Datasheet RN41, RN41N (Microchip) - 8

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RN41/RN41N 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 RN41/RN41N module, including radio PCB footprint for the RN41 and RN41N, respectively. interference, factory reset, solder reflow profile, con- When laying out the carrier board for the RN41 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 RN41/RN41N contains a weak internal pull-up to mounting details for the RN41 and RN41N, respec- VCC, and the reset polarity is active low. The module’s tively. For optimal radio performance, the RN41 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 RN41 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: RN41 RECOMMENDED
such as the MCP809 or MCP102/121.
PCB FOOTPRINT 2.2 Factory Reset Using GPIO4
7RS9LHZ It is recommended to connect the GPIO4 pin to a PP switch, jumper, or resistor so it can be accessed. This PP 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 Host PCB to the factory defaults, GPIO4 should be high on Ground Plane Edge power-up and then toggle between low and high twice with a 1 second wait between the low-high transitions. PP
2.3 Connection Status
GPIO5 is available to drive an LED, and it blinks at var- ious speeds to indicate status, see Table 2-1. GPIO2 is an output that directly reflects the connection state as shown in Table 2-2. Shield Pads X4
TABLE 2-1: GPIO5 STATUS
0.8 mm x 1.3 mm Do not locate vias
GPIO5 Status Description
or signal traces under Shield Pads Toggle at 1 Hz The module is discoverable and waiting for a connection. Toggle at 10 Hz The module is in command mode. 'LPHQVLRQVDUHLQPLOOLPHWHUV High The module is connected to another device over Bluetooth.
TABLE 2-2: GPIO2 STATUS GPIO5 Status Description
High The module is connected to another device over Bluetooth. Low The module is not connected over Bluetooth. DS50002280A-page 8  2014 Microchip Technology Inc. Document Outline 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 (RN41N) TABLE 2-3: Tested External Antenna Types 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: RN41 European Compliance Testing TABLE 3-2: RN41N European Compliance Testing 3.4 Australia 3.5 New Zealand 4.0 Ordering Information TABLE 4-1: Ordering Information Class 1 Bluetooth® Module with EDR Support Worldwide Sales and Service