12 MHz, 2 KB flash — the tinyAVR BOM-fit check
The Microchip ATTINY20-CCUR is an 8-bit AVR MCU in the ATtiny family, built for small-footprint, low-pin-count embedded control. It runs at 12 MHz, carries 2 KB of program flash, and 128 bytes of SRAM. The 12 I/O lines include an I²C and SPI interface, plus an 8-channel 10-bit ADC.
Memory headroom — the hard constraint
The 2 KB flash is the first thing to check: a compiled binary for a sensor hub or a simple PWM controller with an I²C bootloader typically lands around 1.2–1.6 KB, leaving 400–800 bytes for future patches. The 128-byte SRAM is the tighter constraint — a single 64-byte I²C receive buffer consumes half of it. Any application with interrupt nesting, multiple ring buffers, or a real-time OS will overflow this part.
15-ball UFBGA — rework and footprint
The 15-UFBGA package measures 3x3 mm — a tiny BGA with 0.5 mm ball pitch typical for this class. The 0.5 mm pitch rules out hand-soldering and two-layer board fan-out without vias.