3.5.3 RN4870 BLE Module

The RN4870 is a Bluetooth® Low Energy (BLE) module that integrates a Bluetooth® 5.0 baseband controller, on-board Bluetooth stack, digital and analog I/O, and RF power amplifier into one solution.

Additional Features:
  • Range up to 50m
  • Operating voltage range: 1.9V to 3.6V
  • TX / RX mode peak current: 10 mA (typical)
  • Low-Power mode current: 60 μA (typical)
  • Shutdown current: 2.9 μA (max.)
The RN4870 BLE module is connected to the PIC16LF18456 through UART as well as three GPIOs for the control and configuration of the module. The RST signals reset the module, while the RX_IND signal is used to wake the module from Low-Power mode. The MODE signal, available from the PIC16LF18456, the debugger as well as by a physical switch, allows the module to be put in a “Test Mode” where the RN4870 firmware can be updated.

The module has two of its GPIO pins connected to LEDs. By default, the BLE LED will indicate connection status, while ERR LED must be controlled by the user. Both LEDs can be configured for several other functions. Many of the other RN4870 GPIO pins are available as pads around the label on the backside of the PIC-BLE board, as can be seen in Figure 1-2.

Info: Some RN4870 settings have been changed during the manufacturing of PIC-BLE. Using the S- command, the device name has been changed to “PIC-BLE”. Also, the communication settings have been configured for PIC16LF18456 EUSART settings of 9600,8,N,1.
Table 3-4. RN4870 Connections
RN4870 PinPIC16LF18456 PinFunctionShared Functionality
RXRC4EUSART TX—
TXRC5EUSART RX—
RSTRA0GPIO—
P2_0 / MODERA7GPIOMechanical Switch and On-board debugger
P3_3 / RX_INDRC6GPIO—
P1_1 / STATUS1—Connection LED (BLE)BLE LED
P2_2—Custom configurable LED (ERR)ERR LED
Info: The RST and MODE signals are pulled up by external resistors.