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.
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).
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 !
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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- Actions S500 SoC
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- DDR3 RAM
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- NAND chip
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- Power Management Unit (PMU)
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- Video output selector swicth
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- I don’t know what this dip-switch is used for…
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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- Front side
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- Back side
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- MicroSD slot, HDMI, USB 3.0, 2xUSB 2.0
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- 12v Power connector, audio / video out, mic, buttons, debug UART, 100mb/s ethernet
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- Wifi module
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- Wifi antenna
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- 3.7v external battery connector
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- Closer view of audio / video output, mic, buttons, LEDs and debug UART
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 !
Note : 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 :
LCD 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.
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- Ubuntu desktop
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- Wifi is working out of the box
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- Some network details
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- The /root/ partition has not been expanded, we have 5.1Gb available on a second partition
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- NAND benchmark, not bad at all
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…
