Datasheet

RN4678
DS50002519D-page 12  2016-2019 Microchip Technology Inc.
2.8 LED Driver
The RN4678 has a dedicated LED driver and the LED
can be connected directly to this pin as shown in
Figure 2-7.
The maximum current sourcing for the LED is 5 mA.
The brightness of this LED can be configured via an
ASCII command.
FIGURE 2-7: LED DRIVER
The following are the LED status indications. Each indi-
cation is a configurable flashing sequence:
• Standby
• Link Back
• Low Battery
• Inquiry
• Link
2.9 Host MCU Interface over UART
Figure 2-8 illustrates an example of UART interface
with host MCU and power scheme using 3.3V to the
V
DD. From the LDO33_O pin, voltage can be routed to
the VDD_IO pin and the external circuitry including the
MCU. This power scheme ensures that the RN4678
and the MCU I/O voltages are compatible.
FIGURE 2-8: POWER AND MCU INTERFACE EXAMPLE FOR RN4678
Note 1: Ensure that VDD_IO and MCU VDD voltages are compatible.
2: The control and indication ports are configurable.
RN4678518
Module
LDO33_O
LED1
Note: The internal 3.3V LDO current source
must not exceed 50 mA (maximum).
(3.3V to 4.2V)
10uF
BAT_IN
LDO33_O
VDD_IO
(Note:1)
LDO18_O
LED
P1_5/STATUS_IND_1
P0_4/UART_TX_IND/STATUS_IND_2
RN4678
MODULE
SW_BTN
WAKE_UP
RST_N
P3_4
P3_7
P3_2
P3_3
P1_7/CTS
P0_0/RTS
P3_1
P0_5
TXD
RXD
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
RTS
CTS
TX
RX
HOST
MCU
VDD
System Configuration
3.3V
P2_0 P2_4 EAN
Note:2