Cellular AT-modem bring-up + query demo over the MikroBUS UART (SCI7). More...

#include <stddef.h>
#include <stdint.h>
#include "ra8_board_ek_ra8d2.h"
#include "ra8_boot_entry.h"
#include "ra8_cgc.h"
#include "ra8_err.h"
#include "ra8_gpio_constants.h"
#include "ra8_isr.h"
#include "ra8_modem_at.h"
#include "ra8_mstp.h"
#include "ra8_port_utils.h"
#include "ra8_sci.h"
#include "ra8_time.h"

Include dependency graph for main.c:

Enumerations
enum	modem_const_t : uint32_t { k_modem_baud = 115200U , k_modem_console_baud = 115200U , k_modem_heartbeat_ms = 500U , k_modem_dec_base = 10U , k_modem_uart_channel = (uint32_t)k_ra8_board_mikrobus_uart_sci_channel }
	App-wide numeric tunables (typed enum – no magic numbers). More...
enum	modem_timeout_t : uint16_t { k_modem_cmd_timeout_ms = 2000U }
	Per-command timeout handed to ra8_modem_at (ms). More...
enum	modem_cap_t : uint32_t { k_modem_dec_cap = 10U , k_modem_capture_cap = 64U , k_modem_scan_max = 64U }
	Small fixed buffer capacities. More...
enum	modem_csq_t : uint8_t { k_modem_csq_min_bars = 5U , k_modem_csq_max = 31U , k_modem_csq_unknown = 99U }
	CSQ (signal-quality) sentinels: RSSI range 0..31, 99 = unknown. More...
enum	modem_creg_stat_t : uint8_t { k_modem_creg_not_registered = 0U , k_modem_creg_home = 1U , k_modem_creg_searching = 2U , k_modem_creg_denied = 3U , k_modem_creg_unknown = 4U , k_modem_creg_roaming = 5U }
	+CREG registration-status codes (3GPP 27.007). More...
enum	modem_cgatt_t : uint8_t { k_modem_cgatt_detached = 0U , k_modem_cgatt_attached = 1U }
	CGATT PS-attach flag values. More...

Functions
static bool	modem_creg_registered (uint32_t stat)
	Is the modem registered on a network (home or roaming)?
static bool	modem_signal_valid (uint32_t rssi)
	Is a CSQ RSSI reading a known, usable signal?
static bool	modem_step_passed (bool is_cme_probe, ra8_err_t err)
	Did an AT step return the outcome the app expected?
static bool	modem_run_ok (bool sim_ready, bool signal_ok, bool registered, bool attached, bool cme_ok)
	Overall run verdict: every probed condition must hold.
static bool	modem_parse_first_uint (const char line, uint32_t out)
	Parse the first unsigned integer after the : in an AT reply line.
static bool	modem_parse_last_uint (const char line, uint32_t out)
	Parse the LAST unsigned integer anywhere in an AT reply line.
static bool	modem_line_contains (const char line, const char needle)
	Does `line` contain the substring `needle`?
static uint32_t	modem_u32_to_dec (uint32_t value, uint8_t *out)
	Convert an unsigned 32-bit int into a decimal ASCII string.
static void	modem_tx (const uint8_t *bytes, uint32_t len)
	Emit a byte run on the J-Link OB VCOM console (SCI8).
static void	modem_emit_kv (const uint8_t *label, uint32_t label_len, uint32_t value)
	Emit a labelled unsigned integer: <label><value>.
static ra8_err_t	modem_tx_byte (void *ctx, uint8_t byte)
static ra8_err_t	modem_rx_byte (void ctx, uint8_t out_byte)
static uint32_t	modem_now_ms (void *ctx)
static void	modem_on_creg_urc (const char line, void ctx)
	URC handler for unsolicited + solicited +CREG lines.
static void	modem_panic_halt (void)
	Park forever after a fatal error.
static void	modem_clocks_or_halt (uint32_t *out_pclka_hz)
	Bring CGC + SysTick + MSTP up; publish PCLKA via `out_pclka_hz`.
static void	modem_pfs_or_halt (void)
	Route the MikroBUS UART pins (TXD7 / RXD7) via PFS.
static void	modem_setup_or_halt (void)
	Bring CGC + console (SCI8) + modem UART (SCI7) + LEDs up.
static ra8_err_t	modem_bind (uint8_t *line_buf, uint16_t line_buf_len)
	Bind ra8_modem_at to the SCI7 transport + register the URC handler.
static ra8_err_t	modem_cmd_ok (const char *cmd)
	Send an AT command and require a bare OK.
static ra8_err_t	modem_query (const char cmd, char buf, size_t cap)
	Send an AT query and capture its response payload.
static void	modem_fail (const uint8_t *step, uint32_t step_len)
	Print a modem: <step> FAIL banner, latch LED2, and park.
static void	modem_phase_sync (void)
	Sync phase: probe (AT), disable echo (ATE0), numeric CME errors.
static bool	modem_phase_sim (void)
	SIM phase: query AT+CPIN? and confirm READY.
static bool	modem_phase_signal (uint32_t *out_rssi)
	Signal phase: query AT+CSQ and parse + print the RSSI.
static bool	modem_phase_registration (void)
	Registration phase: enable +CREG URCs, poll one, then query.
static bool	modem_phase_attach (void)
	Attach phase: query AT+CGATT? and parse + print the flag.
static bool	modem_phase_error (void)
	Error-path phase: send an unsupported command, expect +CME ERROR.
void	main (void)
	Application entry: bring up SCI7 + the AT driver, walk the state machine.

