S100 Slave - Memory eMMC


The Memory eMMC Module allows you to endow your Rhomb.io system with a low power, cheap an easy to use memory. This module has a single eMMC chip memory, a flash storage IC that can be used as the system memory. The only thing that you should do is choose the Memory eMMC Module capacity and connect it on your Rhomb.io device.

If during the lifecycle of your device there is a need for more memory, you can upgrade your Rhomb.io device replacing the Memory eMMC Module for another one with more capacity. As simple as that. You can find Rhomb.io eMMC modules with capacities starting at 8GB to a maximum of 128GB.

The next figure show a 3D view of the Memory eMMC Module. Note that the appearance of the module does not change despite the chosen memory capacity.

Memory eMMC Module 3D Top v2.png Memory eMMC Module 3D Bottom v2.png


  • System storage.
  • System booting.

Module specification

The eMMC memories have been designed for a wide range of applications in consumer electronics, mobile phones and tablets among other devices. An eMMC is an embedded non-volatile memory system, comprised of both flash memory and a memory controller, which simplifies the application interface design and frees the host processor from low-level flash memory management.

The Rhomb.io Memory eMMC Module assemblies a single eMMC IC on a standardized Rhomb.io module offering 8GB, 16GB, 32GB, 64GB and 128GB of storage capacity. It uses the SDIO interface in order to maintain the communication with the processor. This eMMC module can be used as the main storage unit on the system, so an operating system can be running over that memory. For doing so, the module should be plugged on the slot number one. This slot is the only one that works at 8 bits on the Rhomb.io standard; the remaining will work using 4 bits.

The next figure shows the Block Diagram for the Memory eMMC Module.

Diagrama de bloques v4.jpg

eMMC (Sandisk/Thosiba) Key Features
Embedded MultiMediaCard memory Ver.5.0 compatible
4/8/16 GB
Data bus width: 1 bit, 4 bit and 8 bit
HS400 mode (200 MHz DDR - up to 400 Mbps)
Op. Voltage: 1.8 V to 2.8 V
Op. Temperature: -25 ºC to +85 ºC



The Memory eMMC Module does not use the GPIOs.

Serial interfaces

The Memory eMMC Module does not use any serial interface.


The next table shows the nomenclature used on the schematic and its corresponding on the rhom standard for the Secure Digital Input Output (SDIO) interfaces. Note that for the SDIO1, only the data signals are used by the IC. This module can be used as 4 or 8 bits of data. If the Memory eMMC Module is the booting device, ensure that is working at 8 bits. On the Rhomb.io motherboards, that means that should be connected to the slot one.

Signal (Rhomb.io) Signal (module) Used by Signal (Rhomb.io) Signal (module) Used by

For more details, look at the module specifications for the Rhomb.io standard.


The module is powered by different power sources, there is a summary on the next table.

Signal (Rhomb.io) Signal (module) Voltage (V) Used
1V8 150mA 1V8 150mA 1.8 Yes
2V8 150mA 2V8 150mA 2.8
VCH 5 No
VSYS 3 - 5.5
Buck8 3.3
Buck9 3.3

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

Other signals

The CLK_32KH, AD_OUT and PWM_INT signals are not used on the Memory eMMC Module. More information regarding these signals can be found at the specifications for the Rhomb.io standard.


Click the image below to download the schematic files.

Bill of materials

Click the image below to download the BOM files.

Fabrication files

Click the image below to download the fabrication files.

Mechanical specifications


Memory eMMC Module Dimensions v1.JPG


  • Precaution against Electrostatic Discharge. When handling Rhomb.io 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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Where to buy

You can purchase this item at the Rhomb website store.

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