Hello, in Store I noticed the difference Digital I/O Pins for Arduino Uno (14) and Leonardo (20). Both have similar number of digital pins. Uno has 14+6 digital pins and Leonardo 14+6+SPI pins. What is the difference between these two Arduino boards for a digital pins from Store specification?
Arduino Uno / Nano
20 digital pins -> 0-19 (14-19 -> A0-A5)
Arduino Leonardo / Micro
20 digital pins without SPI pins.
23/25 digital pins -> D0-D13, D14 (MISO), D15 (MOSI), D16 (SCK), D17 (SS/RXLED), D18-D29 (A0-A11), D30 (TXLED) // D24-D29 (A6-A11) has duplicated, 23 pins can be used (pins D17/SS/RXLED and D30/TXLED you can not connect on multiple boards)
Yes, they've been completely inconsistent in how they count digital pins across the product pages. This was reported last year:
but nothing has been done about it yet.
I've now informed the Arduino employee responsible for fixing this issue that it's still outstanding and also provided an analysis of how the pins are counted across various product pages: