Specifications

6. SERIAL INTERFACES

6.1 UART Interface

WT32 Universal Asynchronous Receiver Transmitter (UART) interface provides a simple

mechanism for communicating with other serial devices using the RS232 standard. The

UART interface of WT32 uses voltage levels from 0 to VDD_IO and thus an external

transceiver IC is required to meet the voltage level specifications of RS232.

Figure 7: WT32 UART interface

Four signals are used to implement the UART function, as shown in Figure 7. When WT32

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. DTR, DSR

and DCD signals can be implemented by using PIO terminals of WT32. All UART

connections are implemented by using CMOS technology and have signaling levels of 0V

and VDD_IO.

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.

Parameter

Possible values

1200 baud (≤2%Error)

Minimum

9600 baud (≤1%Error)

Baud rate

Maximum 3.0Mbaud (≤1%Error)

Flow control

RTS/CTS, none

Parity

None, Odd, Even

Number of stop bits

1 or 2

Bits per channel

Table 10: Possible UART settings

UART_TX

UART_RX

UART_RTS

UART_CTS

WT32