Variables
static uint8_t	s_creg_stat
	Latest registration status parsed from a +CREG line.
static bool	s_creg_seen
	True once at least one +CREG line has been parsed.
static const uint8_t	k_modem_banner_prefix [] = "modem: rssi="
static const uint8_t	k_modem_str_reg [] = " reg="
static const uint8_t	k_modem_str_attach [] = " attach="
static const uint8_t	k_modem_str_cme [] = " cme="
static const uint8_t	k_modem_str_ok [] = "ok"
static const uint8_t	k_modem_str_no [] = "no"
static const uint8_t	k_modem_str_pass [] = " PASS\r\n"
static const uint8_t	k_modem_str_fail [] = " FAIL\r\n"

Detailed Description

Cellular AT-modem bring-up + query demo over the MikroBUS UART (SCI7).

Tag: [Ring 6 / APP] {World: S}

Stand-alone EK-RA8D2 application that drives libs/ra8_modem_at against a 3GPP AT-command cellular modem (SIM7600 / Quectel BG95 class) presented on the MikroBUS UART – RXD7 / TXD7, i.e. SCI channel 7 (k_ra8_board_mikrobus_uart_sci_channel). A MikroE cellular Click (LTE IoT / 4G LTE / NB-IoT) exposes its modem on exactly these MikroBUS pads.

TODO(real modem): the physical RF link + a populated MikroBUS cellular Click with a live SIM are external hardware this repo cannot carry, so the app is hw_pending. ra8_emulator answers the AT script faithfully with the SCI7 modem model (tools/ra8_emulator/src/periph/board_periph_modem.c, --modem), so the app boots and walks its whole state machine 0-skip in EIL (EIL == HIL for the AT protocol; only the antenna is unmodelled).

State machine (each step is one blocking ra8_modem_at command):

sync : AT / ATE0 / AT+CMEE=1 (probe, no-echo, numeric CME errors).
SIM : AT+CPIN? -> expect +CPIN: READY.
signal : AT+CSQ -> parse RSSI (0..31, 99 = unknown).
registration : AT+CREG=1 then poll the unsolicited +CREG URC, then AT+CREG? -> registration status (1 home / 5 roam).
attach : AT+CGATT? -> PS attach flag.
error path : an unsupported command -> the modem replies +CME ERROR: 4; the driver surfaces k_ra8_err_hw_error and the app treats that as the EXPECTED outcome for this step.

On success the app prints (SCI8 console, scraped by ra8_emulator / a HIL rig):

modem: rssi=17 reg=1 attach=1 cme=ok PASS

On any unexpected step failure it prints modem: <step> FAIL, latches LED2 and parks. 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.

Copyright: Copyright (c) 2026 Brighton Sikarskie SPDX-License-Identifier: MIT

Since: 0.1.0

Definition in file main.c.

Enumeration Type Documentation

◆ modem_cap_t

enum modem_cap_t : uint32_t

Small fixed buffer capacities.

Enumerator
k_modem_dec_cap	Digits for a uint32_t decimal (+ slack).
k_modem_capture_cap	Capture buffer for one response payload.
k_modem_scan_max	Static bound for every line-scan loop.

Definition at line 85 of file main.c.

◆ modem_cgatt_t

enum modem_cgatt_t : uint8_t

CGATT PS-attach flag values.

