modem_at_demo Directory Reference

Directory dependency graph for modem_at_demo:

Directories
	src

Detailed Description

Drives the libs/ra8_modem_at cellular AT command/response driver against a 3GPP AT-command modem (SIM7600 / Quectel BG95 class) over the MikroBUS UART on SCI channel 7 (#259) – a MikroE cellular Click presents its modem UART on exactly those pads.

It brings SCI7 up, registers a +CREG URC handler, and walks a small state machine: probe and disable echo and select numeric CME errors; check the SIM; read signal strength; enable and poll registration; check PS attach. The last step is the interesting one – it issues a command the modem does not support and treats the resulting +CME ERROR as the expected outcome, so the error path through the driver is asserted rather than merely avoided. Any unexpected step failure latches LED2 and parks.

The app uses the central ra8_board_* console and MikroBUS pin helpers rather than hand-encoded pins, and it carries no per-app boot files or linker script: cmake/ra8_add_app.cmake supplies the shared startup and the canonical single-core linker script, so only src/main.c is app-specific. The compound decisions – registration OK, signal valid, per-step expected outcome, overall verdict – are host-tested with MC/DC in tests/mocks/src/test_app_modem_at_demo.c.

Blocked on

A live cellular modem on the wire: a populated MikroBUS cellular Click with a provisioned SIM and an antenna, none of which is on the bench.

The AT protocol itself is faithfully modelled off-target – an SCI7 AT-responder answers the exact script above, including the +CREG URC and the +CME ERROR for the unsupported command – so ra8_modem_at -> ra8_sci runs byte-for-byte as it would on silicon and the state machine completes with zero skips. Only the RF link is unmodelled, and the antenna is the only unproven link in the chain.