Assembled board shown for reference only - this is the listing for the BARE BOARD

Assembled boards with ATtiny412 or ATtiny402 are available my other listing

This is a breakout board for the new ATtiny megaAVR x2 series - supports 412, 212, 402, 202 - all the 8-pin megaAVR 1-series and 0-series ATtiny parts. These are highly capable and affordable ATtiny parts - prices are lower than most classic AVR ATtinys with the powerful megaAVR peripherals. These parts are fully compatible with Arduino using my megaTinyCore, too.

Board Features

• 1 LED connected to PA7 (Arduino pin 3)
• 1117-series or compatible voltage regulator
• 4.7k resistor for UPDI programming
• 3-pin header for UPDI programming
• 6-pin header for Serial (FTDI pinout)
• 2 pin Vin header for external power (input to regulator)
• 4 Gnd and Vcc pins - easily power multiple devices from the breakout board without having to make Y-cables!
• All pins broken out to headers at 0.1 pitch

ATtiny Features

• 5 usable I/O pins
• 1.8v~5.5v operation
• up to 4kb of flash
• up to 256b of SRAM (on 1614)
• DAC (1-series parts only)
• 1 PWM pin exposed via Arduino core

BOM

U1 ATtiny 412, 212, 402, 202

C1 1206 0.1uF Cap - decoupling

C2 1206 Output Cap for regulator and power supply filtering (4.7uF or as directed by regulator datasheet)

C3 (If using regulator) 1206 Input Cap for regulator (4.7uF or as directed by regulator datasheet)

C4 Do Not Use

R1 1206 4.7k resistor

R2 Do Not Use

R3 1206 resistor (ballast for LED - 2.2k ~ 220 ohm depending on how bright you like your LEDs)

D1 Do Not Use

LED1 (optional) 1206 LED, this is connected to PA7 (Arduino pin 3) -

F1 (if using regulator) 1206 PTC fuse (1A max recommended, can replace with jumper if you like to live dangerously or your power supply is already current limited)

U2 (optional) 1117-series or compatible voltage regulator in SOT-223 package (Recommended: LDL1117)

Pin Header - 1x3 for UPDI header, 1x6 for FTDI serial header. 2 1x15 headers for the I/O pins - recommend normal square header for use with DuPont jumpers, or machined pin header for use with breadboard. All 0.1" pitch.

Power header (if using regulator) Your preferred 2-pin power connector (or wires to in-line connector), 0.1" pitch.

Note: Reference designators are missing from the top silkscreen in this version of the board. Refer to images as reference; part locations are:

U1, U2 - obvious

2 1206 parts on either side of UPDI header - R3, LED1

2 1206 parts between UPDI header and U1 - (starting from UPDI header) R1, C1

2 1206 parts between regulator and Vin header (starting from edge of board) - F1, C2

1 1206 part on other side of regulator - C3

3 parts in corner near FTDI header - C4, R2, D1 - Do not use (this is for an autoreset circuit - this is only useful with serial bootloader and UPDI disabled (as it will prevent UPDI programming), such a bootloader will be introduced in a future version of megaTinyCore, but is not currently available)

Programming the megaAVR ATtiny parts

Unlike other AVR microcontrollers, these new parts are programmed via a "UPDI" singlewire interface instead of the SPI-based ICSP protocol. You can easily use a standard Arduino Nano, Uno, or Pro Mini as a UPDI programmer, this is what we use and recommend - see the instructions here:

Make UPDI programmer from Nano/ProMini/Uno

The order of the pins on the UPDI header is UPDI-Gnd-Vcc - this means that if the programmer is connected backwards, the board will not be damaged. The 4.7k resistor is on the breakout board; you do not need to (and should not) use another one.