In the context of controls that move cranes, Road Implements and multi-ton loads, a wrong command is not just a defect: it is a potential accident. At the center of all this is the microcontroller, the component that interprets each button pressed and decides what the equipment should do.

The security of a system like this does not depend on a single resource. It is built in layers, ranging from the hardware of the chip itself to the way memory is managed and the firmware logic. In this article, we show each of these layers and how they are applied to Tecnnic products.

Why the microcontroller is the centerpiece of security

The microcontroller reads the operator's commands, manages radio communication and activates the outputs that move the equipment. If it crashes, restarts unexpectedly, or reads a corrupted value, an output could be triggered unintentionally.

Therefore, the entire project is based on a simple principle: when in doubt, the system switches off. It is the concept of fail-safe, in which any uncertain condition brings the equipment to a safe state. The challenge is to ensure that the system perceives these situations and reacts appropriately. That's where layers of protection come in.

First layer: hardware protections on the chip itself

Modern microcontrollers have internal supervision circuits, all activated and audited in the Tecnnic firmware. Undervoltage detection keeps the chip in reset during starts or power instabilities, preventing the execution of incorrect instructions. If the program crashes, the safety timer resets the microcontroller to prevent outputs from remaining activated inadvertently. Complementing this protection, the clock monitor detects main oscillator failure and switches the chip to an internal backup clock source, while memory overflow protection prevents runaway executions.

This allows the microcontroller to restart safely whenever necessary. But when it comes back, it needs to find its settings intact.

Second layer: reliable memory

Equipment configuration needs to withstand years of use and power outages that can happen at any time. To achieve this, Tecnnic uses triple redundancy: each important data is recorded in three different positions and, when read, the copies are compared, with the majority value prevailing. This way, a single corrupted bit does not turn into an erroneous operating parameter, a technique with roots in the aeronautics and space industry. The recording is also alternated between different areas of the memory, distributing wear and multiplying its useful life. Additionally, if the power goes out in the middle of a recording, the firmware identifies the situation at the next start and recovers the last healthy version of the data.

With the hardware protected and the memory reliable, the most important part remains: what the program does with it all.

Third layer: firmware

If the hardware protects against failures of the chip itself, the firmware protects against failures of the system as a whole: communication, sensors, operation and load. At Tecnnic, the firmware is developed internally, with security treated as a requirement from the first line of code.

When the radio signal is lost, the receiver quickly turns off the outputs, while the transmitter seeks to reestablish the connection without sending any commands. A sensor that loses communication during operation also returns the system to a safe state. Commands are only accepted with the dead-man device activated, and any command active when the control is turned on is blocked, preventing activations caused by a stuck lever or an object resting on the control. The receiver also monitors power outputs and blocks them in the event of abnormal consumption or power out of range. Finally, each radio message carries identification and integrity checking, and any unknown or corrupted messages are simply discarded.

Firmware that takes care of the battery

In portable equipment, the battery is also a safety issue: a control that turns off unexpectedly interrupts operation in the middle of a job. Energy management is one of Tecnnic’s strengths. The microcontroller, radio and peripherals remain active only when necessary, without any noticeable delay in responding to the operator. When the load is low, the operator is warned in advance, momentary drops in voltage do not turn off the control and, at the end of the load, the shutdown takes place in an orderly manner.

The result is a Tecnnic radio capable of working about 100 hours per charge on a single Li-ion 18650 battery, under typical operating conditions.

Security as a result of layers

None of these layers alone would be sufficient. The hardware guarantees safe operation, the memory preserves the correct settings and the firmware takes the system to a safe state in the event of any doubt, also taking care of the battery. Together, they result in equipment that operates with confidence on a daily basis and that, when something goes out of the ordinary, stops in the right way.

By Elias Enns,
Full Developer at Tecnnic Eletrônica Industrial

Microcontroller Security Frequently Asked Questions (FAQ)

What is undervoltage detection (brownout) and why is it important?

It is the feature that monitors the microcontroller's supply voltage. If power drops below the operating threshold, the circuit keeps the chip in reset to prevent it from executing corrupted instructions during startup or in the event of instability.

How does the security timer (watchdog) work?

It is an internal supervision circuit that automatically restarts the microcontroller if the program becomes unresponsive or crashes, preventing outputs from remaining activated inadvertently.

Why do Tecnnic receivers quickly turn off outputs when they lose radio signal?

This is the concept of fail-safe: in the absence of a confirmed and complete instruction, the system adopts a safe state and stops any movement to avoid accidents.

How does the firmware ensure that settings are not corrupted by power outages?

Tecnnic uses triple redundancy when recording critical data in memory, and recovery routines that restore the last valid version if recording is interrupted abruptly.

How long does the battery of a Tecnnic portable radio last?

Around 100 hours per charge, under typical operating conditions, using a single Li-ion 18650 cell, thanks to aggressive management of low power states in the microcontroller and peripherals.

Could saving energy to preserve the battery delay commands or compromise safety?

No. Power management operates without affecting operator response time or firmware security routines.