v1.3

• Change outer dimensions to fit to MTB-TTL.
• Add programming PCB
• Use ATmega328p.

v1.2

• Add 100k pull-up on TX_OE.

v1.1

• Free pin PB2 (used by SPI), move button to different pin.
• Enlarge drills for CPU socket 0.8 mm → 1.0 mm.
• Cover via with soldermask.

v1.0

Initial version.