Renesas Synergy™ Platform
Application Example for Cloud Connectivity (AE-CLOUD2)
R12UM0033EU0100 Rev.1.00
Page 11 of 48
Sep 5, 2018
4.2.1 Power Supply Options
The power supply source is the J9 - USB Micro-B connector providing 5 V and up to 500 mA of power.
Figure 9 Power Supply Management
Note that the Schottky diodes provided are in series with the power source. This protects them from overload in case
both are connected and one has higher voltage than the other.
4.2.2 Power-up Behavior
Upon power up, the MCU is idle until its RESET pin registers transition to logic 1. At this point, the MCU hardware
samples the logic level of the MD pin. The MD pin level determines if the MCU will enter ‘Factory Boot Mode’. In this
mode, the MCU executes an internal firmware code that initializes the USB interface and prepares the device to
communicate with utilities that can update the content of its memory.
The state of the MD pin at startup is defined by S2. If the button is pressed at the time of the RESET signal, then the
factory bootloader will execute on startup. If S2 is not pressed at the time of the RESET signal, then the MCU will
execute the code previously loaded to the MCU code flash memory.
