved
Request to Send
NOTES:
1. UART 3 does not support AFC function, because the S3C2416 has no nRTS3 and nCTS3.
2. If AFC bit is enabled and Time-out bit is disabled, RTS trigger level must be lager than Rx FIFO trigger level.
3. Example ) RX interrupt mode, RTS trigger level b101(24byte), RX FIFO trigger level b10(16byte).
This example shows RX FIFO always contains equal or less than 24 bytes.
(have space equal or larger than 40bytes.)
FIFO FIFO Spare
contains
40 byte
24 byte
41 byte
23 byte
...
47 byte
17 byte
48 byte
16 byte
49 byte
15 byte
14-16
Address R/W
R/W UART channel 0 Modem control register
R/W UART channel 1 Modem control register
R/W UART channel 2 Modem control register
Bit
[7:5] When AFC bit is enabled, these bits determine when to inactivate
(High) nRTS signal.
000 = When RX FIFO contains 63 bytes.
001 = When RX FIFO contains 56 bytes.
010 = When RX FIFO contains 48 bytes.
011 = When RX FIFO contains 40 bytes.
100 = When RX FIFO contains 32 bytes.
101 = When RX FIFO contains 24 bytes.
110 = When RX FIFO contains 16 bytes.
111 = When RX FIFO contains 8 bytes.
[4] 0 = Disable
1 = Enable
[3:1] These bits must be 0's
[0] If AFC bit is enabled, this value will be ignored. In this case the
S3C2416 will control nRTS automatically.
If AFC bit is disabled, nRTS must be controlled by software.
0 = 'H' level (Inactivate nRTS)
1 = 'L' level (Activate nRTS)
nRTS
space
signal
High
Low
... Low
Low
Low
Low
Description
Description
Interrupt Note
-
RTS trigger Level
-
-
-
Occur RX FIFO trigger Level
-
S3C2416X RISC MICROPROCESSOR
Reset Value
Initial State
0x0
0x0
0x0
000
0
00
0