[Review] Lemaker’s Guitar board

Lemaker, well known for making the BananaPi and BananaPro boards, have now 3 more boards, named after musical instruments : Guitar, Bass, Piano. In this article, I’m reviewing the Guitar board Lemaker kindly sent to me.

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The Guitar board comes in a 204 pins SODIMM form factor, just like the Raspberry Pi Compute module. This « Guitar core board » is stuffed with minimal components : SoC, RAM, 8GB NAND and PMU (Power Management Unit).

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First, it’s important to note Guitar board changed architecture from BananaPi / BananaPro : instead of a Allwinner SoC (A20 in these cases), Guitar board now uses a S500 SoC from Actions Semiconductors. The S500 SoC is a very capable chip, featuring a Quad-Core Cortex-A9R4 processor with NEON SIMD co-processor and 3D GPU PowerVR SGX544. It could do Ultra HD (2k – 4k) video playback, 1080@60fps video encoding, has MIPI / DSI / LCD / HDMI interfaces, USB2.0 / 3.0 and supports up to 2Gb DDR3 RAM.

While this form factor is not easy to work with, Lemaker also provides what they call the « Guitar base board », featuring the inputs/outputs absent from the core board : HDMI, audio / composite video out, mic, 3xUSB, display and camera connectors (compatible with BananaPi / Pro addons), 40 pins GPIO (Raspberry Pi compatible), an external 3.7v battery connector, Wifi, 100mb/s ethernet, 2 buttons and 3 LEDs.

Edit : I’ve been told on Reddit the final revision of the Base board should have GigaBit ethernet instead of the actual 10/100Mb/s. Very nice !

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Hardware Specifications

Guitar core board

Hardware Specification of LeMaker Guitar TM
SoC Actions S500
CPU ARM® Cortex™-A9R4 Quad-Core up to 1.3 GHz (ARM v7 instruction set)
GPU Imagination PowerVR SGX544, Support OpenGL-ES 1.1 and 2.0, OpenVG 1.0.1
RAM 1 GB DDR3 SDRAM (option 2GB DDR3 SDRAM)
PMU ATC2603C (Integrated Audio Codec etc)
Features
Storage 8GB eMMC (Options 4GB/8GB/16GB/32GB)on board storge
Video 4K HD video decoding
1080P@60fps HD video encoding
Supports MPEG-4, H.263, H.264 and other mainstream video formats
LCD Interface Select LVDS / RGB / MIPI
Expansion Interface 204 Pins standard DDR3 SODIMM
OS Support Android 5.0 / Linux
Appearance characteristic
Sizes 67.6mm x 42.2mm
Weight 10g

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Guitar base board

Hardware Specification of LeMaker Guitar TM Base Board Rev.B
Sorage MicroSD Card slot
Ethernet Port 10/100Mbps
Wireless Wi-Fi 802.11 b/g/n 2.4GHz
Bluetooth 4.0
1 x IR receiver
USB 2 x USB 2.0 HOST
1 x MicroUSB 3.0 HOST & DEVICE
Display 1 x HDMI 1.4(Type A – full), supports up to 4096*2048@30HZ
1 x LVDS-DSI for raw LCD panels (up to 4096 x 2048)
Composite video output (via 3.5 mm TRRS jack shared with Analog audio out)
Audio HDMI output
Analog audio (via 3.5 mm TRRS jack shared with composite video out)
I2S audio output (also available as audio input)
On board MIC input
Camera 1 x MIPI-CSI
1 x Parallel 8-bit camera interface
EXPANSION INTERFACE 40 Pins Header : 28×GPIO, some of which can be used for specific functions including UART, I2C, SPI, PWM, I2S
SODIMM 204 Pin Connector : board
Debug COM : debug
LED 1 x Power status LED (red)
1 x User defined LED1 (green)
1 x User defined LED2 (blue)
Button Power Button : Button Power on/off
Reset Button : Button System reset
Power Source 12V@2A, Plug   specification is inner diameter 2.1mm and outer diameter 5.5mm
Appearance characteristic
Sizes 88mm x 88mm
Weight 58g

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It appears LeMaker plans to release different base boards for various purposes. I’m impatient to learn more about that.

GPIO header pinout

The Guitar base board features a 40 pins GPIO header, compatible with Banana Pi / Pro and Raspberry Pi and featuring UART, I2C, SPI, PWM, I2S.

Important : the GPIOs pins use 3.3v logic !

030051ynjegkzjexpjezctNote : I’ve been contacted by LeMaker, who says the B revision I got has little errors on the GPIO connector, and is not completely compatible with Banana / Raspberry. It has been corrected in the later mass production revision.

Here is the GPIO pinout of the 1.1 revision :

