The Atmel ATtiny series of low cost AVR microcontrollers is a very attractive option for Arduino users looking for a smaller, less expensive processor for "shrinkifying" their Arduino projects. While the ATtiny x4 and x5 series have a long history of use with Arduino, there are other ATtiny processors, many with unique feature sets. In some cases these exceed the features available on the ever popular ATmega328 processor. Unfortunately, many of the most exciting new parts are only available in surface mount packages - this tyically means using general purpose breakout boards. Because they aren’t designed for the specific chip you’re working with, there are no provisions for locating supporting components close to the chip. In the case of parts like crystals and decoupling capacitors, this can impact functionality.
These ATtiny breakout boards are designed for a specific Atmel chip (or in some cases a small number of parts with similar pinouts), and provide appropriate pads for decoupling capacitors, crystals, and other essential components. All LEDs and passives are in 1206 package for ease of assembly, except for crystal loading caps, which are 0805 (this seems to be more common for those, for some reason). Crystal footprint accomodates both SMD and through-hole HC/49 crystals. The supply filtering capacitor can be anything from 0805 ceramic to a 6032 tantalum capacitor, to accommodate picky regulators or demanding filtering requirements.
Connectivity
All pins are broken out to 0.1” header, with the Arduino pin mappings for each pin marked in silkscreen. Pins may be installed facing up for use with jumper wires - or down, for use with breadboards. Multiple Vcc and Gnd pins (4-6) are provided, so you don’t need a "splitter" get enough Vcc and Ground connection points if you're not using breadboard.
Programming headers are provided for ICSP programming on all boards, with the standard 6-pin 2x3 pin header (reset pin is marked). For boards supporting chips that include a hardware serial port, a 6-pin FTDI-style header is provided for serial programming with a bootloader (on serial port 0); the DTR pin is connected to a capacitor for the DTR-reset mechanism, and can be enabled with the RST_EN jumper (a feature that official Arduino boards lack). On boards with the FTDI header, pads also provided for a signal diode from RST to Vcc to prevent it from rising above Vcc. Some boards support mulitple series' of chips with different pinouts for serial or ICSP programming; on these boards, two headers are provided, with the part they are to be used with marked on silkscreen
Power options
Power can be provided directly to Vcc/Gnd (through those headers, or through FTDI or ISP header). Additionally, a regulator for external power supply at a higher voltage can be installed on the included SOT-223 pads. Power for the regulator comes in through a 2-pin header (on 0.1” centers - suitable for dupont or KK-100 connectors), and pads are provided for a 1206 PTC "polyfuse" for short circuit protection (these can be jumpered with a 0 ohm resistor (or wire) if your supply is short circuit protected or you like to live dangerously)
Assembled Boards
Some of these boards are available assembled. These are pre-loaded with Optiboot (if available) and configured to use the external clock source (if included). These boards use a 4.7 uf or 10uf 0805 ceramic capacitor for power supply filtering, 1A polyfuse (where supported), and 1117-series voltage regulators. LED series-resistors are sized to limit LED current to a couple of milliamperes (allowing the pin to be used for most other tasks without removing the LED), meaning 800-1.2k ohm for 5v boards and around 500 ohm for 3.3v boards. LED colors will vary. For processors available in R version (with improved internal oscillator calibration) are used for all boards that do not include a crystal.
Supported processors:
- AZB-4: ATtiny 841,441,84,44,24
- AZB-7: ATtiny 167,87,861,461,261
- AZB-8: ATtiny 828,88,48, ATmega328,168,88,48,168PB,88PB,48PB
- AZB-34: ATtiny 1634
All ATtiny-series processors listed are supported by one of my ATtiny cores. Microcontrollers with 8k or more of flash with a hardware UART have Optiboot bootloader support as well
ATtiny x41/x4 breakout board - AZB-4
$1.75 PCB, $12.00 Assembled
Bare Board
Assembled
This is a simple development board for the Atmel ATtiny841 and 441 parts, available both assembled and as a bare board. This board will also accomodate ATtiny 84, 44, and 24 processors - but these do not have hardware serial support. The Atmel ATtiny841 microcontroller is an incredibly capable processor in a tiny package, costing pennies more than the 84, while providing vastly greater capability. The ADC is one of the most full featured in the 8-bit AVR line. The second UART makes this chip particularly well suited for use with serial peripherals (like GPS's or the ESP8266 wifi module), as the second UART can be used without interfering with programming or debugging over serial.
