Samsung S3C2416 User Manual page 325

S3C2416X RISC MICROPROCESSOR
2.1.4 Non Auto-Flow Control (Controlling nRTS and nCTS by Software)
If users want to connect a UART to a Modem, disable auto flow control bit in UMCONn register and control the
signal of nRTS by software.
Example:
Rx Operation with FIFO
1. Select receive mode (Interrupt or DMA mode).
2. Check the value of Rx FIFO count in UFSTATn register. If the value is less than 32, users have to set the
value of UMCONn[0] to '1' (activating nRTS), and if it is equal or larger than 32 users have to set the
value to '0' (inactivating nRTS).
3. Repeat the Step 2.
Tx Operation with FIFO
1. Select transmit mode (Interrupt or DMA mode).
2. Check the value of UMSTATn[0]. If the value is '1' (activating nCTS), users write the data to Tx FIFO
register.
3. Repeat the Step 2.
2.1.5 RS-232C Interface
If the user wants to connect the UART to modem interface (instead of null modem), nRTS, nCTS, nDSR, nDTR,
DCD and nRI signals are needed. In this case, the users can control these signals with general I/O ports by
software because the AFC does not support the RS-232C interface.
UART
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