LinkSprite pcDuino3 Nano

The LinkSprite pcDuino v3 Nano is an A20 development board with Arduino-compatible headers.

= Identification =

A white, credit-card-sized PCB with an A20 chip. "PCDUINO_NANO" is marked on the board to the right of the A20.

= Sunxi support =

Current status
The pcDuino3 Nano is supported by the mainline U-Boot and kernel; it's not supported by the legacy sunxi U-Boot or kernel.

Images
The Ubuntu 14 image that LinkSprite provides uses a modified linux-sunxi 3.4 kernel. Their patches and build scripts are available on GitHub.

The most important modification is in the GMAC driver, to set the GMAC_TX_DELAY parameter to 3. This adjusts the relative timing of the clock and data signals to the PHY in order to compensate for differing trace lengths on the PCB (details; the Banana Pi has the same problem). Without this modification, the Ethernet port will work at 100Mbit but not at 1000Mbit. Upstream U-Boot now sets this parameter itself, so the kernel patch isn't needed any more (patch).

In the meantime Armbian also supports the pcDuino3 Nano with Debian Wheezy, Jessie or Ubuntu Trusty and with both kernel 3.4.x and 4.1.x (including SoC temp fixes).

Mainline U-Boot
For building mainline u-boot, use the Linksprite_pcDuino3_Nano target. (Patch should be merged in U-Boot v2015.04.)

Mainline kernel
Use the sun7i-a20-pcduino3-nano.dtb device-tree file for the mainline kernel. (Patch should be merged in Linux 4.1.)

= Tips, Tricks, Caveats =

SATA power connector
The pcDuino3's SATA power connector uses a JST XH 2.5mm header and is compatible to the Cubieboards but not to the same connector Banana Pi/Pro/M1+ and Orange Pis are using (there 5V/GND is inversed)

FEL mode
The "UBOOT" button triggers FEL mode.

= Adding a serial port =



Locating the UARTs
The pcDuino3 Nano provides access to two of the A20's UARTs. See the UART howto for more details.

The 3-pin header labelled "UART" sticking out from the side of the board is the A20's UART0. Pin 1 (with a square pad, closest to the IR receiver) is RX, pin 2 is ground, pin 3 is TX.

UART2 is available on the Arduino-style J11 connector. Pin 1 (closest to the Ethernet socket) is RX, and pin 2 is TX. Ground is available on pin 7 of J8.

Note that the labelling in LinkSprite's diagram is a bit confusing -- UART2 is described from the A20's point of view but UART0 from the serial cable's point of view, i.e. RX and TX are reversed for UART0.

The position of UART0 makes it samewhat difficult/impossible to use some Arduino Add-ons with the board (see the gallery below for an example with a breadboard breakoutboard)

= Pictures =

= Also known as =

This device has not been rebadged.

= See also =


 * LinkSprite pcDuino
 * LinkSprite pcDuino V2
 * LinkSprite pcDuino V3
 * Schematic
 * Diagram of pcDuino v3 Nano connectors and header pinouts
 * LinkSprite's pcDuino kernel repository on GitHub
 * pcDuino3 Nano ubuntu and android images