WT21_13 datasheet(21/57 Pages) ETC2

21 / 57 page

Bluegiga Technologies Oy

Page 21 of 56

UART configuration parameters, such as baud rate and packet format, are set using WT21

firmware.

Note:

An accelerated serial port adapter is required to communicate with the UART at maximum baud rate

using a standard PC.

Table 10: Possible UART Settings

Note:

Baud rate is the measure of symbol rate i.e. , the number of distinct symbol changes (signaling events)

made to transmission medium per second in a digitally modulated signal.

The UART interface is capable of resetting WT21 on reception of a break signal. A break is

identified by a continuous logic low (0V) on the UART_RX terminal, as shown in Figure 9. If

tBRKis longer than the value, defined by the PSKEY_HOSTIO_UART_RESET_TIMEOUT, (0x1a4),

a reset occurs. This feature allows a host to initialise the system to a known state. Also, WT21

can emit a break character that may be used to wake the host. By default this feature is

disabled and it is recommended to enable it by setting PSKEY_HOSTIO_UART_RESET_TIMEOUT.

Figure 8: Break Signal

Table 11 shows a list of commonly used baud rates and their associated values for the

PSKEY_UART_BAUDRATE (0x1be). There is no requirement to use these standard values. Any

baud rate within the supported range can be set in the PS Key according to the formula in

Equation XXX.

Equation 1: Baud Rate

WT21 Datasheet(PDF) 21 Page - List of Unclassifed Manufacturers