RN42N-I/RM Roving Networks, RN42N-I/RM Datasheet - Page 8

• Manufacturer Part Number: RN42N-I/RM
• Description: Bluetooth / 802.15.1 Modules Class2 Bluetooth Mod v2.0+EDR w/o Antenna
• Manufacturer: Roving Networks

Specifications of RN42N-I/RM

• Product Category: Bluetooth / 802.15.1 Modules
• Rohs: yes
• Frequency Band: 2.4 GHz
• Data Rate: 1200 bps to 921 Kbps
• Operating Supply Voltage: 3.3 V
• Output Power: 2 dBm
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Modulation Technique: FHSS, GFSK

In this mode, the Bluetooth stack is no longer on-board the module. It is offloaded to the interfacing host processor. The
Bluetooth module is used as a radio, performing the lower level MAC functionalities, while the application stack runs on the
host processor.
Using the module in HCI mode allows designers to implement profiles that are not natively supported on the Bluetooth
module.
Roving Networks offers HCI mode in two hardware interfaces:
HCI over UART
In this mode, the hardware interface between the host processor and the Bluetooth module is the UART. You must
interface the flow control signals between the host processor and the Bluetooth module for the HCI interface to work.
Failure to do so can cause the host processor and the Bluetooth module to become out of sync and break the Bluetooth
link.
HCI over USB
In this mode, the hardware interface between the host processor and the Bluetooth module is the USB. In this
architecture, the Bluetooth module is the USB slave and the host processor is the USB host.
Using the USB interface offers the advantage of a faster data link between the Bluetooth module and the host processor.
With this architecture, it is possible to achieve Bluetooth’s theoretical maximum throughput of 3 Mpbs.
Low Power
To achieve low-power operation, hold the module’s RESET pin low. With RESET = 0 VDC, the module consumes 35 uA of
power. If RESET is left floating or high, the module consumes 3 mA in sleep mode. To obtain the lowest power, the RN-42
should be passive (in slave mode and not trying to make connections).
Using the SPI Bus to Upgrade the Flash Memory
While not required, this bus is very useful for configuring the Bluetooth modules’ advanced parameters. The bus is
required when upgrading the module’s firmware. The typical application schematic shown in Figure 4 shows a 6-pin
header that can be implemented to gain access to this bus. A minimum-mode version might simply use the SPI signals (4
pins) and obtain ground and VCC from elsewhere in the design.
Minimizing Radio Interference
When laying out the carrier board for the RN-42 module, the areas under the antenna and shielding connections should
not have surface traces, ground planes, or exposed vias (see Figure 5). For optimal radio performance, the RN-42
module’s antenna end should protrude at least 5 mm beyond any metal enclosure.
www.rovingnetworks.com
NOTE: HCI mode requires a separate firmware build that must be loaded into the module’s flash at the factory. Is not
•
•
HCI over UART
HCI over USB
upgradeable in the field.
Version 2.31r 10/15/2012
RN -42 -DS
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