Samsung S3C2416 User Manual page 334

UART
UCONn
Transmit Mode
(note 3)
Receive Mode
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. 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.
Recommended steps are follows.
- Disable Receive Mode
- Set GPIO as UART mode.
- RX FIFO reset.
- Interrupt unmask(enable) if needed
- Enable Receive Mode(Set Receive Mode to Interrupt/DMA request or polling mode)
5. In the middle of operation, changing source clock selection or speed of source clock is prohibited. These must be done
after finishing transmission/receiving
6. Mask bit of INTMSK(Interrupt Mask Register ) should be 0 (unmask) before enabling Transmit mode as Interrupt request
mode.
14-14
Bit
[3:2] Determine which function is currently able to write Tx data to the
UART transmit buffer register.
00 = Disable
01 = Interrupt request
10 = DMA request( request signal 0)
11 = DMA request( request signal 1)
[1:0] Determine which function is currently able to read data from
UART receive buffer register.
00 = Disable
(note 4)
01 = Interrupt request or polling mode
10 = DMA request( request signal 0)
11 = DMA request( request signal 1)
Description
or polling mode
(note 6)
S3C2416X RISC MICROPROCESSOR
Initial State
00
00