This version has a 5 V regulator that can be powered from 5.5 V to 15 V, and it features a 20 MHz resonator, which matches the voltage and clock speed of our Baby Orangutan B-328. It can be distinguished from other versions by its red power LED:
The A-Star 328PB ships with a preloaded Arduino-compatible TTL serial bootloader (which uses 0.5 KB of flash memory, leaving 31.5 KB available for the user program). We provide a software add-on that enables the board to be easily programmed from the Arduino environment.
Since the A-Star’s ATmega328PB microcontroller is backward-compatible with the ATmega328P commonly used on Arduino boards (like the Arduino Uno and Pro Mini), existing programs and libraries written for a standard Arduino can be used on the A-Star 328PB without any changes (except to account for clock speed differences when necessary). However, our add-on includes support for the new features on the ATmega328PB, making them easier to use from the Arduino environment and allowing the A-Star 328PB to be an upgrade from ATmega328P-based boards.
The A-Star 328PB is the same size as the Arduino Pro Mini. It can similarly be used as a compact, minimal alternative to a standard full-size Arduino, but since its pinout differs, this board is not a drop-in replacement for the Pro Mini.
Differences between the ATmega328P and ATmega328PB
Compared to the ATmega328P (and ATmega328), the ATmega328PB microcontroller offers a number of improvements, including:
- Two additional GPIO pins: PE0 and PE1
- Two pins that were previously analog inputs only (ADC6 and ADC7) can now also be used as digital inputs and outputs: PE2 and PE3
- Two additional 16-bit Timer/Counters: TC3 and TC4 (for a total of two 8-bit timers and three 16-bit timers)
- Three additional PWM output pins
- A second USART (TTL serial port)
- A second TWI (Two-Wire Serial Interface, I²C-compatible)
- A second SPI (Serial Peripheral Interface)
- A peripheral touch controller (PTC) for adding capacitive touch buttons, sliders, and wheels
The ATmega328PB is code-compatible with the ATmega328P, meaning code compiled for an ATmega328P will run as intended on an ATmega328PB. This application note (283k pdf) by Atmel (now part of Microchip) comprehensively describes the differences between the ATmega328PB and its predecessors.
Our Arduino software add-on makes it easy to use the additional GPIO functionality, PWM outputs, and TTL serial port. The other new features of the ATmega328PB can still be used from the Arduino environment through direct register access or custom libraries.
- Dimensions: 1.3? × 0.7?
- Programmable ATmega328PB AVR microcontroller
- 32 KB flash (0.5 KB used by bootloader, leaving 31.5 KB available for user program by default)
- 2 KB SRAM
- 1 KB EEPROM
- All I/O lines from the ATmega328PB broken out in a compact package
- 19 general-purpose I/O pins available along the sides of the board
- 5 additional I/O pins available on bottom edge
- 9 pins can be configured as hardware PWM outputs (7 along sides of board)
- 8 pins can be configured as analog inputs
- Preloaded with Arduino-compatible TTL serial bootloader
- 6-pin TTL serial programming header for use with a USB-to-serial adapter (we recommend our USB AVR Programmer v2, which can act as a USB-to-serial adapter)
- 6-pin ISP header for use with an external AVR programmer (we recommend our USB AVR Programmer v2)
- Power LED and user-controllable LED
- Reset button
- Two power options:
- 3.8 V to 15 V (3.3 V versions) or 5.5 V to 15 V (5 V versions) on BAT+
- USB-to-serial adapter can supply power to VCCIN on the serial header
- Reverse-voltage protection on BAT+ supply
Speed warning for 20 MHz version: The 20 MHz resonator frequency exceeds the maximum explicitly allowed in the ATmega328PB datasheet. In our basic testing, the 20 MHz resonator appears to function without problems, but for any critical applications you should confirm for yourself that this product is appropriate.
|Size:||0.7? × 1.3? × 0.1?|
|Processor:||ATmega328PB @ 20 MHz|
|RAM size:||2048 bytes|
|Program memory size:||32 Kbytes|
|User I/O lines:||24|
|Minimum operating voltage:||5.5 V|
|Maximum operating voltage:||15 V|
|Logic voltage:||5 V|
|Reverse voltage protection?:||Y|
|External programmer required?:||N|
|Version:||5 V logic, 20 MHz resonator|