RN-42-DS Datasheet, PDF (7/12 Pages) List of Unclassifed Manufacturers – RN-42/RN-42-N Class 2 Bluetooth Module

RN-42-DS
 
DESIGN CONCERNS  
The following sections provide information on designing with the RN-42 module, including radio interference, factory reset,
solder reflow profile, connection status, etc.
Reset Circuit
The RN-42 contains a 1k pullup to VCC, and the reset polarity is active low. The module’s reset pin has an optional power-
on-reset circuit with a delay, which should only be required if the input power supply has a very slow ramp or tends to
bounce or have instability on power up. Often a microcontroller or embedded CPU I/O is available to generate the reset
once power is stable. If not, designers can use one of the many low-cost power supervisor chips currently available, such
as the MCP809, MCP102/121, and Torex XC61F.
Factory Reset Using GPIO4
Roving Networks recommends that designers connect the GPIO4 pin to a switch, jumper, or resistor so it can be accessed.
This pin can be used to reset the module to its factory default settings, which is critical in situations where the module has
been misconfigured. To reset the module to the factory defaults, GPIO4 should be high on power-up and then toggle low,
high, low, high with a 1 second wait between the transitions.
Connection Status
GPIO5 is available to drive an LED, and it blinks at various speeds to indicate status (see Table 7). GPIO2 is an output that
directly reflects the connection state as shown in Table 8.
Table 8. GPIO5 Status
GPIO5 Status
Toggle at 1 Hz
Toggle at 10 Hz
Low
Description
The module is discoverable and waiting for a connection.
The module is in command mode.
The module is connected to another device over Bluetooth.
Table 9. GPIO2 Status
GPIO2 Status
High
Low
Description
The module is connected to another device over Bluetooth.
The module is not connected over Bluetooth.
HCI Mode
Roving Networks offers the Host Controller Interface (HCI) mode in addition to the standard operational mode of its
Bluetooth modules (standard mode refers to the on-board stack running on the module).
In HCI mode, the on-board stack is bypassed and the module is put in a state that runs the Bluetooth baseband. The HCI
provides a command reference interface to the baseband controller and the link manager, and provides access to the
hardware status and control registers. This interface provides a uniform method for accessing the Bluetooth baseband
capabilities.
www.rovingnetworks.com
Version 2.31r 10/15/2012
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