User manual

CHAPTER 6: CONNECTORS AND PINOUT

6. Introduction to the chapter

In this chapter are presented the connectors that can be found on the board all together with their

pinout and notes about them. Jumpers functions are described. Notes and info on specific

peripherals are presented. Notes regarding the interfaces are given.

6.1 UART0 interface

The UART0 interface might be used for serial communication between the board and a personal

computer by default. In case of video output problem a cable might provide needed feedback and

greatly reduce the efforts needed to repair the board or to adjust the software setting.

Note that by default only UART0 is defined as a port suitable for serial debug. You can use our

USB-SERIAL-CABLE-F for debugging.

Consider table below when connecting the USB-SERIAL-CABLE-F according to the wire color

code. The RX line of the cable (GREEN wire) should go to TX line of the target board; the TX line

of the cable (RED wire) should go to the RX line of the target board. The BLUE wire should go to

the target's GND line.

UART0

Pin # Signal name Processor pin

1 UART0-TX A7

2 UART0-RX B7

3 GND -POWER CIRCUIT-

6.2 MicroSD card connector

The micro SD card slot is primarily used for booting the operating system.

The board works with micro SDHC cards up to 32GB of storage.

As a general precaution be careful with the SD cards you purchase. There is a big percentage of

fake cards due to the low effort required to counterfeit popular brands and the big demand for SD

cards worldwide. When in doubt – try the same operation with another card from another brand.

Olimex sells microSD cards with Linux or Android images, that have been tested – please refer to

chapter “2.2 Requirements”. Of course, if you already have a large enough microSD card you can

download the official Linux image from the wiki pages: https://www.olimex.com/wiki/A20-

OLinuXino-LIME2.

When removing the card, please make sure that you release it from the connector by pushing and

NOT by pulling the card directly (this can damage both the connector and the microSD card).

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