Samsung S3C2451X User Manual page 361

S3C2451 RISC MICROPROCESSOR
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
Reserved 0x5000C00C
UMCONn
RTS trigger [7:5]
Level
Auto Flow
Control (AFC)
Reserved [3:1]
Request to Send
NOTES:
1. UART 3 does not support AFC function, because the S3C2451X 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 have space equal or larger then 40bytes.
Fifo contains
24 byte
23 byte
...
17 byte
16 byte
15 byte
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
– Reserved
Bit
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
These bits must be 0's
[0] If AFC bit is enabled, this value will be ignored. In this case the
S3C2451X will control nRTS automatically.
If AFC bit is disabled, nRTS must be controlled by software.
0 = 'H' level (Inactivate nRTS)
Fifo Space nRTS
40 byte High
41 byte Low
... Low
47 byte Low
48 byte Low
49 byte Low
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.
Description
Description
1 = Enable
1 = 'L' level (Activate nRTS)
Interrupt
-
-
-
-
Occur
-
UART
Reset Value
0x0
0x0
0x0
Undef
Initial State
000
0
00
0
15-13