How can you tell by looking at the board if your Olimexino-32U4 is Rev.A or Rev.A3? The difference is that D14 and D17 have switched roles. On Rev.A D17 goes to UEXT pin 7 i.e. MISO, but on Rev.A3 to RXLED.
I have Rev.A3, but I determined that by blinking RXLED.
We are currently manufacturing hardware revision B of OLIMEXINO-32u4. I would update the files as soon as possible.
What is printed on the top of the board right from the lion logo? It is says revision "A" and you purchased the board in or after 2014, then it is hardware revision A3.
It seems you can't easily see a difference between the boards for Rev.A and Rev.A3.
What is the difference between Rev.A3 and Rev.B?
This file is not updated with Rev.B: https://www.olimex.com/Products/Duino/AVR/OLIMEXINO-32U4/resources/OLIMEXINO-32U4.pdf
Check OLIMEXINO-32U4_revision.txt inside this archive: https://www.olimex.com/Products/Duino/AVR/OLIMEXINO-32U4/resources/OLIMEXINO-32U4_brd_sch_B.zip
It says:
"Changes in hardware revision B
============
1. FET1's drain and source ware swapped. When external power supply and USB are present, there will be current injected in the USB from the external power supply through the FET1's internal diode!"
I suppose it should say "drain and source were swapped". Does the next sentence describe how it was in Rev.A3 or how it is in Rev.B?
Does the next sentence describe how it was in Rev.A3 or how it is in Rev.B?
In old revision. The spelling and sequence of tenses are fixed now.