Pin on Board Pin on S500 Functions Pin on Board Pin on S500 Functions
J4-01 \ VCC(3.3V) J4-21 GPIOC25 SPI0_MOSI/NOR_A15/TWI3_SDATA/
PCM0_SYNC
J4-02 \ 5V J4-22 GPIOC5 DSI_CN/SD1_D0/LCD0_D0/
J4-03 GPIOE3 TWI2_SDA J4-23 GPIOC22 SPI0_SCLK/TWI3_SCK/NOR_A12/
PCM0_CLK
J4-04 \ 5V J4-24 GPIOB19 OAN/LCD0_D15
J4-05 GPIOE2 TWI2_SCK J4-25 \ GND
J4-06 \ GND J4-26 GPIOC24 SPI0_MISO/NOR_A14/I2S_MCLK1/
PCM1_IN/PCM0_IN
J4-07 GPIOB18 OAP/LCD0_D19 J4-27 GPIOB16 OBP/LCD0_D21
J4-08 GPIOC27 UART0_TX/UART2_TX/SPI1_SS/
TWI0_SCLK/SPDIF/PCM1_OUT/I2S_LRCLK1
J4-28 GPIOB14 OBN/LCD0_D20
J4-09 \ GND J4-29 GPIOB15 OCN/LCD0_D22
J4-10 GPIOC26 UART0_RX/UART2_RX/SPI1_MISO/
TWI0_SDATA/PCM1_IN/I2S_LRCLK1
J4-30 \ GND
J4-11 GPIOC0 DSI_DP3/SD1_CLK/LCD0_D16 J4-31 GPIOB10 OEP/LCD0_DCLK0
J4-12 GPIOB8 PWM3/SD0_CLK/KS_OUT1 J4-32 GPIOB13 ODN/LCD0_LDE0
J4-13 GPIOC1 DSI_DN3/SD1_D3/GPIOC1/LCD0_D9 J4-33 GPIOB0 I2S_BCLK1/PCM0_OUT/NOR_A21
J4-14 \ GND J4-34 \ GND
J4-15 GPIOC4 DSI_CP/SD1_D1/LCD0_D1 J4-35 GPIOB1 I2S_LRCLK1/PCM0_CLK/NOR_A22
J4-16 GPIOA25 /SIRQ1 J4-36 GPIOA28 I2S_BCLK0/PCM0_IN/NOR_A17
J4-17 \ VCC(3.3V) J4-37 GPIOB2 I2S_MCLK1/PCM0_SYNC/NOR_A23
J4-18 GPIOB9 KS_OUT2/UART5_TX/SD0_D18/
NOR_A11/PWM2/SENS1_HSYNC
J4-38 GPIOA31 I2S_D1/NOR_A20
J4-19 GPIOC23 SPI0_SS/NOR_A13/I2S_LRCKL1/
PCM1_OUT/PCM0_OUT
J4-39 \ GND
J4-20 \ GND J4-40 GPIOA27 I2S_D0/NOR_A16

When I’m writing this article, I still don’t know if the pre-installed OS has scripts to play with the GPIO already.

204 pins SODIMM connector pinout

Here is the pinout of the Guitar core board 204 pins SODIMM connector :

sodimmLCD connector pinout

Pin on Board Pin definition Pin on Board Pin definition
CON1-01 5V CON1-22 GND
CON1-02 TWI1_SDA COM1-23 LVDS_RXEC-
CON1-03 5V CON1-24 GND
CON1-04 TWI1-SCK CON1-25 LVDS_RXE3+
CON1-05 GND CON1-26 GND
CON1-06 TP_PWD/RST(B3) CON1-27 LVDS_RXE3-
CON1-07 LCD_VCC_EN(B4) CON1-28 GND
CON1-08 LVDS_RXO1- CON1-29 \
CON1-9 LVDS_RXE0+ CON1-30 ADC_COM
CON1-10 LED_PWM CON1-31 ADC0
CON1-11 LVDS_RXE0- CON1-32 FMINR
CON1-12 GPIOA24/SIRQ0 CON1-33 GND
CON1-13 LVDS_RXE1+ CON1-34 MIPI_DSI_DP0
CON1-14 GND CON1-35 MIPI_DSI_DN0
CON1-15 LVDS_RXE1- CON1-36 MIPI_DSI_DP2
CON1-16 GND CON1-37 MIPI_DSI_DN2
CON1-17 LVDS_RXE2+ CON1-38 GND
CON1-18 GND CON1-39 \
CON1-19 LVDS_RXE2- CON1-40 IR
CON1-20 \ CON1-41 GND
CON1-21 LVDS_RXEC+ CON1-42 GND

Software

The Guitar core board comes with Ubuntu 12.04 pre-installed in the 8GB NAND. It boots and works out the box. However, there are a few bugs in this early release :

  • I could not find how to change the display resolution, which is set on 1024*600 on a 1920*1080 display,
  • my KVM switch doesn’t work at all, but I expected this,
  • the root partition is not expanded, so it is running out of free space very quickly. There’s 5.1Gb free in an unused partition.
  • I think sound is not working (at least on HDMI)

Other than that, everything is running well and smooth. My Rapoo keyboard + touchpad, the ethernet and wifi are working out of the box, and the wifi range is very good (better than some laptops).

According to Lemaker, switching to Android 5.0 is very easy, but I didn’t test it : I’m not interested in Android on these boards, I prefer to keep a real Linux.

Conclusion

Lemaker did a very good job with these Guitar boards. While I don’t know exactly their selling price, the Guitar core board is advertised to be a 25$ board. This is very interesting, and is competing directly with the Raspberry Pi, when Bananas are more expensive (35-45$).

The Guitar is a big step forward from Banana / Raspberry / whatever boards, with quad-core, fast RAM, NAND, wifi, battery charging circuit, etc…

While the SODIMM form factor is not really easy to work with, this is the key to build powerfull and professional devices.

Even if there are a few bugs remaining, I’m sure LeMaker team will solve these very quick. They are very talented people, and I bet they will get even more momentum with this new boards line. One a side note, it’s good to see a company dropping the Fruit Pi naming scheme. I’m glad to see this team taking the right direction, and becoming very experienced since the Banana Pi days…

About Captain Stouf

Spécialiste en systèmes informatiques, Développeur matériel et logiciel, Inventeur, Maker : électronique, Systems on Chip, micro-controlleurs, Internet of Things, Modélisation / Scan / Impression 3D, Imagerie...

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