Datasheet

 2016-2019 Microchip Technology Inc. DS50002519D-page 7
RN4678
2.0 APPLICATION INFORMATION
2.1 Module Configuration
For the I/O pins, P2_0, P2_4 and EAN, place the
RN4678 into Operating mode. Each of these pins have
internal pull-up and allow configuration settings and
firmware to be updated from UART.
Ta bl e 2-1 provides
system configuration details.
2.2 Flow Control
Flow control is enabled by default on the RN4678
module. With the flow control enabled, the RTS and
CTS lines need to be connected to the corresponding
lines for the module to operate. To pause data flow from
the RN4678, the CTS (RN4678 input pin) must be
pulled high. The RN4678 pulls the RTS pin (output pin)
low to indicate that it can accept data.
2.3 Control and Indication I/O Pins
The GPIO pins of the RN4678 module can be
configured to different functions using the ASCII
command interface.
Tab le 2-2 shows the various pins
in the RN4678 module that are available for
configuration and their default configuration settings.
Table 2-3 provides details on each of the functions
available.
TABLE 2-2: CONTROL AND INDICATION I/O PIN ASSIGNMENTS
TABLE 2-3: CONFIGURABLE FUNCTIONS AND DESCRIPTIONS
TABLE 2-1: SYSTEM CONFIGURATION SETTINGS
P2_0 P2_4 EAN Operational Mode
Low Low High Write FLASH
Low High Low Write EEPROM and Test mode
High High Low Normal Operational/Application mode
PIN Symbol Default Configuration
P0_0 UART_RTS
(1,2)
P0_5 N/C
P1_7 UART_CTS
(1,2)
P3_1 INQUIRY CONTROL
P3_2 LINK_DROP_CONTROL (DISCONNECT)
P3_3 UART_RX_IND
P3_4 PAIRING_KEY
P3_7 LOW_BATTERY_IND
Note 1: The RTS pin can only be assigned to P0_0 and the CTS pin can only be assigned to P1_7.
2: The RTS and CTS pins can be configured as GPIOs if flow control is disabled.
Function Name Description
Low Battery Indication Pin output goes low when the battery level is below a specified level. Default
battery low indication voltage level is 3.4V
RSSI Indication Use this pin to indicate the quality of the link based on the RSSI level. If the
RSSI level is lower than the specified values, then the RSSI indication pin
goes low.
Link Drop Control Use this pin to force the module to drop the current BLE link with a peer
device. Pulling the Link Drop pin low forces to disconnect. The pin must be
pulled low for at least 10 ms.