8devices Carambola 2

Carambola 2 board

FIXME Please add the installation procedure here.

mtdparts=spi0.0:256k(u-boot)ro,64k(u-boot-env)ro,2048k(kernel),13888k(rootfs),64k(nvram),64k(art)ro,15936k@0x50000(firmware) ... m25p80 spi0.0: found w25q128, expected m25p80 m25p80 spi0.0: w25q128 (16384 Kbytes) 7 cmdlinepart partitions found on MTD device spi0.0

Partition Start End Size Erasesize Name Description
mtd0 0x000000000000 0x000000040000 0x00040000 0x00010000 u-boot
mtd1 0x000000040000 0x000000040000 0x00010000 0x00010000 u-boot-env
mtd2 0x000000050000 0x000000040000 0x00200000 0x00010000 kernel
mtd3 0x000000250000 0x000000FE0000 0x00D90000 0x00010000 rootfs root filesystem
mtd4 0x000000480000 0x000000FE0000 0x00B60000 0x00010000 rootfs_data partition created automatically, ofs=480000, len=B60000
mtd5 0x000000FE0000 0x000000FF0000 0x00010000 0x00010000 nvram
mtd6 0x000000FF0000 0x000001000000 0x00010000 0x00010000 art
mtd7 0x000000050000 0x000001000000 0x00F90000 0x00010000 firmware
Architecture MIPS
Vendor 8devices
bootloader ?
System-On-Chip Atheros AR9331
CPU/Speed MIPS24Kc 400 MHz
Flash size 16 MB NAND-Flash
Wireless 150Mbps WiFi g/n with on-board chip antenna (21 dB output power), U.FL connector
Ethernet 2x 10/100Base-T(X)
USB 1x 2.0 (host), 1x miniUSB (slave)
Serial YES (via miniUSB or RS232 (soldering needed))
LED Standard Ethernet LED's, WIFI LED
Hardware buttons Hardware reset button, GPIO programmable button
Power options miniUSB jack (3.0-3.6 V)
Power consumption ~0.5 Watt
Dimensions mm x mm, grams
  • 802.11 b/g/n, 2.4 GHz, 1×1 SISO, 150MBps max data rate, 21 dB output power
  • U.FL connector or external pin for external an­tenna
  • 16 MB FLASH, 64 MB DDR2 RAM
  • CPU – AR9331, 400 MHz clock speed
  • 28 by 38 mm Size – small and easy to embed
  • Surface mountable
  • Power supply - 3.3 V, power consumption 0.5 W
  • Available interfaces - USB host/slave, serial port, 2 x Ethernet, i2S, SLIC, SPDIF, 23 x GPIO

Serial connection settings:

  • 115200 8N1, no hardware flow control.


Works via the built-in miniUSB port:

apt-get install picocom
picocom -b 115200 /dev/ttyUSB0

Bootstrap HIGH or LOW means that during bootstrap process (first few seconds as device is turned on) these pins need to be in that state. If pins are not in requred state then device will not boot correctly.

Worry free GPIO pins™: If you have some DIY project use GPIO pins 18, 19, 20, 21, 22 and 23 without any worries, these pins are not used during booting. Other GPIO pins are not suitable for use if you don't know exactly what you are doing because they are used during boot process (bootstrap).

LED GPIO LED0 (GPIO0), LED2 (GPIO13) and LED3 (GPIO14) are being used by kernel module “leds_gpio” - You can use them after removing leds_gpio module by rmmod, or removing it permanently from /etc/modules.d

Carambola 2 pinout

Pin mapping (GPIO to SOC to Carambola2 module)

GPIO Carambola Pin AR9331 Pin Input/Output Bootstrap Name Description
0 41 A78 output Must be HIGH during bootstrap Wlan led, LED0 10K pull-down output
1 40 A77 bidirectional Must be HIGH during bootstrap LED1 10K pull-up output, input goes to ground
11 23 B48 input Soft reset / Jumpstart 1K and 100pF input, reset if connected with GND
12 24 A56 input Must be LOW during bootstrap
13 39 B66 output Must be HIGH during bootstrap LED2 / ETH0 LED 10K pull-down output
14 38 A76 bidirectional Must be LOW during bootstrap LED3 / ETH1 LED 10K pull-down output
15 37 B65 bidirectional Must be LOW during bootstrap LED4 10K pull-down output
16 36 A75 bidirectional Must be LOW during bootstrap LED5 10K pull-down output
17 35 B64 output Must be HIGH during bootstrap LED6 10K pull-up output
18 6 A28 bidirectional I/O line number 18
19 5 B23 bidirectional I/O line number 19
20 4 A27 bidirectional I/O line number 20
21 3 B25 bidirectional I/O line number 21
22 2 B24 bidirectional I/O line number 22
23 1 B22 bidirectional I/O line number 23

Bootstrap hardware initialization

AR9331 datasheet mentiones these GPIOs used by hw initialization:

  • GPIO 0 : Crystal frequency of external clock 0=25, 1=40 MHz
  • GPIO 1 : Booting from internal 0=ROM, 1=SPI Flash
  • GPIO 11: 0=General JTAG, 1=CPU ICE
  • GPIO 12/28 : external memory type (00=SDR, 01=DDR, 10=DDR2)
  • GPIO 13: USB mode 0=device, 1=host
  • GPIO 16: Download firmware from 0=USB, 1=MDIO
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  • Last modified: 2024/02/12 08:58
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