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PmodBT2™ Reference Manual
Revised August 17, 2011
This manual applies to the PmodBT2 rev. A
DOC#: 502-214
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 1 of 3
The PmodBT2.
Bluetooth 2.1/2.0/1.2/1.1 compatible
Simple UART Interface
A wide range of modes including: Slave Mode, Master
Mode, Trigger Master Mode, Auto-connect Master Mode,
Auto-connect DTR Mode, and Auto-connect ANY Mode.
Small form factor: 1.5" x 0.8"
Features include:
Overview
The PmodBT2 is a powerful peripheral module employing the Roving Networks® RN-42 to create a fully integrated
Bluetooth interface.
1 Functional Description
The PmodBT2 uses a standard 12-pin connection and communicates via UART. There is a secondary SPI header on
the board for updating the RN-42 firmware if needed.
1.1 Jumper Settings
The PmodBT2 has several modes available to the user via jumper settings. JP1 through JP4 provide various modes
of operation as indicated in Table 1 below. Each jumper is active when shorted. JP1 restores the device to factor
default settings after three transitions of the jumper setting (short-to-open or open-to-short). After the third
transition, the device returns to factor default except for the Bluetooth name. The other three jumpers, JP2-JP4,
only sample in the first 500 ms of operation to allow the pins that they tie to on the RN-42 module to serve a
separate purpose later in the modules operation. JP2 enables pairing with a special device class defined by the
user in software. This may be used so that the PmodBT2 operates as a substitute for an RS232 cable. JP3 enables
auto connect to a stored address defined by the user. Finally, JP4 chooses whether to operate at the stored baud
rate (115.2kbps default) or a baud rate of 9600 regardless of the software selected rate when shorted. For more
detailed information on jumper settings and functionality, refer to the RN-42 user manual.
PmodBT2™ Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 2 of 3
Jumper
Description
JP1 (PIO4)
Factory Default
JP2 (PIO3)
Auto Discovery/Pairing
JP3 (PIO6)
Auto Connect
JP4 (PIO7)
Baud Rate Setting (9600)
Roving
Network
RN-42
RTS
RXD
TXD
CTS
GND
VCC
1
2
3
4
5
6
7
8
9
10
11
12
STATUS
VCC
RST
NC
NC
GND
J1
1 2
VCC
JP1
JP2
JP3
3
4
6
5
8
7
JP4
4
5
6
1
2
3
MISO
VCC
MOSI
SCK
CS
GND
J2
Table 1. Set jumper description.
Figure 1. PmodBT2 block diagram.
1.2 UART Interface
By default, the UART interface uses a baud rate of 115.2 kbps, 8 data bits, no parity, and a single stop bit. The
startup baud rate may be customized to predefined rates or set to a specific user customized baud rate.
Predefined baud rates range from 1200 to 921k.
The reset pin (RST) on J1 is active low. If the RST pin is toggled, the device will undergo a hard reset. This hard reset
performs similarly to a power cycling of the device. The second interface besides the standard UART signals is the
STATUS pin also on J1The STATUS pin directly reflects the connection status of the device. STATUS is driven high by
the device when connected and is driven low otherwise.
For more information on the devices UART interface and RST and STATUS pins refer to the RN-42 user manual on
the Roving Networks website.
1.3 Command Mode
In order to enter the command mode, the PmodBT2 must receive "$$$" to which it will respond "CMD". When in
command mode, the module will respond to a large number of commands allowing the user to customizing the
PmodBT2™ Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 3 of 3
Connector J1 – UART Communications
Pin
Signal
Description
1
RTS
Ready to Send
2
RX
Receive
3
TX
Transmit
4
CTS
Clear to Send
5
GND
Power Supply
Ground
6
VCC
Power Supply
(3.3V)
7
STATUS
Connection Status
8
~RST
Reset
9
NC
Not Connected
10
NC
Not Connected
11
GND
Power Supply
Ground
12
VCC
Power Supply
(3.3V)
Connector J2 – SPI Connector (Firmware Update Only)
1
MISO
Master in/ Slave
out
2
MOSI
Master out/ Slave
in
3
SCK
Serial Clock
4
~CS
Chip Select
5
VCC
Power Supply
(3.3V)
6
GND
Power Supply
Ground
module for specific applications. In order to exit command mode, send "---<cr>" (three minus signs in a row and
where <cr> stands for the carriage return character) to which the device will respond "END". Remote
configuration, or configuration over a Bluetooth connection, is possible through the command mode but has
several restrictions. The configure time, which defaults to 60 sec, defines the time window in which the PmodBT2
may be configured remotely. Outside of this time, the PmodBT2 will not respond to any remote commands. It is
important to note that any of the "set" commands available for the PmodBT2 must be followed by a power cycle
to take effect in any design.
Table 2. Connector descriptions.
The various modes of operation are accessed by using the "SM,<5,4,3,2,1,0>" command while in command mode.
The PmodBT2 can be put into one of six available modes of operation. The modes in order, 0 to 5, are: slave,
master, trigger master, auto-connect, auto-connect DTR, and auto-connect ANY. For more detailed information on
the different modes of operation, refer to the RN-42 user manual. For the full list of device commands, how to use
remote configuration, and more detailed information on the different modes of operation, see the RN-42 data.
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