Designed for work in circuits with varied voltage levels.

 

Until recently, a very common problem faced by electronic circuit designers was the difference in supply voltage standards between microcontrollers (e.g. 3.3 V) and peripheral ICs (e.g. 5 V). In order for them to operate together, the use of additional voltage translators was required, which made the device more complicated and increased the final price. Now, this is a thing of the past.

Microchip, a company that is known for its broad portfolio of 8-bit microcontrollers from the PIC® and AVR® families, continues to expand its assortmentrange. The newly developed ICs combine the best features of both product groups, offering to electronic designers a wide range of possibilities and making it easier to develop circuits that are even more integrated. This is the case with the energy-efficient, 8-bit microcontrollers from the AVR®DD/DB families. They feature a unique set of peripherals that operate independently from the core (CIP, Core Independent Peripherals), primarily for efficient analogue signal processing. They also ensure safe operation of applications in compliance with the IEC61508 and ISO26262 standards. Thanks to them, the AVR®DD/DB microcontrollers are perfectly suited for the needs of simple applications. They can also serve as companion (support) chips in more complex projects.

In this article, we discuss topics such as:

The design of AVR® DB and DD microcontrollers
The advantages and applications of the MVIO integrated voltage translator
Prototyping and learning with the Curiosity Nano kits
Clock signal supervisor IC
The EVSYS and direct communication between the peripherals
The advantages and capabilities of the built-in Custom Logic circuit
Operational amplifiers in AVR®DB microcontrollers
The operation of a core-independent ADC converter
General information about the AVR® DB and AVR® DD microcontrollers

The microcontrollers presented here have been designed to speed up and facilitate the design phase, thanks to which the production of the target device can be implemented quickly. Microchip accomplished this goal by integrating the AVR core with a range of peripherals in a single structure, allowing it to perform many tasks that previously had to be handled by external circuits. What’s more, the DB and DD products are available in a range of formats, from the classic DIPs  to VQFN packages with a footprint of only 5×5 mm. This satisfies the needs of modern electronic circuits, such as remote IoT devices or programmable controllers, relays and industrial sensors.

 

To begin with, it should be noted that the ICs presented here have all typical features and functions of the Microchip products. They are clocked at 24 MHz, offer up to 128 kB of Flash memory (software memory), 16 kB of SRAM (operational memory) and 512 B of non–volatile EEPROM, traditionally used to store data on setpoints, serial numbers etc. The enclosures of the microcontrollers are fitted with up to 64 pins with diverse functionalities. Apart from the traditional role of the I/O ports (i.e. GPIO), they have been combined with ADCs  and SPI, I2C, UART serial interfaces. A real-time clock (RTC), counters/timers (used, among other things, for generating PWM signals), analogue comparator and reference voltage sources (with several values) have also been integrated with the microcontrollers. In addition, the chip includes a digital-to-analogue converter (DAC) and an advanced watchdog. Other, more advanced components operating independently from the core (CIPs) have been discussed in detail later in the text.