Obsolete — sourcing the MSP430FG6426IZQWR today
BGA footprint and layout notes
The 113-ball Microstar Junior BGA (7x7 mm) is a fine-pitch package — ball pitch is 0.5 mm typical for this class. The 73 I/O lines fan out across the ball grid, so a four-layer board with a dedicated ground plane is advisable for signal integrity, especially when using the 16-bit ADC at full resolution.
20 MHz core and memory — what fits in the Flash
The 20 MHz clock rate is typical for the MSP430Xv2 architecture — enough for real-time control loops, sensor polling, and communication protocol handling without an external oscillator (the internal oscillator is included). The 128 KB Flash is generous for a 16-bit MCU; it can hold a full application stack including a real-time OS kernel, communication stacks, and calibration tables. The 10 KB RAM supports moderate data buffering — enough for a few hundred samples of 16-bit ADC data or a small display frame buffer. If your firmware needs more headroom, look at the higher-density MSP430F6xx variants, though they may come in different package options.