honor EOM bit, drain multi-packet bulk-IN responses#12
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doReadsent a singleREQUEST_DEV_DEP_MSG_INper call and trusted the USBTMC header'stransfer_size, so devices that split a response across multiple messages withEOM=0returned only the first chunk.The Rigol DS1102Z-E hits this on
:WAV:DATA?: it caps each response at one bulk-IN packet, misreportstransfer_size, and never setsEOM=1, terminating with a ZLP instead. Previously returned 500 bytes where 1200 were expected.The fix loops on
REQUEST_DEV_DEP_MSG_INuntilEOM=1or the buffer is full, and drains any extra bulk-IN packets queued past the declaredtransfer_sizeon the first iteration, stopping on ZLP. The timeout is a safety net for devices that go silent rather than sending a ZLP.The stale bTag tolerance (isContinuationHeaderMismatch) was required to get correct reads on the DS1102Z-E — the device echoes the previous bTag in continuation responses.
Tested on Rigol DS1102Z-E, firmware
00.06.04(current latest).Drafted with Claude Opus 4.7 (xhigh effort); reviewed, tested, and verified on hardware by me.