These support the Optiboot bootloader, so they can be programmed over serial like a normal Arduino.
ATtiny 841 Features
- 8k Flash, 512b EEPROM, 512b SRAM
- Dual hardware UARTs
- Hardware SPI master/slave
- Hardware I2C slave
- Six PWM outputs
- 1 8-bit and 2 16-bit timers
- 11 GPIO pins
- Advanced ADC
- 12 analog inputs
- 46 differential input pairs
- Programmable gain: 1x, 20x or 100x
- on-chip analog comparator
- 8mhz (internal), up to 16mhz (external crystal)
Required Components
Parts not included on assembled units marked in bold.- ATtiny 841
- 2x 0.1uf 1206 capacitors (1 if not using auto-reset)
- 10k 1206 resistor
- 1206 LED + appropriate resistor
- 0805-6032 capacitor for supply filter
- HC/49 Crystal (optional, up to 12mhz)
- 2x 0805 18pf ceramic capacitor (optional, for xtal)
- SOT-223 voltage regulator, like 1117-series (optional)
- 1x 1206 ceramic capacitor (optional, regulator input)
- 0.1" pin header, 1x6 pins (FTDI header)
- 0.1" pin header, 2x3 pins (ICSP header)
- 2x 0.1" pin header, 1x10 pins
- 0.1" pin header, 1x2 pins (RST_EN)
- 0.1" pin header or KK-100 connector, 1x2 pins (ext. power)
Revision History
- Rev. B: Improved silkscreen, cleaned up routing.
- Rev. A: Switched to SOT-223 regulator, blue soldermask. Many improvements to layout and design.
- Rev. -: Used green solder mask, SOT-23-5 regulator, no bottom silk, no ground plane.
ATtiny 1634 breakout board - AZB-34
$2.00 PCB, $14.00 Assembled
Bare Board
Assembled
This is a simple development board for the Atmel ATtiny1634, available both assembled and as a bare board. The Atmel ATtiny1634 microcontroller is a very capable and economical processor. It's relatively large flash and SRAM (for a tiny), and 17 GPIO pins allow it to fill a space between the smaller Tiny's, and the low end of the ATmega line. The second UART makes this chip particularly well suited for use with GPS, GSM, and serial WiFi adapters (like the ESP8266), as they can be used without interfering with serial programming or communication - without resorting to software serial.
These support the Optiboot bootloader, so they can be programmed over serial like a normal Arduino.
ATtiny 1634Features
- 16k Flash, 256b EEPROM, 1k SRAM
- Dual hardware UARTs
- Hardware USI (for SPI or I2C master or slave)
- Hardware I2C slave
- Four PWM outputs
- 12 analog inputs
- 17 GPIO pins
- Optional external AREF
- on-chip analog comparator
- 8mhz (internal), up to 12mhz (external crystal)
Schematic
Required Components
Parts not included on assembled units marked in bold.- ATtiny 1634R or 1634 (not recommended w/out crystal)
- 2x 0.1uf 1206 capacitors (1 if not using auto-reset)
- 10k 1206 resistor
- 1206 LED + appropriate resistor
- 0805-6032 capacitor for supply filter
- HC/49 Crystal (optional, up to 12mhz)
- 2x 0805 18pf ceramic capacitor (optional, for xtal)
- SOT-223 voltage regulator, like 1117-series (optional)
- 1x 1206 ceramic capacitor (optional, regulator input)
- 1x 1206 PTC Polyfuse (optional, regulator input)
- 0.1" pin header, 1x6 pins (FTDI header)
- 0.1" pin header, 2x3 pins (ICSP header)
- 2x 0.1" pin header, 1x13 pins
- 0.1" pin header, 1x2 pins (RST_EN)
- 0.1" pin header or KK-100 connector, 1x2 pins (ext. power)
Revision History
- Rev. A: Added PTC fuse, changed to yellow solder mask
ATtiny x61 and x7 breakout board - AZB-7
$2.25
This is a simple development board for the Atmel ATtiny861/461/261 and ATtiny167/87 parts, based on the same principles as my other boards. Pads are provided for a PTC polyfuse, SOT-223 regulator, capacitors, and an onboard LED. Spaces for ICSP header is provided for both x61 and x7, and for the x7, an FTDI header with DTR autoreset as well (the x61 does not have hardware serial). The pinouts of these boards are not identical, so two ICSP headers and two sets of pads for an external crystal are required; only one of each will be used. The x61 and x7 are two of the more exotic ATtiny processors; the x61 is made for driving brushless DC (BLDC) motors, having a PLL and high-speed timer with up to 6 outputs, while the x7 is equipped with a LIN interface (complete with 100uA current source for node identification) for automotive applications - the LIN/UART interface is also capable of much more precise baud rate generation. If you need one of those features, these are excellent microcontrollers for you; if you don't, you're probably better off with an ATtiny1634. These are now available assembled!
