Review: ATtiny817 Xplained Mini

February 2, 2017 | 11:40
Review: ATtiny817 Xplained Mini
Review: ATtiny817 Xplained Mini
Of course I know that Atmel is now Microchip, yet I was a bit surprised to find on my desk an Atmel ATtiny817 Xplained Mini board together with a Microchip USB stick. And what to think of this line at the end of the accompanying press release? “For more information, visit Microchip’s Web site at www.atmel.com/tinyAVR”. Multiple personality disorder?

Let’s have a look at the board and the micro on it.

The square ATtiny817 Xplained Mini board measures 60 x 60 mm (2.36 x 2.36”) and has a micro USB connector sticking out on one side, giving the board a strange shape. This appendix is the size of a PCB USB A-type plug that could have been plugged directly in a USB slot, but since it has a micro USB connector mounted instead of board edge contacts this is not possible. I am sure the designer had good reasons for doing things this way.

There are many holes on the board. Holes with square pads are Arduino shield compatible. Some of the other holes have white rectangles drawn around them. The board has a user LED, a pushbutton and two QTouch tactile pads. It also has a mini embedded debugger (mEDBG) that allows you to program and debug the board from Atmel Studio 7 (AS7), but it is also a virtual COM port (make sure the DTR signal is activated by the terminal program for this port to work). Many configuration options are available if you have access to a soldering iron.

Core Independent Peripherals

In the center of the board sits the ATtiny817. It is a member of a new generation of 8-bit tinyAVR MCUs that feature Core Independent Peripherals (CIPs). Inside the chip we encounter the split personality once more: the core is Atmel AVR, the core independent peripherals are Microchip PIC. At the time of writing there are four devices in this family: ATtiny817, ATtiny816, ATtiny814 and ATtiny417. The Microchip website also mentions an ATtiny416, but the Atmel site doesn’t know about it. The datasheet shows the ATtiny1616 and ATtiny1617, these are probably upcoming devices.

The tiny8xx have 8 KB of flash memory, the tiny4xx devices have 4 KB (the 16xx parts will have 16 KB). The second digit, the ‘1’, indicates the feature set, so we can expect more siblings in this family. The last digit indicates the number of pins: ‘7’ means 24 pins, ‘6’ stands for 20 pins and ‘4’ for 14. What would ‘5’ be?

The devices come with the standard peripherals like timers, USART, SPI, TWI (I²C), ADC, etc., but there are also some less common peripherals like an 8-bit DAC, Configurable Custom Logic (CCL) offering glue logic, two programmable LookUp Tables (LUTs) programmable logic and other functions, a CRC checker (CRC-16 CCITT), a Port Multiplexer that allows relocating of some pins, and an Event System (ES). The ES is what makes core independent peripherals (CIPs) possible. It allows a change in one peripheral (the Event Generator) to trigger actions in other peripherals (the Event Users) through Event channels, without using the CPU.
 
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