BWPA

BWPA is 8 bits wide on the SA-1, located at 2228h. It is initialized to FFh.

The Bit-Breakdown Diagram in the manual appears to suggest that zeros should be written to the high nybble.

All areas are write-protected on startup.

Reference

• 4.1.24 on page 1-4-17 of Book II of the official Super Nintendo development manual