S3C84E5/C84E9/P84E9

UART

 

 

UART MODE 0 FUNCTION DESCRIPTION

In mode 0, UART is input and output through the RxD (P1.4) pin and TxD (P1.5) pin outputs the shift clock. Data is transmitted or received in 8-bit units only. The LSB of the 8-bit value is transmitted (or received) first.

Mode 0 Transmit Procedure

1.Select mode 0 by setting UARTCON.6 and .7 to "00B".

2.Write transmission data to the shift register UDATA (F5H) to start the transmission operation.

Mode 0 Receive Procedure

1.Select mode 0 by setting UATCON.6 and .7 to "00B".

2.Clear the receive interrupt pending bit (UARTPND.1) by writing a "0" to UARTPND.1.

3.Set the UART receive enable bit (UARTCON.4) to "1".

4.The shift clock will now be output to the TxD (P1.5) pin and will read the data at the RxD (P1.4) pin. A UART receive interrupt (vector E4H) occurs when UARTCON.1 is set to "1".

Write to Shift Register (UDATA)

Shift

RxD (Data Out)

D0

D1

D2

D3

D4

D5

D6

D7

TxD (Shift Clock)

 

 

 

 

 

 

 

 

TIP

Write to UARTPND (Clear RIP and set RE)

RIP

RE

Shift

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RxD (Data In)

 

 

 

 

D0

 

 

 

 

D1

 

 

 

 

D2

 

 

 

 

D3

 

 

 

 

D4

 

 

 

 

D5

 

 

 

 

D6

 

 

 

 

D7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TxD (Shift Clock)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Transmit

Receive

1

2

3

4

5

6

7

8

Figure 13-6. Timing Diagram for UART Mode 0 Operation

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Samsung S3C84E5 user manual Uart Mode 0 Function Description, Mode 0 Transmit Procedure, Mode 0 Receive Procedure, 13-9