Required Components
- ATtiny x61 or x7
- 3x 0.1uf 1206 capacitors (2 for x61 or if not using autoreset)
- 10k 1206 resistor
- 1206 LED + appropriate resistor
- 0805-6032 capacitor for supply filter
- HC/49 Crystal (optional, up to 20mhz)
- 2x 0805 18pf ceramic capacitor (optional, for xtal)
- SOT-223 voltage regulator, like 1117-series (optional)
- 1x 1206 ceramic capacitor (optional, regulator input)
- 1x 1206 PTC Polyfuse (optional, regulator input)
- 0.1" pin header, 1x6 pins (FTDI header - for x7 only)
- 0.1" pin header, 2x3 pins (ICSP header)
- 2x 0.1" pin header, 1x12 pins
- 0.1" pin header, 1x2 pins (RST_EN - for x7 using autoreset only)
- 0.1" pin header or KK-100 connector, 1x2 pins (ext. power)
ATtiny 861/461/261 Features
- 8/4/2k Flash, 512/256/128b EEPROM, 512/256/128b SRAM
- PLL clock for operation at 16mhz without a crystal
- Hardware USI for SPI/I2C/etc
- 1 8/16 bit timer
- 1 8/10 bit high speed timer
- 3 PWM channels, normal and inverted outputs
- Programmable dead time generator
- Can run from PLL clock at 64mhz
- 14-bit prescaler
- PWM-6 mode for driving BLDC motor
- 15 GPIO pins + reset
- 11 analog inputs
- 16 differential input pairs
- Programmable gain: 1x, 8x, 20x or 32x
- on-chip analog comparator
- 1/8mhz (internal), 16mhz (internal PLL), up to 20mhz (external crystal)
ATTiny861 $15 Assembled
ATtiny 167/87 Features
- 16k/8k Flash, 512b EEPROM, 512b SRAM
- UART or LIN 2.1 / 1.3 controller
- Hardware SPI master/slave
- Hardware USI (for I2C/SPI/etc)
- 8-bit async timer
- 16-bit timer
- 15 GPIO pins + reset
- Advanced ADC
- 11 analog inputs
- 8 differential input pairs
- Programmable gain: 8x, 20x
- 100uA current source
- 8mhz (internal), up to 16mhz (external crystal)
- Optiboot bootloader support for Arduino on 87 and 167
ATTiny167 $18 Assembled
ATtiny x8/828 ATmega x8 breakout board - AZB-8
$2.75
This is a versatile breakout board that is compatible with most Atmel AVR processors in the TQFP-32 package. Pads for crystal, decoupling caps, and DTR autoreset components are provided. Programming headers are provided for the ATtiny88/48/828, as well as the ATmega x8 series (48,88,168 and the ever popular 328) and the new x8PB series. Where the chip has a hardware a serial port, an FTDI header is provided. Differences in the pinouts mean that two different ICSP and Serial headers are provided - one for the Tiny828, and one for everything else.
