This is a simple development board for the Atmel ATtiny841 or ATtiny84 (or the 2k or 4k versions of those). It provides the familiar 6-pin FTDI header for connecting to serial and ISP header for programming via ISP, and it has the capacitor for auto reset. A jumper is provided to enable or disable auto reset. Pads are also provided for external power in, capacitors, and a SOT-223 voltage regulator (if desired), and a crystal, (also if desired). The pads for the filter across the power supply are sized to accommodate anything from an 0805 ceramic to a tantalum capacitor, as shown in the pictures. These boards now feature ENIG surface treatment, and V-groove panelization.

Using the core available from my Github at https://github.com/SpenceKonde/ATTinyCore the ATtiny841/441 or 84/44/24 can be used with the Arduino IDE, with optiboot bootloader support for the Tiny841.

This board is sold UNPOPULATED - SOIC-14 is a great package to practice drag soldering with :-)

Available Assembled - click here

What makes it special?

What sets this apart from a typical ATtiny84 breakout board is that it provides the appropriate header for serial programming of an ATtiny841. Because the '84 did not have a hardware UART, very few people bothered to use it with a bootloader, and so there was no reason to provide a serial programming header. Now, with optiboot and a working Arduino core, programming the Tiny841 is as simple as programming a Pro Mini.

The ATtiny841 - a remarkable step up from the 84

• 12 ADC channels (one on every IO pin, including reset)
• 2 Hardware UARTs
• 3 independent timers, 2 of which are 16 bit, each with two PWM channels (ie, SIX PWM CHANNELS).
• Hardware SPI

Parts required (not included):

All of these parts (except the microcontroller itself) are common parts. Most SMD passives are 1206 to facilitate hand soldering. Reference designators shown in italics.

• ATtiny84, 841, 44, 441, 24, or 241 MCU
• 1 0.1uf 1206 ceramic capacitor (2 if using DTR reset) C1, C5
• 1 piece 2x3 0.1" pin header (for ISP programming)
• 2 piece 1x8 0.1" pin header
• 1 piece 1x6 0.1" pin header, recommend 90 deg angled (for FTDI header)
• 1 piece 1x2 0.1" pin header (if using DTR reset - this is now optional, as Rev. C comes with this connection closed by default)
• 1 10k ohm 1206 resistor R1
• 1 1206 LED (if desired - recommended) LED1
• 1 1206 resistor for aforementioned LED, 220 ohms minimum, recommend 1-2k R2
• 1 small diode (SOD-123, DO-80, etc), if using DTR reset D1
• 1 capacitor (0805, 1206, or small-medium tant; consult regulator datasheet if using one) for power supply filtering (optional, highly recommended) C4
• 1 1206 ceramic capacitor for external power supply filtering (if using regulator - per regulator datasheet) C7
• 1 voltage regulator in SOT-223 package, like a ZLDO1117 (optional - note that some regulators do not behave well if the input is not powered) VREG
• 1 HC/49 SMT crystal Q1, and 0805 loading caps per mfg. spec (optional) C2, C3
• 1 external power connector on 0.1" centers (optional)