How can I put the module into a test mode for FCC or another type of certification?

The easiest way to get the module to do the specified data pattern is to use a module with HCI firmware. It is available on microchipDIRECT, the part number is RN42HCI-I/RM.

You need to have a UART COM port from a PC. The UART signal level has to be 3.3 VDC, otherwise, the Bluetooth module will be damaged.

The definition of a PC UART COM port is:

  1. It is a 3.3VDC UART interface.
  2. It is accessible from a PC with a terminal program like HyperTerm or TeraTerm.
  3. It could be native from a PC RS232 with an RS232 to 3.3 V UART-like driver.
  4. It could also be in the form of a FTDI or Prolific USB to UART adapter.

To ensure the correct connection, try to connect to the RN42HCI-I/RM module from the PC UART COM port only before putting the module on to your system board.

To use the module for a certification test:


Connect a UART COM port from a PC to the module. You need to connect TX, RX, CTS, and RTS to the module if possible. If the UART COM port does not come with CTS/RTS, you need to short CTS/RTS on the module side.


Install CSR BlueSuite 2.3 for XP or 2.5 for Windows® 7 or 8. (BlueSuite™ is available directly from CSR.)


Open BlueTest3 from CSR BlueSuite program group.

A window will pop up.


Select H4 as transport.


Select the PC COM that is connected to the module as Serial Port. The PC COM port number may need to be under COM 10.


Select 115200 as baud rate.


You can start the test with BlueTest3.

After you verify that you can use PC UART COM port to work with CSR BlueTest, you can solder the module on to your system board. You will need to ensure that the MCU connecting to the module with certification firmware (HCI module) is disconnected. That is because the MCU could interfere with CSR BlueTest3 operation. You may need to cut a few traces to do it. If you can still control the module from CSR BlueTest3 now, you are done. Your lab can use it to do certification testing.

Note: The standard RN42-I/RM module will not work with BlueSuite. The HCI module is necessary.

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