Skip to content

CLAUDE.md

Latest commit

 

History

History
53 lines (36 loc) · 3.15 KB

CLAUDE.md

File metadata and controls

53 lines (36 loc) · 3.15 KB

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Overview

Go package for communicating with Prologix GPIB-USB and GPIB-ETHERNET controllers, which bridge a computer to GPIB (IEEE 488) test instruments. Part of the gotmc ecosystem and designed to work with the ivi package for standardized instrument control. Requires Go 1.25+.

Build & Test Commands

# Format and vet (runs automatically before tests)
just check

# Run unit tests with coverage and race detection
just unit

# Lint with golangci-lint
just lint

# Run a single test
go test -run TestIsPrimaryAddressValid ./...

# HTML coverage report
just cover

# Run example (requires hardware): just key3631 /dev/ttyUSB0 5

just (Justfile) is the task runner; there is no Makefile.

Architecture

The package uses a layered design separating transport from GPIB protocol logic:

  • Transport layer (driver/): Provides io.ReadWriter implementations for different connection types. Currently only driver/vcp/ (Virtual COM Port via serial) is implemented. The driver/usb/ and driver/net/ directories are placeholders for future D2XX and Ethernet support.
  • Controller (controller.go): Core type wrapping any io.ReadWriter. Constructed via NewController() with functional options (WithSecondaryAddress, WithDebug, WithAR488). Handles GPIB address setup, controller initialization commands, and the ++ command prefix for Prologix-specific commands.
  • Commands (commands.go): Methods on Controller for Prologix ++ commands (e.g., ClearDevice, SetReadTimeout, Version, InstrumentAddress).
  • Examples (examples/vcp/): Working examples for real instruments (E3631A, DS345, Fluke 45, 33220A). All follow the same pattern: open VCP → create Controller → query version → run device commands → restore front panel → close.

Key design points:

  • Controller satisfies the ivi.Transport interface via Command, Query, ReadBinary, WriteBinary, and Close. It distinguishes between instrument communication (Command, Query, Write) and Prologix controller commands (CommandController, QueryController) which prepend ++.
  • Context-aware I/O: Controller checks if the underlying io.ReadWriter implements optional ContextReader/ContextWriter interfaces. If so, it delegates directly; otherwise it falls back to goroutine-based context handling.
  • The WithAR488() option skips verbose and savecfg commands for Arduino AR488 compatibility.
  • Query automatically sends ++read eoi when auto read-after-write is disabled.
  • Binary data methods (Write/Read) vs string methods (WriteString, Command, Query) handle GPIB character escaping differently. Prologix strips unescaped LF, CR, ESC, and + characters, so Write escapes them automatically.
  • VCP serial config is hardcoded to Prologix defaults: 115200 baud, 7 data bits, even parity, 1 stop bit.

Dependencies

  • github.com/gotmc/query — SCPI query helpers
  • go.bug.st/serial — cross-platform serial port access
  • go.uber.org/multierr — error combining