'''
This protocol decoder de-multiplexes Intel MCS-48 (8039, 8048, etc.) external
-program memory accesses. This requires 14 channels: 8 for D0-D7 (data and
-lower 8 bits of address), 4 for A8-A11 (output on port P2), ALE and PSEN.
+program memory accesses.
+
+This requires 14 channels: 8 for D0-D7 (data and lower 8 bits of address),
+4 for A8-A11 (output on port P2), ALE and PSEN.
+
An optional A12 is supported, which may be an arbitrary I/O pin driven by
software (use case is dumping ROM of an HP 3478A).
'''