This board also provides a power supply section with pads for a supply filter cap from 0805 ceramic up to 3260 tant, a SOT-223 voltage regulator (like 1117 series), a 1206 input capacitor, and 2-pin external power input. Pads for a PTC polyfuse are also provided; this may be replaced with a 0 ohm resistor if the power supply is adequately protected against overcurrent conditions. Note that external power should not be connected while the board is powered from the FTDI or ISP header.
Supported Microcontrollers
- ATtiny 48 and 88 - use pin numbers on outside of top
- ATtiny 828 - use pin numbers on inside of top
- ATmega 48, 88, 168, 328 - use pin numbers on bottom
- ATmega 48PB, 88PB, 168PB - use pin numbers on bottom
Required Components
- Supported Atmel Microcontroller
- 0.1uf 1206 capacitors
- 2 for ATtiny x8
- 3 for ATtiny828, ATmega x8 PB
- 4 for ATmega x8
- 10k 1206 resistor
- 1206 LED + appropriate resistor
- 0805-6032 capacitor for power supply filter
- HC/49 Crystal (optional, up to 20mhz)
- 2x 0805 18pf ceramic capacitor (if using xtal)
- SOT-223 voltage regulator, like 1117-series (optional)
- 1x 1206 ceramic capacitor (if using regulator)
- 1x 1206 PTC Polyfuse (if using regulator)
- 0.1" pin header, 1x6 pins (FTDI header - for non-tiny48/88)
- 0.1" pin header, 2x3 pins (ICSP header)
- 2x 0.1" pin header, 1x19 pins
- 0.1" pin header, 1x2 pins (RST_EN - for non-tiny48/88)
- 0.1" pin header or KK-100 connector, 1x2 pins (optional, ext. power)
ATtiny 88/48 Features
- Very inexpensive
- 8/4k Flash, 64b EEPROM, 512/256b SRAM
- Hardware SPI master/slave
- Hardware I2C/TWI master/slave
- 1 8-bit timer (no PWM)
- 1 16-bit timer (2 PWM channels)
- 27 GPIO pins + reset
- 8 analog inputs
- Onboard analog comparator
- 1/8mhz (internal), up to 20mhz (external clock source - not crystal)
ATTiny88 $12 Assembled
ATtiny 828 Features
- 8k Flash, 256b EEPROM, 512b SRAM
- Hardware SPI master/slave
- Hardware I2C slave
- Hardware UART serial
- 1 8-bit, 1 16-bit timer (2 PWM channel each)
- 27 GPIO pins + reset
- 28 analog inputs
- Onboard analog comparator
- 1/8mhz (internal), up to 20mhz (external clock source - not crystal)
ATTiny828 $16 Assembled
ATmega 48/88/168/328 Features (shown on prototype version)
- 4/8/16/32k Flash, 256/512/512/1024b EEPROM, 512b/1k/1k/2k SRAM
- Hardware SPI master/slave
- Hardware I2C master/slave
- Hardware UART serial
- 2 8-bit, 1 16-bit timer (2 PWM channel each)
- 22 GPIO pins + reset
- 8 analog inputs
- Onboard analog comparator
- Supported by default arduino core
- 1/8mhz (internal), up to 20mhz (external crystal)
ATmega328p mounted on board (shown on prototype version)
ATmega 48/88/168PB Features
- 4/8/16k Flash, 256/512/512b EEPROM, 512b/1k/1k SRAM
- Hardware SPI master/slave
- Hardware I2C master/slave
- Hardware UART serial
- 2 8-bit, 1 16-bit timer (2 PWM channel each)
- 26 GPIO pins + reset
- 8 analog inputs
- Onboard analog comparator
- New version of the popular mega x8 series
- 1/8mhz (internal), up to 20mhz (external crystal)
ATMega168PB mounted on board (shown on prototype version)
Revision History
- Rev. A: Fixed silk screen. Tweaked routing around crystal, but no functional changes. Yellow solder mask.
- Rev. -: Silk screen messed up, not sold. Red solder mask.