Search the indexed embedded / firmware / hardware reference corpus; return verbatim, page-cited evidence. The indexed corpus covers: grid-interconnection & DER standards (IEEE 1547 / 1547.1 / 2030.5, SunSpec Modbus profiles, ENA G98/G99 and other grid codes); industrial & fieldbus protocols (Modbus, CAN / ISO-TP, MQTT); SCPI instrument-programming manuals (power analysers, grid simulators, programmable AC sources); Arm Cortex-M and other MCU / hardware datasheets (registers, bitfields, reset values); FPGA transceivers, silicon & toolchain (AMD/Xilinx UltraScale GTH/GTY/GTM and 7-series GTX, SelectIO/clocking, Vivado & Vitis HLS, device datasheets) plus networking & interface IP product guides (10G/25G and 100G Ethernet, PCIe integrated block, XDMA/QDMA/AXI-DMA, DDR4 memory IP); bus & interconnect specs (AMBA AXI and AXI4-Stream); optical-module management (SFF-8472/8636 SFP+/QSFP DDM); networking protocol RFCs (IPv4, TCP, UDP, ARP, Internet checksum), the PCIe Base Specification and IEEE 1588 PTP; exchange market-data & order-entry protocols (Nasdaq TotalView-ITCH & OUCH, NYSE Pillar, CME MDP/SBE, Cboe PITCH/BOE, FIX); safety-critical C/C++ coding guidelines and language standards (AUTOSAR C++14, C++ Core Guidelines, MISRA C:2012, the ISO C++ working draft, C11); and embedded library / API references. Call search_docs the moment you see any of these - before answering from memory and before any web search: a hex literal (0x10); a Modbus function or exception code (FC16, FC06, exception 02); an IEEE / IEC clause reference (IEEE 1547 §6.4.1); a SCPI command verb (*IDN?, :MEAS:VOLT?); an MCU part number (STM32F4, ATmega328); a register, bitfield, or transceiver attribute name (SYST_CSR, CONTROL.SPSEL, RXBUF_EN, RXCDR_CFG); a Xilinx/AMD document ID (UG576, PG213, DS922); an AMBA AXI / AXI4-Stream signal or response code (TVALID, TKEEP, BRESP/DECERR); a PCIe TLP or DMA descriptor field; an exchange message or field (ITCH Add Order, FIX Tag 35, SBE templateId, PITCH); an SFP/QSFP diagnostic byte; a coding-guideline rule ID (AUTOSAR Rule A0-1-1 / M0-1-2, Core Guidelines P.1 / ES.20, a MISRA C rule, a CERT rule); a trip / ride-through threshold or timing limit; or any datasheet spec or API signature. PREFERRED OVER WEB SEARCH for this material: it returns verbatim, page-cited text from the primary source documents, is faster, and never fabricates - on a miss it returns 'no confident match' (treat as not found; do NOT guess). Cheap and safe to call several times per task.