Pololu USB AVR Programmer v2.1

The Pololu USB AVR Programmer v2.1 is a compact, low-cost in-system programmer (ISP) for AVR microcontrollers from Atmel (now part of Microchip). The programmer provides an interface for transferring a compiled AVR program from your computer to the non-volatile memory of the target AVR so that it can run the program. It is a good solution for programming AVR-based controllers such as the A-Star 328PB Micro and Orangutan robot controllers. It can also be used to update, replace or remove the bootloader on Arduino boards and the Arduino-compatible A-Star controllers. This programmer was designed for use with 3.3 V and 5 V devices and can even be configured to power the target device in low-power systems.

The programmer communicates with your programming software, such as Atmel Studio, AVRDUDE or the Arduino IDE, via a virtual COM port using the STK500 protocol. The programmer connects to your target device via an included 6-pin ISP programming cable. The programmer also acts as a USB-to-TTL serial adapter, providing a TTL serial port that can be used to communicate with other serial devices from your computer. It is delivered with the connectors soldered on.

The Pololu USB AVR Programmer v2.1 is a drop-in replacement for the older Pololu USB AVR Programmer v2 with three hardware improvements:

• The optional VCC output feature of the v2 programmer (which lets you power your AVR target from the programmer) was not designed to supply loads with more than a few microfarads of capacitance. The v2.1 programmer has a better VCC output circuit, so it can power more powerful boards that would have caused the v2 programmer to repeatedly experience brownout resets. There is still a limit to the capacitance it can handle, but the v2.1 VCC output is expected to work with most small AVR target boards with less than about 33 ?F of capacitance on VCC.
• When you connected a v2 programmer to a 3pi robot, one of the motors could briefly run at full speed, because the programmer's circuit for measuring VCC could unintentionally pull up a programming pin of the 3pi before the GND connection was made. The v2.1 programmer has an improved circuit for measuring VCC that limits the duty cycle of this effect to about 0.2%, so the motor does not move (but it may produce a 25 Hz clicking noise).
• There was typically a brown-out when a 5 V signal was applied to its RST pin while it was operating at 3.3 V. The v2.1 programmer does not have this problem.

Features and specifications:

• Connects to a computer via USB using a USB A-to-Micro-B cable (not included)
• Emulates an STK500 programmer via a virtual COM port interface
• Works with standard AVR programming software, including Atmel Studio, AVRDUDE and the Arduino IDE
• Configuration software for Windows, Mac OS X and Linux
• Supports both 3.3 V and 5 V devices; can automatically switch the operating voltage based on the detected target VCC
• Can optionally power the target at 3.3 V or 5 V in low-power systems
• USB-to-TTL serial adapter functionality for general serial communication
• Provides a 100 kHz clock output, which can be useful for reviving misconfigured AVRs
• All I / O pins are protected with 470 ? resistors
• 6-pin ISP cable and a 1 × 6 double-sided male header included
• Comprehensive user guide