Enumerator
k_modem_cgatt_detached	Not attached to the PS domain.
k_modem_cgatt_attached	Attached to the PS domain.

Definition at line 109 of file main.c.

◆ modem_const_t

enum modem_const_t : uint32_t

App-wide numeric tunables (typed enum – no magic numbers).

Enumerator
k_modem_baud	SIM7600/BG95 default line rate.
k_modem_console_baud	J-Link OB VCOM console line rate.
k_modem_heartbeat_ms	LED heartbeat period after PASS.
k_modem_dec_base	Radix for integer-to-ASCII.
k_modem_uart_channel	SCI7.

Definition at line 70 of file main.c.

◆ modem_creg_stat_t

enum modem_creg_stat_t : uint8_t

+CREG registration-status codes (3GPP 27.007).

Enumerator
k_modem_creg_not_registered	Not registered, not searching.
k_modem_creg_home	Registered, home network.
k_modem_creg_searching	Not registered, searching.
k_modem_creg_denied	Registration denied.
k_modem_creg_unknown	Unknown (e.g. out of coverage).
k_modem_creg_roaming	Registered, roaming.

Definition at line 99 of file main.c.

◆ modem_csq_t

enum modem_csq_t : uint8_t

CSQ (signal-quality) sentinels: RSSI range 0..31, 99 = unknown.

Enumerator
k_modem_csq_min_bars	Minimum RSSI treated as a usable signal.
k_modem_csq_max	Highest valid CSQ RSSI index.
k_modem_csq_unknown	CSQ "not known / not detectable".

Definition at line 92 of file main.c.

◆ modem_timeout_t

enum modem_timeout_t : uint16_t

Per-command timeout handed to ra8_modem_at (ms).

Enumerator
k_modem_cmd_timeout_ms	Modem cmd timeout ms.

Definition at line 80 of file main.c.

Function Documentation

◆ main()

void main ( void )

Application entry: bring up SCI7 + the AT driver, walk the state machine.

The application entry point Reset_Handler hands control to.

Precondition: Reset_Handler has copied .data and zeroed .bss.; SystemInit has set VTOR, FPU, and priority grouping.

Postcondition: On a clean run the PASS banner is printed and the CPU heartbeats forever.; On any failure LED2 latches ON and the CPU parks.

Since: 0.1.0

Definition at line 891 of file main.c.

References k_modem_capture_cap, k_modem_csq_unknown, k_modem_heartbeat_ms, k_modem_str_cme, k_modem_str_fail, k_modem_str_no, k_modem_str_ok, k_modem_str_pass, k_ra8_board_led1, k_ra8_ok, modem_bind(), modem_fail(), modem_panic_halt(), modem_phase_attach(), modem_phase_error(), modem_phase_registration(), modem_phase_signal(), modem_phase_sim(), modem_phase_sync(), modem_run_ok(), modem_setup_or_halt(), modem_tx(), ra8_board_led_toggle(), ra8_delay_ms(), and ra8_isr_globals_enable().

◆ modem_bind()

ra8_err_t modem_bind	(	uint8_t *	line_buf,
		uint16_t	line_buf_len )

static

Bind ra8_modem_at to the SCI7 transport + register the URC handler.

Parameters

[in]	line_buf	Caller-owned line accumulator for the driver.
[in]	line_buf_len	Capacity of `line_buf`.

Returns: ra8_err_t from init / handler registration.

Return values

k_ra8_ok	Bound and the +CREG handler is installed.
other	The first non-OK code from init / registration.

Precondition: line_buf is non-NULL and line_buf_len >= 16.; SCI7 is initialised.

Postcondition: On success the driver is ready and the URC handler is live.; On failure the driver is left uninitialised.

Since: 0.1.0

Definition at line 651 of file main.c.

References k_modem_cmd_timeout_ms, k_ra8_ok, modem_now_ms(), modem_on_creg_urc(), modem_rx_byte(), modem_tx_byte(), ra8_modem_at_init(), and ra8_modem_at_register_unsolicited_handler().

Referenced by main().

◆ modem_clocks_or_halt()

void modem_clocks_or_halt ( uint32_t * out_pclka_hz )

static

Bring CGC + SysTick + MSTP up; publish PCLKA via out_pclka_hz.

Parameters

[out] out_pclka_hz Receives the live PCLKA frequency on success.

Precondition: IRQs masked or single-threaded init context.; out_pclka_hz is non-NULL.

