User Manual

P A G E 12
E a s y P I C v 8 M a n u a l
N O T EThe MCLR/GPIO pin should be set via the CONFIG bits as MCLR, and the MCLR switch
should be in the RESET (down) position, in order for the RESET button to work.
Power redundancy and uninterrupted
power supply (UPS)
The PSU module supports power supply redundancy: it will automatically switch to
the most appropriate power source if one of the connected power sources fails or
becomes disconnected. The power supply redundancy also allows for an uninterrupted
operation (e.g. UPS functionality, the battery will still provide power if the USB cable is
removed, without resetting the MCU during the transition period).
Powering up the development board
Two touch-sensitive buttons are used to power up and reset the EasyPIC v8
development board. These capacitive buttons are processed by two AT42QT1011,
digital burst mode charge-transfer sensors, specifi cally designed for human-machine
interfaces (HMI), from Microchip. The AT42QT1011 allows very responsive and reliable
touch detection for the connected button pad.
As soon as a valid power source is connected, the development board will enter the
Stand-By mode. When the capacitive POWER button is pressed, the PSU module will
start distributing the power to the rest of the development board. This is indicated by
the POWER LED indicator, located on the PSU module itself.
Right under the POWER LED, there is a CHARGE LED, indicating the charging status of
the Li-Po/Li-Ion single cell battery, if connected. The complete battery power supply
section, including the battery charger circuit, is explained in the respective chapter
of this manual.
Below the POWER capacitive button (1), there is a RESET capacitive button (2) which
is not entirely power-related, but it has a similar function: it is routed to the MCLR
pin of the MCU, allowing the RESET function to be performed. However, since low pin-
count MCUs often use multiple functions on the same pin, the development board
off ers a choice in the form of a DIP switch (3) labeled as MCLR, which allows to specify
whether the MCLR/GPIO pin should be used as GPIO or it should be connected to the
RESET circuit of the development board:
P A G E 12
E a s y P I C v 8 M a n u a l
P O W E R S U P P L Y
Dual power supply
EasyPIC v8 development board supports both 3.3V and 5V power supply on a single
board. Advanced PSU module provides the possibility to chose power supply for board
and host MCU, between 3.3V (default) and 5V. This setting can be easily confi gured
from CODEGRIP Suite, and this feature greatly increases the number of supported
MCUs.
GPIO (up): if the MCU uses the MCLR/GPIO pin as the GPIO
RESET (down): if the MCU uses the MCLR/GPIO pin as the MCLR (RESET)