Deimos v1.0

This sheet shows the documentation for the Deimos board.

Preliminary version, use only for data updating or corrections.


The Deimos board is a certified PCB that allows to create electronics devices using exclusively standard modules. It combines the ease-of-use standard modules with a reduced form factor PCB, and it has been developed for the Internet of Things (IoT) bearing in mind the fast product development. The board includes also a battery management circuit bringing to the designer the capacity to made portable devices.

The next figures show a 3D view for the Phobos board.

Deimos 3D Top v1.png Deimos 3D Bottom v1.png

As a summary, the following table indicates the main features:

Phobos features
USB 1 USB type B
Expansion headers 40 pines modules 1 Master Module slot
2 Generic Module slots


  • Internet of Things
  • Wearables
  • Makers
  • Fast prototyping

Board specifications

The Deimos board it has been designed for working only with standard modules, so a core is not needed. Three standard modules holders are available, one for the master module and two for the slaves. That brings simplicity and speed up the product designing and development stage.

There are two different ways to empower the system: using the micro-USB connector or a battery. The PCB also includes a Lithium battery charge management controller bringing the capacity to work independently of the power supply.

As a summary, here are the key features for the Phobos board:

  • Capacity for holding two modules: master and slaves
  • There is no need for a Core
  • Compatibility with all the modules
  • Fast prototyping
  • USB connector for data and power supply
  • In-circuit battery management
  • Small form factor

The block diagram shows the parts that make it possible.

Deimos Block Diagram v1.png

The following figure identify the main parts of the board. The most important parts will be explained with more details in the next sections.

Deimos Description Top v1.png Deimos Description Bottom v1.png Core

The Deimos board has no core sockets. modules

Lots of modules focused in different areas such as communications, sensing or storage, are available. The Deimos board allows to connect one master module and two slave modules. Look at here [Añadir enlace a la tienda, sección modulos] to chose the desired modules to convert your Deimos in the device you want.


Only one memory options is available in the Deimos board: use Memory eMMCXX Modules.



There is available one USB 2.0 port on the Deimos board and it work as a host for the master module. It is also three headers with a total of 40 pins that allow to access to some master module signals. The following table shows the pinout of the headers.

Pin Function
1 1V8
2 2V8
3 3V3
6 IO16 (SPI SS)
10 SCL0
11 SDA0
12 IO32 (1-wire)
Pin Function
1 TXD1
2 RXD1
3 TXD0
4 RXD0
5 AD0
6 AD1
7 AD2
8 AD3
9 IO0
10 IO1
11 IO2
12 IO3
13 IO4
14 IO5
15 IO6
16 IO7
Pin Function
1 IO8
2 IO9
3 IO10
4 IO11
5 IO12
6 IO13
7 IO14
8 IO15
12 GND

Deimos Wired v1.png


The Deimos board has nos wireless interfaces.


The Deimos board has nos audio and video interfaces.

LEDs and Button

The two available LEDs onboard are intended to indicate the battery charging status. The orange LED will bright when the USB charging source is connected in order to indicate that the battery is being charging. When the process finishes, the orange LED turns off and the green one turns on. When the USB cabled is disconected, the two LEDs turns off. In any case, if the battery is disconnected, the LEDs will not work.

There is no buttons assembled on the Deimos board.

Deimos LEDsandButtons v1.png


Master module auxialiary connectors

The following table summarizes the standard signals of the master module socket and where they are used in the Deimos. These signals may not have functionality depending of the microcontrolled plugged on the board.

