User's Manual

20
7. PHYSICAL INTERFACES
7.1 UART Interface
WT11 Universal Asynchronous Receiver Transmitter (UART) interface provides a simple
mechanism for communicating with other serial devices using the RS232 standard
1
.
UART_TX
UART_RX
UART_RTS
UART_CTS
WT12
Figure 6: WT11 UART interface
Four signals are used to implement the UART function, as shown in Figure 11.12. When
WT11 is connected to another digital device, UART_RX and UART_TX transfer data
between the two devices. The remaining two signals, UART_CTS and UART_RTS, can be
used to implement RS232 hardware flow control where both are active low indicators. All
UART connections are implemented using CMOS technology and have signaling levels of
0V and VDD_PADS.
Notes:
In order to communicate with the UART at its maximum data rate using a standard PC, an
accelerated serial port adapter card is required for the PC.
1. Uses RS232 protocol but voltage levels are 0V to VDD_USB, (requires external
RS232 transceiver chip)
Parameter Possible values
1200 baud (d2%Error)
Minimum
9600 baud (d1%Error)
Baud rate
Maximum 3.0Mbaud (d1%Error)
Flow control RTS/CTS, none
Parity None, Odd, Even