OLIMEX© 2014
AVR-T32U4 user's manual
If you want to upgrade the bootloader, or program the board without the ARDUINO-IDE there are
pinouts for ICSP programmer (note that there IS a 6-pin connector mounted). You can use our AVR-
ISP-ISO, or AVR-ISP-TINY programmer for custom programming without ARDUINO IDE.
Having an AVR programmer is highly advisable since the bootloader software is still not perfect
and it is possible to destroy it only by software means (for instance disabling all interrupts and then
entering infinite loop would hang the bootloader) which would require reinstalling the bootloader.
3.3 Powering the board
The AVR-T32U4 board is self-powered by the miniUSB if it is connected to a USB hub of a
computer.
Alternatively it can be powered via the power pins located at the bottom of the board. You may
provide between 3.0V and 5V on one of those proto power pins to power the board. Additionally, if
the board is powered by USB you might find 3.3V out on those same pins. Please check the picture
above - the lines that might be used for powering connect at the breadboard at the “+” and “-” lines.
IMPORTANT – DO NOT POWER AVR-T32U4 FROM BOTH THE USB AND THE PROTO
POWER PINS SIMULTANEOUSLY. THIS WOULD LEAD TO SHORT CIRCUIT OR
OVERVOLTAGE!
The bootloader starts automatically.
On powering the board PWR_LED should turn on. RXLED and TXLED should turn on and
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