Layer: L7 Application · Build flags: PC_ENABLE_HISLIP

What this example teaches

HiSLIP (High-Speed LAN Instrument Protocol, IVI-6.1) is VXI-11's higher-throughput successor and the current LXI transport for LAN test instruments. It carries SCPI over two TCP connections to port 4880 - a synchronous channel (the ordered SCPI command/response stream) and an asynchronous channel (out-of-band control: lock, status/SRQ, device-clear) - correlated by a 16-bit SessionID from the handshake. services/hislip is a pure codec: it builds and parses the fixed 16-byte message header and the handshake / data messages; the sketch owns the two sockets.

Every message is a 16-byte header ("HS" + message type + control code + 32-bit MessageParameter + 64-bit PayloadLength, all big-endian) optionally followed by a payload:

// Initialize the session (sync channel): offer v1.1, a vendor id, sub-address "hislip0"
size_t n = pc_hislip_build_initialize(buf, sizeof(buf), PC_HISLIP_VERSION_1_1, 0x4457, "hislip0");
// ...write, read the reply, parse it...
HislipInitializeResponse ir;
pc_hislip_parse_initialize_response(resp, PC_HISLIP_HEADER_LEN, &ir);   // ir.session_id

The second channel binds to the same session, then SCPI flows as Data / DataEND messages keyed by a MessageID:

pc_hislip_build_async_initialize(buf, sizeof(buf), ir.session_id);        // bind async channel
uint32_t id = PC_HISLIP_MESSAGE_ID_INIT;                                  // 0xFFFFFF00
pc_hislip_build_data(buf, sizeof(buf), /*is_end=*/true, 0, id, (const uint8_t *)"*IDN?\n", 6);
id = pc_hislip_next_message_id(id);                                       // += 2

The full HislipMsg message-type enum (0-38, including the HiSLIP 2.0 TLS / SASL types), the header byte layout, and the MessageID rule are verified against IVI-6.1. Pair with PC_ENABLE_SCPI to build / parse the SCPI payloads themselves (see the Scpi example).

Prerequisites (an instrument or a simulator)

Point INSTRUMENT_IP at anything that speaks HiSLIP on TCP 4880: a real LXI instrument, a Python pyvisa setup with a HiSLIP server, or the PyHiSLIP reference server for a dry run.

Build and run

pio ci --board=esp32dev --project-option="framework=arduino" \
  --project-option="build_flags=-DPC_ENABLE_HISLIP=1" \
  --lib="." examples/L7-Application/HiSlip/HiSlip.ino

Flash and watch Serial @ 115200:

IP: 192.168.1.42
[hislip] session=1 server-version=0x0101 overlap=0
[hislip] *IDN? -> KEYSIGHT TECHNOLOGIES,34470A,MY12345678,A.02.16
[hislip] done

Annotated source

The complete sketch is HiSlip.ino. The codec itself is in src/services/instrumentation/hislip/hislip.h; the header layout, message-type codes, and handshake vectors are verified against the IVI-6.1 HiSLIP 2.0 specification (cross-checked with the Wireshark dissector, MSL-equipment, and PyHiSLIP).