A20-OLinuXino-LIME2 is with small compact design, this is why we couldn’t put on it all connectors for the functionality this board offers.
The existing 0.05″ step connectors are OK for cables and shields, but are pain when you want to breadboard something or to attach UEXT module.
This is why we made LIME2-SHIELD open source hardware shield. It has these signals available:
LIME2-SHIELD User manual explains how to prepare your SD-card for booting Linux on A20-OLinuXino-LIME2, then how to setup the board with different scripts and device tree.
Demo codes how to work with GPIO, I2C, SPI, CAN with C, Python and console are included:
olimex 
Jul 09, 2020 @ 21:49:30
Seems you’ve missed to include a link to the product page:
https://www.olimex.com/Products/OLinuXino/A20/LIME2-SHIELD/open-source-hardware
Jul 10, 2020 @ 12:12:26
Cool!
Does this board fit inside the lime2 box?
Jul 19, 2020 @ 12:14:45
If the CANbus transceiver is connected to the same pins as with the A20-CAN OLIMEX Expansion board, can4linux should work out of the box.