OLIMEX© 2015
A13-OLinuXino-MICRO user's manual
CHAPTER 5: CONTROL CIRCUITY
5. Introduction to the chapter
Here you can find information about reset circuit and quartz crystals locations, the power supply
circuit is discussed.
5.1 Reset
The reset line is handled by MCP130T-300-I. This is a voltage supervisory device designed to keep
a microcontroller in reset until the system voltage has reached the proper level and stabilized. It also
operates as protection from brown-out conditions when the supply voltage drops below a safe
operating level. The reset goes to processor pin 195. The reset circuit is connected to button RESET,
which means pressing RESET would perform a hardware reset on the board.
5.2 Clock
24 MHz quartz crystal Q1 is connected to pins 91 and 92 of the A13 processor.
5.3 Power supply circuit
The 5V power supply is handled by three voltage regulators for the 1.2V, 1.5V and 3.3V power
lines.
The board can be powered from the USB_OTG connector. Note that powering from the USB limits
the current available for peripheral devices (like mouse, keyboard, LCD display, UEXT modules,
etc.).
Page 14 of 29
