S100 Master - Duino Uno


The S100 Master - Duino Uno is a certified Rhomb.io module that contains the ATmega328P microcontroller, the IC in which the popular Arduino/Genuino Uno/Pro board is based. This IC is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture.

The module allows to program the microcontroller by using the Arduino IDE as it were a genuine Arduino/Genuino Uno/Pro board. This gives to the user the capability to export easily a project originally made for the Arduino platform and transform it in a modular, tiny and powerful professional product.

The next figure shows a 3D view for the S100 Master - Duino Uno.

S100 Master - Duino Uno Top.png

           S100 Master - Duino Uno Bottom.png


  • Industrial automation
  • Robotics
  • DIY
  • IoT

Module Specification

The S100 Master - Duino Uno mounts the ATmega328P integrated circuit, a high performance, low power Atmel AVR 8-bit microcontroller. The Module provides 32 KB of in-system programmable flash with read-while-write capabilities, 1 KB of EEPROM and 2 KB of SRAM.

The S100 Master - Duino Uno mounts an USB to UART bridge to facilitate the connection to a computer and to easily program and debug the module. It is ready to use with the Arduino IDE. That is possible because a bootloader has been installed on the ATmega328P. Then, the user only has to plug the module on the Rhomb.io Master socket that will be found on the Rhomb.io Class 2 PCB and connect the USB to a computer.

The following figure identifies the main components onboard:

S100 Master - Duino Uno Description.png

The next figure shows the block diagram for the S100 Master - Duino Uno:

S100 Master - Duino Uno Block Diagram.png

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

S100 Master - Duino Uno Key Features
Microcontroller: Microchip ATmega328P, 8-bit AVR, 16 MHz
32 KB Flash, 1 KB EEPROM, 2 KB SRAM
Arduino IDE compatible; USB to UART converter
Encryption memory: 16 Keys/ECDSA/ECDH/SHA-256/SMAC/NIST
64-bit unique-ID memory with 112 B user EEPROM
MCU I/O: 23xI/O (6xPWM, 8xADC)
Rhomb.io config.: USB, UART, SPI, I2C, 2xINT, PWM, 11xGPIO, 2xAD
Op. voltage: 2.8 V / 3.3 V / 5 V
Op. temperature: -40 ºC to +85 ºC

User Interfaces

The following table indicates the available serial interfaces of the Rhomb.io standard used in this module. This table relates the interfaces of the Rhomb.io standard with the net names of the schematic and with the components to which they are connected.

Rhomb.io Interface Schematic Signal Component Component Pin Arduino IDE
I2C-A I2C-A_SCL ATmega328P (U1) PC5 (ADC5/SCL/PCINT13) A5
Crypto Memory (U4) SCL
I2C-A_SDA ATmega328P (U1) PC4 (ADC4/SDA/PCINT12) A4
Crypto Memory (U4) SDA
UART-A_TXD ATmega328P (U1) PD1 (TXD/PCINT17) 1
  • UART-A & USB: The UART-A interface can be translate to USB interface thanks to the USB to UART converter, so you can easily manage the S100 Master - Duino Uno by connecting it directly to your computer.

GPIOs and Control Signals

The following table summarizes the GPIOs and Control Signals used on the S100 Master - Duino Uno module. This table relates the signals of the Rhomb.io standard with the net names of the schematic and with the components to which they are connected.

Rhomb.io Signal Schematic Signal Component Component Pin Arduino IDE Comments
#NMI #NMI ATmega328P (U1) PD2 (INT0/PCINT18) 2 -
#RESET_IN #RESET_IN ATmega328P (U1) PC6 (#RESET/PCINT14) - -
USB to UART (U2) DTR# - "DTR" solder-jumper must me closed
1WIRE 1WIRE ATmega328P (U1) PC3 (ADC3/PCINT11) A3 "1WIRE" solder-jumper must be closed
ID Memory (U3) IO
AD AD0 ATmega328P (U1) ADC6 A6 -
CAPT CAPT0 ATmega328P (U1) ADC7 A7 Not real Capture interface
INT INT0 ATmega328P (U1) PD3 (PCINT19/OC2B/INT1) 3 -
IO IO0 ATmega328P (U1) PD4 (PCINT20/XCK/T0) 4 -
IO1 PD5 (PCINT21/OC0B/T1) 5
IO3 PD7 (PCINT23/AIN1) 7
PWM PWM0 ATmega328P (U1) PB1 (PCINT1/OC1A) 9 -
User LED - "LED" solder-jumper must me closed
RESET_OUT RESET_OUT ATmega328P (U1) PC3 (ADC3/PCINT11) A3 "RESET_OUT" solder-jumper must be closed
  • 1WIRE & RESET_OUT: Both signals are connected to the same microcontroller pin: PC3 (ADC3/PCINT11). Choose only one of them by opening and closing the "1WIRE" and "RESET_OUT" solder-jumpers. 1WIRE signal can be used to read the ID Memory; RESET_OUT signal reset the Rhomb.io Slave modules plugged on the same motherboard as the Master module.
  • CAPT0: This line is not a real Capture interface, it is the ADC7 microcontroller port taken outside through this pin.
  • PWM: PWM0 can control an on-board LED if the "LED" solder-jumper is closed.


The S100 Master - Duino Uno can use the 2.8 V rail, the 3.3 V rail or the VSYS rail. You can choose the voltage shorting the corresponding solder-jumper. Note that if you select VSYS rail, "1WIRE" solder-jumper must be closed too in order to protect all 1WIRE EEPROMS connected to 1WIRE bus, otherwise, they will be damaged. Make sure the rails are enabled on the motherboard you are going to plug this Module.

Analog voltage reference pin of the ATMega328P (AREF) is connected to "VIN_REG" signal of the Rhomb.io standard.

The power consumption varies with different power modes/sleep patterns and work statuses of functional modules. See the ATMega328P datasheet to find more information about power consumption.



Click the image below to download the schematic files.

Bill of Materials

Click the image below to download the BOM files.

Fabrication Data

Click the image below to download the fabrication files.

Mechanical Specifications

S100 Master - Duino Uno v1.1 (RL) Dimensions.png


  • 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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