Datasheet

 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.