Pin Signal Used by Pin Signal Used by
1 IO47, SDA1 Slave Module 2 SPI_INT 50 IO0 H2 pin 9, Slave Module 1 GPIO0
2 IO46, SCL1 49 IO1 H2 pin 10, Slave Module 1 GPIO1
3 IO45, LPUART.RX/RXD2, SPIFI_IO3 48 IO2 H2 pin 11, Slave Module 1 GPIO2
4 IO44, LOPUART.TX/TX2, SPIFI_IO2 47 IO3 H2 pin 12, Slave Module 1 GPIO3
5 IO43, SPI1_MOSI, SPIFI_IO1 46 IO4 H2 pin 13, Slave Module 1 GPIO4
6 IO42, SPI1_MISO, SPIFI_IO2 45 IO5 H2 pin 14, Slave Module 1 GPIO5
7 IO41, SPI1_CLK, SPIFI_CLK 44 IO6 H2 pin 15, Slave Module 1 GPIO6
8 IO40, SPI1_SS, SPIFI_CS 43 IO7 H2 pin 16, Slave Module 1 GPIO7
10 IO39, TMS/SWDIO 41 IO8 H3 pin 1, Slave Module 2 GPIO0
11 IO38, TCK/SWCLK 40 IO9 H3 pin 2, Slave Module 2 GPIO1
12 IO37, TDO/SWO 39 IO19 H3 pin 3, Slave Module 2 GPIO2
13 IO36, TDI 38 IO11 H3 pin 4, Slave Module 2 GPIO3
14 1V8 1.8 V 37 IO12 H3 pin 5, Slave Module 2 GPIO4
15 2V8 2.8 V 36 IO13 H3 pin 6, Slave Module 2 GPIO5
16 35 IO14 H3 pin 7, Slave Module 2 GPIO6
17 3V3 3.3 V 34 IO15 H3 pin 8, Slave Module 2 GPIO7
19 32
20 VIO_ REF H3 pin 9, Slaves Module VDDIO_MOD 31
22 GND GND 29 AD0 H2 pin 5, Slave Modules AD_OUT
23 AD14 28 AD1 H2 pin 6
24 AD13 27 AD2 H2 pin 7
25 AD12 26 AD3 H2 pin 8
1 AD11 50 AD4
2 AD10 59 AD5
3 AD9 48 AD6
4 AD8 47 AD7
6 IO35, TRST Slave Module 2 I2C_INT 45 RXD0 H2 pin 4, Slave Module 1 UART0_RXD
7 IO34, CAN1_RX Slave Module 1 SPI_INT 44 TXD0 H2 pin 3, Slave Module 1 UART0_TXD
8 IO33, CAN1_TX Slave Module 1 I2C_INT 43 RXD1 H2 pin 2, Slave Module 2 UART0_RXD
9 IO32, 1-WIRE/SWP H1 pin 12 42 TXD1 H2 pin 1, Slave Module 2 UART0_TXD
10 USB2_P Slave Module 1 USB 41 SDA0 H1 pin 11, Slave Modules I2C_SDA
11 USB2_N 40 SCL0 H1 pin 10, Slave Modules I2C_SCL
12 USB_ID 39 SPI0_MOSI H1 pin 9, Slave Modules SPI_MOSI
13 CLK_32KHz Slave Modules CLK_32KH 38 SPI0_MISO H1 pin 8, Slave Modules SPI_MISO
14 BAT_RTC 37 SPI0_SCK H1 pin 7, Slave Modules SPI_SCK
15 VBAT VBAT 36 SPI0_SS Slave Module 1 SPI_SS
16 35 RESET H1 pin 5
17 34 GND GND
18 IO31, SDIO0_DATA1 Slave Module 1 SDIO0_DATA1 33 IO16, I2S_SDI H1 pin 6 (SPI SS)
19 IO30, SDIO0_DATA0 Slave Module 1 SDIO0_DATA0 32 IO17, I2S_SDO, SDIO1_DATA1 Slave Module 2 SDIO1_DATA1
20 IO29, SDIO0_CLK Slave Module 1 SDIO0_CLK 31 IO18, I2S_SCLK, SDIO1_DATA0 Slave Module 2 SDIO1_DATA0
21 IO28, SDIO0_CDN Slave Module 1 SDIO0_CLK 30 IO19, I2S_LRCK, SDIO1_CLK Slave Module 2 SDIO1_CLK
22 IO27, SDIO0_CMD Slave Module 1 SDIO0_CMD 29 IO20, I2S_CDCLK, SDIO1_CDN Slave Module 2 SDIO1_CDN
23 IO26, SDIO0_DATA3 Slave Module 1 SDIO0_DATA3 28 IO21, CAN2_RX, SDIO1_CMD Slave Module 2 SDIO_CMD
24 IO25, SDIO0_DATA2 Slave Module 1 SDIO0_DATA2 27 IO22, CAN2_RX, SDIO1_DATA3 Slave Module 2 SDIO1_DATA3
25 IO24, DAC1 26 IO23, DAC0, SDIO1_DATA2 Slave Module 2 SDIO1_DATA2

Regarding the serial interfaces, three issues should be mentioned. The USB data lines comes from the micro USB type B connector to the master socket. Only the Slave Module 1 can comunicate with the Master Module via USB. For the I2C interface, the board provides two pull-ups resistors (R4 and R5). Those pull-ups are defined as normally not connected to the supply. If it is needed to use them, the user should solder the onboard solder jumper that will connect the power supply with the resistors.

For more details, look at the specifications for the standard.


The Deimos board provides the needed voltages for the sockets. For doing so, Low Dropout Regulators (LDO) has been included for supplying the "1V8 150mA", "2V8 150mA", "Buck8" and "Buck9" voltages. The "VSYS" voltage is switched in between 5V and Vbat (battery voltage) according to the following cases:

  • There is battery but the USB charger is not connected: VSYS = VBAT
  • There is battery and the USB charger is connected: VSYS = 5V (according to the USB standard)
  • There is no battery and the USB charger is connected: VSYS = 5V (according to the USB standard)
  • There is no battery and the USB charger is not connected: VSYS = 0V

As per the above, the Deimos board can work both connected constantly to a USB 5V source or with a battery. In this last case, only single cell Li-Po or Li-Ion batteries are supported. The charging rate it is fixed to 100mA.

Getting started


Bill of materials

Fabrication files

Mechanical specifications


Deimos Dimensions v1.png


  • Precaution against Electrostatic Discharge. When handling products, ensure that the environment is protected against static electricity. Follow the next recommendations:
  1. The users should wear anti-static clothing and use earth band when manipulating the device.
  2. All objects that come in direct contact with devices should be made of materials that do not produce static electricity that would cause damage.
  3. Equipment and work table must be earthed.
  4. Ionizer is recommended to remove electron charge.
  • Contamination. Be sure to use semiconductor products in the environment that may not be exposed to dust or dirt adhesion.
  • Temperature/Humidity. Semiconductor devices are sensitive to environment temperature and humidity. High temperature or humidity may deteriorate semiconductor devices characteristics. Therefore avoid storage or usage in such conditions.
  • Mechanical Shock. Care should be exercised not to apply excessive mechanical shock or force on the connectors and semiconductors devices.
  • Chemical. Do not expose semiconductor device to chemical because reaction to chemical may cause deterioration of device characteristics.
  • Light Protection. In case of non-EMC (Epoxy Molding Compound) package, do not expose semiconductor IC to strong light. It may cause devices malfunction. Some special products which utilize the light or have security function are excepted from this specification.
  • Radioactive, Cosmic and X-ray. Semiconductor devices can be influenced by radioactive, cosmic ray or X-ray. Radioactive, cosmic and X-ray may cause soft error during device operation. Therefore semiconductor devices must be shielded under environment that may be exposed to radioactive, cosmic ray or X-ray.
  • EMS (Electromagnetic Susceptibility). Note that semiconductor devices characteristics may be affected by strong electromagnetic waves or magnetic field during operation.

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