 2015 Microchip Technology Inc.

DS50002279B-page 7

RN4020

3.0

MICROCONTROLLER TO

RN4020 INTERFACE

Figure 3-1 illustrates the interface between PIC

microcontroller and the RN4020 module.

The minimum interface consists of UART and

WAKE_HW lines. This enables the microcontroller to

communicate with the RN4020 module using ASCII

command API. The command API is described in

Section 6.0 “ASCII Command API”.

3.1

CTS/RTS Hardware Flow Control

For customer applications using the Microchip Low-

energy Data Profile, Pin 8 (CMD/MLDP) is required.

CTS/RTS hardware control is also required for this

service to avoid buffer overruns.

3.2

Microchip Low-energy Data Profile

(MLDP)

The Microchip Low-energy Data Profile is a private

BTLE service that provides a 50 kbps serial data trans-

port over Bluetooth Low Energy on the RN4020. Pin 8

(CMD/MLDP) is required. CTS/RTS hardware control

is also highly recommended for this service to avoid

data loss.

For more information on how to use the MLDP data ser-

vice, refer to RN4020 Bluetooth Low Energy

Module User’s Guide (DS70005191).

FIGURE 3-1:

INTERFACE DESCRIPTION

Note:

If the RN4020 is operated in a hostless mode (without a microcontroller), set the UART_RX pin to high

via a 10K resistor to reduce power consumption in Deep Sleep mode.