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Manual Documentation Number: ZPXXx-XXXXx-XR-0812
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104 –
www.bb-elec.com
B&B Electronics – Westlink Commercial Park – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445 –
www.bb-europe.com
<Serial Interfacing> BD
Command allows the user to
adjust the UART interface data
rate and thus modify the rate at
which serial data is sent to the RF
module. The new baud rate does
not take effect until the CN
command is issued. The RF data
rate is unaffected by the BD
parameter.
Most applications will require one
of the seven standard baud rates;
however, non-standard baud
rates are also supported.
Note: If the interface data rate is
set to exceed the fixed RF data
rate of the module, flow control
may need to be implemented as
described in the Pin, Flow Control
and CS (DO2 Configuration)
sections.
Non-standard Interface Data Rates:
When parameter values outside the range of
standard interface data rates are sent, the closest rate represented by the number is
stored in the BD register. For example, a rate of 19200 bps can be set by sending the
following command line "ATBD4B00". When the BD command is sent with a non-
standard interface data rate, the UART will adjust to accommodate the requested
interface rate. In most cases, the clock resolution will cause the stored BD parameter
to vary from the parameter that was sent (refer to the table below). Reading the BD
command (send "ATBD" command without an associated parameter value) will return
the value that was actually stored in the BD register.
Parameter Sent vs. Parameter Stored BD Parameter Sent (HEX) Interface Data
Rate (bps)
BD Parameter
Sent (HEX)
Interface Data Rate (bps)
BD Parameter
Stored (HEX)
0
1200
0
4
19,200
4
7
115,200
7
12C
300
12B
1C200
115,200
1B207
AT Command: ATBD
Binary Command: 0x15 (21 decimal)
Parameter Range (Standard baud rates): 0
– 6
(Non-standard baud rates): 0x7D
– 0xFFFF
Parameter
Configuration (bps)
0
1200
1
2400
2
4800
3
9600
4
19200
5
38400
6
57600
Number of bytes returned: 2
Default Parameter Value: Set to equal module‟s
factory-set RF data rate.
Related Commands: CN (Exit Command Mode)
Minimum firmware version required: 4.2B
(Custom baud rates not previously supported.)
