RN4870 click
RN4870 click

Description of product

RN4870 click carries the RN4870 Bluetooth® 4.2 low energy module from Microchip. The click is designed to run on a 3.3V power supply. It uses ASCII Command Interface over UART for communication with target microcontroller, with additional functionality provided by the following pins on the mikroBUS™ line: PWM, INT, RST, CS.

RN4870 module features

RN4870 module features

The RN4080 module from Microchip provides a complete solution to implement Bluetooth 4.2 Low Energy connectivity.

All products in the RN series can be dynamically configured by the host microcontroller with a few simple ASCII commands.

The RN4870 supports both peripheral and central Generic Access Profile (GAP) roles, actively scanning for other connectable devices instead of waiting for incoming connection requests. The peripherals are usually small, low power devices like sensors and monitors, that broadcast information to the central device. The central device can communicate with multiple peripherals.

It also supports Remote Command mode which allows a remote device to access Command mode remotely via Bluetooth link. 

The module contains an integral ceramic chip antenna.


ApplicationsHealth/Medical Devices, Sports Activity/Fitness Meters, Beacon Applications, Internet of Things (IoT) Sensor Tag, Remote Control, Wearable Smart Devices and Accessories, Smart Energy/Smart Home, Industrial Control
MCURN4870 BLE 4.2 low energy module
Key FeaturesASCII Command Interface API over UART, ISM Band 2.402 to 2.480 GHz Operation, Secure AES128 Encryption
Input Voltage3.3V
Click board sizeM (42.9 x 25.4 mm)

Pinout diagram

This table shows how the pinout on RN4870 click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

NotesPinMikrobus logo.png                  Pin                  Notes
Module ResetRST2RSTINT15UART_CTS       UART Clear To Send    
UART Ready To Send    UART_RTS   3CSTX14UART_TXDUART Data output
Power supply+3.3V73.3V5V10NC

Additional pins

Name   I/O   Description
RX_IIUART RX Indication pin
RSSII/OIndicate the quality of the link based on the RSSI level.
PAIRIUse this pin to force the module to enter Standby mode.
LINKIUse this pin to force the module to drop the current BLE link with a peer device.

Buttons and LEDs

Designator     NameType    Description
LD1PWRLEDPower indicator LED
LD2   ON/OFF      LEDProvides indication whether the module is in ON/OFF mode   

Maximum ratings

Supply Voltage1.93.6V
Frequency Band2.4022.480GHz    
Operating Temperature Range       -20°C   +70°C   


Code examples for RN4870 click, written for MikroElektronika hardware and compilers are available on Libstock.

Code snippet

The following code snippet shows send function for RN4xxx clicks. If the message type is correct, it will estabilish connection with the device specified by the address in the parameter and then send the properly formated data.

01 #define BTCMD( TXT ) UART2_Write_Text( TXT )
02 void RN4xxx_send(char *pAddr, T_RN4xxx_message msgData )
03 {
04    static char msgTxt [255];
06    if (msgData.msgType ==  'Q')
07    {
08        /*Connects to a device with specified adress*/
09        BTCMD("C,1,");
10        BTCMD (pAddr);
11        BTCMD("r");
12        Delay_ms(3000);
13        /*Secures the connection, entering data stream mode*/
14        BTCMD("Br");
15        Delay_ms(3000);
16    }
17    /*Sentence construction */
18    msgTxt[0] = '#';
19    msgTxt[1] = msgData.msgType;
20    msgTxt[2] = ',';
21    msgTxt[3] = msgData.dataType/0x100;
22    msgTxt[4] = msgData.dataType%0x100;
23    msgTxt[5] = ',';
24    msgTxt[6] = msgData.id;
25    msgTxt[7] = ',';
26    msgTxt[8] = '';
27    strcat (msgTxt, msgData.payload);
28    strcat (msgTxt, "*rn");
30    BTCMD ( msgTxt );
32    if (msgData.msgType ==  'Q')
33    {
34        Delay_ms(3000);
35        /*Enters CMD mode*/
36         BTCMD("$");
37        Delay_ms(100);
38        BTCMD("$$$");
39        Delay_ms(1000);
40        /*Kills connection*/
41        BTCMD("K,1r");
42        Delay_ms(500);
43    }
44 }