Datasheet RN42, RN42N (Microchip) - 7

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RN42/RN42N 2.0 APPLICATION INFORMATION 2.4 Module Mounting Details
The following sections provide information on design- Figure 2-1 and Figure 2-2 show the recommended ing with the RN42/RN42N module, including radio PCB footprint for the RN42 and RN42N, respectively. interference, factory reset, solder reflow profile, con- When laying out the carrier board for the RN42 module, nection status, and so on. the areas under the antenna and shielding connections should not have surface traces, ground planes, or
2.1 Reset Circuit
exposed vias. Figure 2-3 and Figure 2-4 show the recommended The RN42/RN42N contains a weak internal pull-up to mounting details for the RN42 and RN42N, respec- VCC, and the reset polarity is active low. The module’s tively. For optimal radio performance, the RN42 mod- reset pin has an optional Power-on Reset circuit with a ule’s antenna end should protrude at least 31 mm delay, which should only be required if the input power beyond any metal enclosure. supply has a very slow ramp or tends to bounce or have instability on power-up. Often a microcontroller or Figure 2-5 shows examples of good, bad, and accept- embedded CPU I/O is available to generate the reset able positioning of the RN42/RN42N on the host PCB. once power is stable. If not, designers can use one of the many low-cost power supervisor chips available,
FIGURE 2-1: RN42 RECOMMENDED
such as the MCP809 or MCP102/121.
PCB FOOTPRINT 2.2 Factory Reset Using GPIO4
It is recommended to connect the GPIO4 pin to a Top View switch, jumper, or resistor so it can be accessed. This pin can be used to reset the module to its factory 25.8 default settings, which is critical in situations where the module has been misconfigure d. To reset the module 20.5 to the factory defaults, GPIO4 should be high on 19.7 power-up and then toggle between low and high twice 0.70mm 2.00mm with a 1 second wait between the low-high transitions. 16.0 14.8 0.80mm 13.6
2.3 Connection Status
12.4 11.2 GPIO5 is available to drive an LED, and it blinks at var- 10.0 8.8 ious speeds to indicate status, see Table 2-1. GPIO2 is 7.6 an output that directly reflects the connection state as 6.4 5.2 shown in Table 2-2. 4.0
TABLE 2-1: GPIO5 STATUS
2.8 Shield Pads 0.7 4 Corners 1.0 x 1.8mm
GPIO5 Status Description
0.0 Do not locate Toggle at 1 Hz The module is discoverable and vias or surface waiting for a connection. traces under 0.0 1.1 2.6 3.6 4.9 6.1 7.3 8.5 9.8 10.8 12.3 13.4 Shield Pads Toggle at 10 Hz The module is in command mode. High The module is connected to Dimensions are in millimeters another device over Bluetooth.
TABLE 2-2: GPIO2 STATUS GPIO2 Status Description
High The module is connected to another device over Bluetooth. Low The module is not connected over Bluetooth.  2015 Microchip Technology Inc. DS50002328A-page 7 Document Outline Class 2 Bluetooth® Module with EDR Support Table of Contents 1.0 Device Overview 1.1 MCU Interface 1.2 ASCII Command and Data Interface TABLE 1-1: Environmental Conditions TABLE 1-2: Electrical Characteristics TABLE 1-3: Module Dimensions TABLE 1-4: Radio Characteristics TABLE 1-5: Digital I/O Characteristics TABLE 1-6: Pin Description 2.0 Application Information 2.1 Reset Circuit 2.2 Factory Reset Using GPIO4 2.3 Connection Status TABLE 2-1: GPIO5 Status TABLE 2-2: GPIO2 Status 2.4 Module Mounting Details 2.5 External Antenna Types (RN42N) 2.6 HCI Mode 2.7 Soldering Recommendations 2.8 SPI Interface 2.9 Bluetooth SIG QDID 2.10 Application Schematic 3.0 Regulatory Approval 3.1 United States 3.2 Canada 3.3 Europe TABLE 3-1: RN42 European Compliance Testing 3.4 Australia 3.5 New Zealand 3.6 Japan 3.7 Korea 3.8 Taiwan 4.0 Ordering Information TABLE 4-1: Ordering Information(1) Worldwide Sales and Service