Keep these rules aligned with the current Mitsubishi serial manuals and validated hardware results.

Address and Device Parsing

• ZR is decimal on the validated serial targets in this repo.
• R and ZR share the same internal register space on the validated RJ71C24-R2 target.
• X, Y, B, W, SB, SW, DX, and DY use hexadecimal address parsing.
• M, L, SM, F, V, D, SD, RD, S, Z, R, ZR, LTN, LSTN, LCN, and LZ use decimal address parsing.

Bit Packing

• Binary single-point bit reads return the addressed value in the high nibble.
• Binary single-point bit writes carry the addressed value in the high nibble.
• Binary word-unit bit-block packing uses bit0 -> LSB for the head device.
• Keep request-shape tests aligned with this rule before treating a mismatch as a hardware issue.

Long Timer and Counter Devices

• Treat LTS/LTC/LSTS/LSTC as structured data carried by LTN/LSTN 0401 responses.
• On the validated RJ71C24-R2 + R120PCPU setup:
  • the first two words of LTN/LSTN hold the current value
  • the third word holds contact/coil bits
  • 0x0001 = coil, 0x0002 = contact
• Do not treat direct LTS/LTC/LSTS/LSTC probes as part of the supported interface.

Qualified Access

• U...\\G... and U...\\HG... are supported only through the helper path built on 0601/1601.
• Native qualified commands remain diagnostic-only and are not part of the supported workflow.

FX5U Serial Scope

• On FX5UC-32MT/D serial 3C/4C, treat 0801/0802 as unsupported.
• On the same path, keep DX, DY, V, and ZR out of the validated contiguous subset.

Validation Discipline

• Check manual-backed request shape first.
• Then compare the local codec path.
• Then use hardware to break ties.
• Do not treat unsupported access paths as active holds.