Samsung S3C2451X User Manual page 359

S3C2451 RISC MICROPROCESSOR
UART CONTROL REGISTER (Continued)
UCONn
3)
Transmit Mode [3:2]
Receive Mode [1:0]
NOTES:
1) When you want to change EXTUARTCLK to PCLK for UART baudrate, clock selection field must be set to 2'b10.
2) When the UART does not reach the FIFO trigger level and does not receive data during 3 words time in Interrupt receive
mode with FIFO, the Rx interrupt will be generated (receive time out), and the users should check the FIFO status
and read out the rest.
3) If Tx DMA request signal were 0, Rx DMA request signal should be 1. They can't share request signal 0 or 1 in common.
(UCONn[3:2], UCONn[1:0]) = ("10b", "11b") or ("11b", "10b")
4) Before enable Receive mode, Please finish setting of GPIO. When Receive mode is enabled, changing of GPIO status
affect to RXD line(example : GPIO RXD ->GPIO input -> GPIO RXD), dummy data can be read at RX fifo. (depends on
the duration of GPIO is set as input at a certain baudrate setting)
Recommended steps are follows.
- Disable Receive Mode
- read Current GPIO setting, save to variable.
- change setting GPIO to variable.
- Save variable to GPIO register.
- Set Uart Registers
- RX fifo reset.
- then ready to receive data
Bit
Determine which function is currently able to write Tx data to the
UART transmit buffer register.
00 = Disable
01 = Interrupt request or polling mode
10 = DMA request( request signal 0)
11 = DMA request( request signal 1)
Determine which function is currently able to read data from
UART receive buffer register.
4)
00 = Disable
01 = Interrupt request or polling mode
10 = DMA request( request signal 0)
11 = DMA request( request signal 1)
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
UART
Initial State
00
00
15-11