fix(protocol): implement auto-detection of frame mode based on probe response size for accurate chunk handling

minimateplus/protocol.py

@@ -614,6 +614,34 @@ class MiniMateProtocol:
             [f"0x{f.page_key:04X}" for f in probe_batch],
         )
 
+        # Auto-detect frame mode from probe response size.
+        #
+        # Two observed TCP modes (confirmed from 4-26-26 and 4-27-26 captures):
+        #
+        #   1-frame mode (RS-232 / fast TCP): probe returns 1 large frame (~1100 B).
+        #     Each subsequent chunk also returns 1 large frame.  The probe contributes
+        #     ~999 bytes of ADC body data.  The correct term_counter = metadata_counter
+        #     + 0x0400, which returns ~702 bytes of tail+footer — NO extra chunk needed.
+        #
+        #   2-frame mode (TCP frame-splitting): probe returns 1 smaller frame (~554 B).
+        #     Each subsequent chunk returns 2 smaller frames (~550 B each).  The probe
+        #     contributes only ~487 bytes.  The missing ~512 bytes of body data must come
+        #     from an extra chunk after metadata, terminating at metadata_counter+0x0800.
+        #     The caller's extra_chunks_after_metadata value (default 1) covers this.
+        #
+        # Threshold 700 B sits comfortably between the two observed probe sizes (554 vs
+        # 1097 bytes) and is robust to minor variation.
+        _probe_is_large = (
+            len(probe_batch) == 1 and len(probe_batch[0].data) >= 700
+        )
+        _effective_extra_chunks = 0 if _probe_is_large else extra_chunks_after_metadata
+        log.warning(
+            "5A probe data_len=%d  _probe_is_large=%s  effective_extra_chunks=%d",
+            len(probe_batch[0].data),
+            _probe_is_large,
+            _effective_extra_chunks,
+        )
+
         # ── Step 2: chunk loop ───────────────────────────────────────────────
         # Counter formula: _chunk_base + (chunk_num - 1) * 0x0400
         # where _chunk_base = max(key4[2:4], 0x0400).
@@ -686,8 +714,8 @@ class MiniMateProtocol:
                 # (confirmed 2026-04-23).  The extra chunk data also belongs in the
                 # file body (confirmed from TCP capture analysis 2026-04-27).
                 log.debug("5A metadata found — fetching %d more chunk(s)",
-                          extra_chunks_after_metadata)
-                for _extra_n in range(extra_chunks_after_metadata):
+                          _effective_extra_chunks)
+                for _extra_n in range(_effective_extra_chunks):
                     chunk_num += 1
                     counter = _chunk_base + (chunk_num - 1) * _BULK_COUNTER_STEP
                     params = bulk_waveform_params(key4, counter)