This Drum is identified by the 6 bytes: 0000 A420 0111 at register address 0x(4)a400fa.
The Drum reports its information as a single byte of data, readable at 0x(4)a40005. The data is packed into the byte as follows (after decryption):
CL/R is the center of the drum (left/right side). RL/R is the rim of the drum (left/right side). These bits are inverted i.e. a hit clears the bit.
Note: The actual game performs a 6 byte read starting from address 0x00, but the first 5 bytes were not seen changing.