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OLIMEX© 2014
A13-OLinuXino 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 the AXP209 (which is an enhanced single cell Li-battery and power
system management IC that goes together with the Allwinner processor) and goes to processor pin
159 via R4(47k). The reset circuit is connected to button RESET, which means pressing RESET
would perform a hardware reset on the board.
5.2 Clocks
24 MHz quartz crystal Q1 is connected to pins 91 and 92 of the A13 processor.
12 MHz quartz crystal Q2 is found at pins 6 and 7 of the GL850G (the USB controller).
32 768 kHz (RTC clock) quartz crystal Q3 is found connected to pins 1 and 2 of the
RTC_MODULE (PCF8563T)
5.3 Power supply circuit
The power supply is handled mainly by AXP209 power management system, an Allwinner chip that
goes together with the A13 processor. The power supply circuit of A13-OLinuXino allows flexible
input supply from 6V to 16V. The minimum amperage suggested is 1A, and this threshold would
rise if using all the three USB-HOSTs, a lot of GPIOs and LCD_con.
The board can also be powered by 3.7V Li-Po battery retaining its functionality or by USB (limiting
the use of peripherals.
Important! Avoid disconnecting the power supply while Android or Linux is running, since that
might corrupt the NAN memory (and the operating system files) and you will need to install the OS
again (for Android install instructions check chapter 2.6. Hold the PWR_BUT and then navigate to
shut down before disconnecting the supply.
Page 20 of 37
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