NORVI Cema (Cema automator)

Today we will analyze (in the literal and figurative sense of the word) another Norvi controller, this time not on the ESP32 familiar to us from previous articles, but on the “good old” ATmega32U4 microcontroller. This chip is used in the popular Arduino Micro board (as well as in the Arduino Leonardo) and you may have come across it before in your projects.

NORVI Cema is a modified version of the Arduino Micro, adapted for use in automation, made in a package typical of the Norvi controller line. So typical that you can’t immediately tell which controller we are dealing with and what is inside it.

It will be even more interesting how the inner world of NORVI Cema differs from the previously reviewed controllers on ESP32…

NORVI Cema family

Controllers of the NORVI Cema family are an example of minimalism in everything: a fairly simple microcontroller as a core, an ascetic set of functions, no frills, only digital inputs and relay or transistor outputs. Since the ATmega32U4 microcontroller is used as the core, we are not talking about communication capabilities either, NORVI Cema is a completely autonomous controller.

This immediately determines the scope of these controllers – simple automation circuits, where you need to receive data on the state of digital inputs and, according to some algorithm, control relay and transistor outputs.

The presence in the controllers of the NORVI Cema line of a display and control buttons on the front panel of the case somewhat enlivens the picture, so that you can control the controller “beautifully” and with convenience – interactively change settings and operating modes and display the necessary information on the display.

The NORVI Cema family of controllers has (at the moment) only two models – either with only transistor outputs, or combining relay and transistor outputs.

Model 1, which I have, is highlighted in gray.

Obviously, the choice of a particular model should be determined by your task – what and how you need to control and what is better to do in your particular case – transistors or relays.

Components and Specifications

Now, from a general description of the NORVI Cema line, we turn to the consideration of the NORVI Cema Model 1 model, which is at my disposal.

NORVI Cema Model 1 Components and Specifications:

This model is deprived of the attribute of Norvi controllers that has already become familiar to us – the interconnect. In the minimalist spirit of the NORVI Cema line, there is no possibility to connect additional units and expand the basic functionality of the controller. This is how a simple automator Syoma is seen in a working overalls and with a wrench in his hand – there are not enough stars from heaven, but he tightens the nuts (controls the exits) quickly and reliably.

Internal organization

The internal structure of the NORVI Cema line controllers is made according to the same scheme as in the previously considered NORVI IIOT and NORVI ENET controllers. These are two boards connected together using two racks with pins. It is possible to understand which controller we are dealing with only by turning the assembly of boards in our hands and finding the control microcontroller on them.

There are good, I would even say great news: since NORVI Cema does not have an interconnect, then (finally!) This controller can be normally, easily and simply disassembled – nothing interferes with the assembly / disassembly process – no need to bend the boards, apply strength and be afraid that something will crack and fall apart right in your hands.

View from the right side: there is no interconnect and a hole for pressing the “Reset” button is visible.


The internals of the Norvi controllers are so similar that you can play a game of “find 10 differences”. Here, the presence of a relay on the board and the absence of a USB-UART adapter chip immediately catches the eye (NORVI Cema does not need it, since it uses the ATmega32U4 microcontroller). Other differences are less noticeable, such as a smaller number of pins in the board-to-board connections and the presence of two additional LEDs to indicate RX / TX interaction when transmitting data over the UART interface.

Now it becomes clear that there are “rudimentary” inscriptions “TX / RX” for the LEDs on the front panel of the Norvi controllers. Apparently, for reasons of economy, one universal case was made for all models, which is why we see extra designations where the necessary parts are missing in different models.

Again, an important reminder. The official documentation of NORVI Cema controllers still remains a collection of all possible errors and blunders – everything that can be confused is mixed up. Therefore, it is recommended that before connecting something according to the Iconic Devices manuals, double-check everything ten times (and use the articles in this cycle – everything that is written here is true and verified by me).

Pin assignment and indicator location NORVI Cema Model 1

Interface between boards

The controller boards are interconnected by two groups of contacts P1 and P2. Here, unlike the previously reviewed controllers on the ESP32, each group contains not 12, but 10 contacts, the contacts themselves are made one-piece – everything is soldered to death. I would rate the soldering itself somewhere between 3+ and 4-, it would be possible to solder the contacts even better.

The bottom board contains blocks for connecting the inputs, outputs and power supply of the controller (24 V), elements of the power subsystem, 6 relays and other components.

The top board contains an ATmega32U4 microcontroller, a Mini-USB connector, a display, control buttons, indicator LEDs, a configuration jumper block, and other elements.


The power subsystem consists of a switching step-down voltage regulator on the LM2596S (5 V) and its piping elements. The input voltage specified by the manufacturer must be 24 V (in reality, the controller also operates from a lower voltage).

View of the elements of the NORVI Cema power subsystem: an LM2596S DC-DC converter chip, inductance, diode, filter capacitors and other elements.

The normal mode is the power supply of the controller through the contacts of the terminal blocks, but it can also be partially powered from the Mini-USB connector, in this case the ATmega32U4, display, outputs will work and it will be possible to upload firmware to the controller.

ATmega32U4 core

NORVI Cema uses the popular ATmega32U4 microcontroller (Arduino Micro, Arduino Leonardo) as the core, which is located on the back of the top board.

USB connection

For connecting to a computer, programming and uploading firmware to NORVI Cema, there is a Mini-USB connector on the top board. There is no separate USB-UART converter chip, since the ATmega32U4 microcontroller already contains this subsystem.

The photo (on the side and partially) shows the “Reset” button, which is located on the right side of the top board. On the case there is a corresponding hole for pressing it.

Digital inputs

NORVI Cema Model 1 has 8 digital inputs connected via two TLP290-4 chips, each containing 4 optocouplers.

Below is the NORVI Cema digital input connection diagram. There are two options with a “plus” on the COM contact and with a “minus”, in the terminology of the manufacturer “Sink” and “Source”.

Correct numbering of GPIO inputs:


Relay and transistor outputs

NORVI Cema Model 1 has 6 relay and 2 transistor outputs. The maximum current of the relay outputs is 5A, and the maximum current of the transistor outputs is 500 mA.

The internal scheme of the operation of relay and transistor outputs of NORVI Cema controllers: in the case of a relay, the voltage connected to the COM contact is switched to the outputs, and in the case of transistors, the outputs are connected to the “ground”.

Correct numbering of GPIO outputs:



NORVI Cema uses an OLED display SSD1306 – it is convenient to display all the necessary information on it.

With software support for the SSD1306 display, everything is fine – you can find a huge amount of code for it on the Internet. The display address on the I2C bus is 0x3C.


Working with buttons in NORVI Cema is organized differently than in the previously reviewed ESP32 controllers. Here, each button is connected to a separate GPIO pin, which makes it somewhat faster and easier to process their pressing.

Correct numbering of GPIO buttons:


LED indicators

In NORVI Cema (unlike other controllers) we have a complete set of indicator LEDs. There are LEDs for inputs, outputs, controller power, and TX / RX data transfer activity.


And in conclusion, I will give the pinout of the NORVI Cema Model 1 controller restored by me bit by bit. The purpose of the D17 output remains unclear, perhaps it is simply not connected anywhere in this model.


We reviewed the design and purpose of the NORVI IIOT, NORVI ENET and NORVI Cema controllers and have already become experts in Norvi products, in the next article we will continue our acquaintance with these controllers and analyze in detail NORVI Agent 1 (AT01-BM1), which is available in a compact package (width 36 mm) and has an ESP32 module on board.

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