Microchip Technology Inc

ATtiny3217 Product Family

Small AVR® Microcontrollers for Robust and Reliable Sensor Interface Applications


The ATtiny3217 family of microcontrollers incorporates several innovative features including high-accuracy analog, the Peripheral Touch Controller (PTC), the Event System and Core Independent Peripherals (CIPs) to allow you to create highly-responsive sensor nodes. This family offers up to 32 KB Flash memory in 8- to 24-pin packages to support a wide range of applications including industrial, consumer, appliances, automotive and Internet of Things (IoT) sensor nodes.


Responsive Signal Acquisition

Ideal for sensor nodes applications, the product family features a 10-bit Analog-to-Digital Converter (ADC) which provides accurate and timely analog signal acquisitions. Some family members have two 10-bit ADCs which allows advanced touch sensing and analog signal acquisitions to be performed simultaneously. For example, one ADC can be used with the Peripheral Touch Controller (PTC) for capacitive touch signal acquisitions, while the second one can monitor other inputs such as thermistors and pressure sensors. Another design option is to use both ADCs for faster sampling of different types of sensors.

Robust and Reliable Performance

There are many challenges when designing applications operating in harsh environments or control equipment with a high potential of damage to people or material. To address these challenges, these AVR® microcontrollers come with onboard safety and monitoring features to detect and respond to voltage level changes or drops. Additionally, the hardware Cyclic Redundancy Check (CRC) performs autonomous verification of the program memory to ensure that the application runs safely.


Getting Started


The ATtiny3217 Xplained Pro is the ideal platform for rapid prototyping with these new tinyAVR® MCUs. The USB-powered kit features an onboard programmer/debugger that seamlessly integrates with Atmel Studio, to offer an easy and convenient way to evaluate the device. The board also comes with touch buttons, LEDs and extension headers for quick setup.

For development with the smaller memory derivatives of the tinyAVR family, we also recommend the ATtiny817 Xplained Pro Kit.

Significantly reduce your development time with Atmel START, our intuitive, web-based graphical configuration tool for embedded Projects. Atmel START generates factory-validated C-code to help get your design started quickly. Get started today at microchip.com/start With a few clicks, START projects can be imported into the Atmel Studio Integrated Development Environment (IDE) and can be easily modified at any time later, e.g. to add or remove START code. Download Atmel Studio 7.


Building Blocks for Sensor Nodes and Real Time Control

Peripheral Touch Controller (PTC)

The Peripheral Touch Controller (PTC) offers built-in hardware for capacitive touch sensors that function as buttons, sliders and wheels for the product user interface. The PTC is designed to perform capacitive touch acquisition on sensors independently from the Central Processing Unit (CPU), resulting in minimal CPU load and a reduced power consumption. The PTC is a robust, proven technology that combines low response time, water resistance even in harsh and challenging environments. 

Integrated Analog
The onboard 10-bit, 115 ksps Analog-to-Digital Converter (ADC) features selectable internal voltage references with minimal temperature drift. Improve noise suppression and accuracy for analog inputs with the hardware averaging and oversampling, resulting in up to 13-bit resolution. Averaging and threshold detection allows the MCU to remain in sleep mode for longer periods, significantly reducing power consumption.
The onboard analog comparator can be connected to other peripherals through the event system to trigger autonomous operation in those peripherals, such as PWM shut-down, which is ideal for real time control and closed-loop operations.
Event System

The Event System allows peripherals to communicate directly with each other without involving the Central Processing Unit (CPU) or bus resources. The Event System network is independent of the traditional data bus paths. This means that a condition in a peripheral can result in an event, such as a timer’s overflow triggering an action in another peripheral. The Event System has six independent event channels for direct peripheral-to-peripheral signaling. Events provide a deterministic signaling method and a is a perfect fit for real-time applications. They are handled without latency at the peripheral level regardless of the CPU is busy executing tasks, handling interrupts, or even when the CPU is in sleep mode.

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Configurable Custom Logic

The Configurable Custom Logic (CCL) is a programmable logic peripheral which can be connected to the device pins, events or other internal peripherals. Each Lookup Table (LUT) consists of three inputs: a truth table, an optional synchronizer and a filter and edge detector. A LUT can generate an output to be routed internally or to an IO pin. This eliminates the need for external logic and reduces BOM cost.

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Onboard Safety and Monitoring
Add robustness and reliability to an application by utilizing the built-in features, such as the Windowed Watchdog Timer (WDT), the Cyclic Redundancy Check (CRC) feature to scan the Flash memory and fault detection using the Event System, to support safety critical applications. Take advantage of supply voltage monitoring capabilities with safety features like the Power-On Reset (POR), the Brown-Out Detector (BOD) and the Voltage Level Monitor (VLM). All these features are integrated into each of the ATtiny3217 family members, enabling the design of safer and more robust applications.
Cyclic Redundancy Check (CRC)

The Cyclic Redundancy Check (CRC) is used to verify the program memory contents. The CRC scan calculates the checksum of the entire Flash memory, or parts of it, and automatically compares it with the expected result. In this way it can detect errors in program memory quickly. The CRC can scan at run time, or it can run during reset to ensure that the flash is valid before the CPU is allowed to execute the code. When the CRC scan is done at run time it periodically halts the CPU to quickly complete the scan.

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Windowed Watchdog Timer (WWDT)

The Windowed Watchdog Timer (WWDT) is a system supervisory circuit that generates a reset if software anomalies, like runaway or deadlocked code, are detected. When enabled, the WWDT is a constantly running timer configured to a predefined timeout period. If the WDT is not reset within the timeout period, it will issue a System Reset.

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Power-On Reset (POR)

Safe startup of a  microcontroller is depending on a sufficient supply voltage level. During power-up of a device it is important to give the device a reset to put everything in a known state. It is equally important that both memories and digital logic have a sufficient supply voltage to operate correctly. When the supply voltage rises, the POR is activated and will hold the device in reset until the voltage is above a fixed threshold value. The POR continues to monitor the supply as long as the device is powered and will activate reset if the supply voltage drops.

Brown-Out Detector (BOD)

The Brown-Out Detector (BOD) feature monitors the power supply and compares the voltage against a programmable threshold. The BOD ensures that the device is operating within specification to prevent erroneous code execution and memory writes. If the voltage drops below the set threshold, the BOD issues a system reset and will hold the device in reset until the voltage has risen above the set threshold again.

Voltage Level Monitoring (VLM)

The Voltage Level Monitor (VLM) monitors the power supply and can be configured to generate an interrupt if the supply voltage passes below a given threshold. This can act as an "early warning" to the application that the supply voltage is passing the VLM threshold and the application can take the necessary actions to safely prepare for a possible brown-out situation (power loss). A safe shutdown can benefit from the fast EERPOM page-write of the tinyAVR microcontrollers to store critical system parameters. The threshold is configured by the user and is expressed in percentage above the configured BOD level.

ATtiny3217 Key Attributes

  • Internal 20 MHz oscillator
  • Up to 32 KB of FLASH memory
  • Up to two 10-bit ADCs
  • Peripheral Touch Controller (PTC)
  • 8-bit DAC
  • Cyclic Redundancy Check (CRC) scan
  • 16-bit real time clock and periodic interrupt timer
  • Advanced 12-bit timer/counter for control applications
  • Configurable Custom Logic (CCL) peripheral
  • 6-channel Peripheral Event System
  • Analog comparator reference input
  • Configurable, internally generated reference voltage