Postcondition: On success *out_pclka_hz is non-zero and CGC/MSTP/SysTick are live.; On any failure the function never returns (parks).

Since: 0.1.0

Definition at line 555 of file main.c.

References k_ra8_clock_id_cpuclk0, k_ra8_clock_id_pclka, k_ra8_ok, modem_panic_halt(), ra8_cgc_get_clock_hz(), ra8_cgc_init(), ra8_mstp_init(), and ra8_time_init().

Referenced by modem_setup_or_halt().

◆ modem_cmd_ok()

ra8_err_t modem_cmd_ok ( const char * cmd )

static

Send an AT command and require a bare OK.

Parameters

[in] cmd NUL-terminated AT command (no trailing CR).

Returns: The ra8_modem_at_send_cmd return code.

Precondition: The driver was bound by modem_bind.; cmd is NUL-terminated.

Postcondition: The command has been transmitted and its result awaited.; No app state is mutated here.

Since: 0.1.0

Definition at line 682 of file main.c.

References k_modem_cmd_timeout_ms, and ra8_modem_at_send_cmd().

Referenced by modem_phase_error(), modem_phase_registration(), and modem_phase_sync().

◆ modem_creg_registered()

bool modem_creg_registered ( uint32_t stat )

static

Is the modem registered on a network (home or roaming)?

Parameters

[in] stat A +CREG status code (modem_creg_stat_t value).

Returns: true iff stat is "registered, home" or "registered, roaming".

Return values

true	`stat` == 1 or `stat` == 5.
false	Any other status (not registered / searching / denied / unknown).

Precondition: stat is a 3GPP 27.007 +CREG status code.; No shared state is read.

Postcondition: No state is mutated.; Return value depends solely on stat.

Note: Pure function; thread-safe.

Since: 0.1.0

Definition at line 170 of file main.c.

References k_modem_creg_home, and k_modem_creg_roaming.

Referenced by modem_phase_registration().

◆ modem_emit_kv()

void modem_emit_kv	(	const uint8_t *	label,
		uint32_t	label_len,
		uint32_t	value )

static

Emit a labelled unsigned integer: <label><value>.

Parameters

[in]	label	NUL-terminated label bytes.
[in]	label_len	Length of `label` in bytes.
[in]	value	Value to print in decimal.

Precondition: label is non-NULL.; The console was initialised.

Postcondition: <label><value> has been transmitted on SCI8.; No app state is mutated.

Since: 0.1.0

Definition at line 462 of file main.c.

References k_modem_dec_cap, modem_tx(), and modem_u32_to_dec().

Referenced by modem_phase_attach(), modem_phase_registration(), and modem_phase_signal().

◆ modem_fail()

void modem_fail	(	const uint8_t *	step,
		uint32_t	step_len )

static

Print a modem: <step> FAIL banner, latch LED2, and park.

Parameters

[in]	step	NUL-terminated failing-step label.
[in]	step_len	Length of `step` in bytes.

Precondition: The console is initialised.

Postcondition: The FAIL banner is emitted, LED2 is ON, and the CPU parks.; The function never returns.

Since: 0.1.0

Definition at line 719 of file main.c.

References k_ra8_board_led2, modem_panic_halt(), modem_tx(), and ra8_board_led_on().

Referenced by main(), modem_phase_attach(), modem_phase_registration(), modem_phase_signal(), modem_phase_sim(), and modem_phase_sync().

◆ modem_line_contains()

bool modem_line_contains	(	const char *	line,
		const char *	needle )

static

Does line contain the substring needle?

Parameters

[in]	line	NUL-terminated line to search (may be NULL -> false).
[in]	needle	NUL-terminated substring (may be NULL -> false).

Returns: true iff needle occurs within line.

Return values

true	A match was found.
false	No match, or a NULL argument.

Precondition: Both strings are NUL-terminated within k_modem_scan_max bytes.; No shared state is read.

Postcondition: No state is mutated.

Note: Pure function; thread-safe.

Since: 0.1.0

Definition at line 373 of file main.c.

References k_modem_scan_max.

Referenced by modem_phase_sim().

◆ modem_now_ms()

uint32_t modem_now_ms ( void * ctx )

static

Definition at line 487 of file main.c.

References ra8_now_ms().

Referenced by modem_bind().

◆ modem_on_creg_urc()

void modem_on_creg_urc	(	const char *	line,
		void *	ctx )

static

URC handler for unsolicited + solicited +CREG lines.

Parses the registration status (last integer field) and latches it for the run verdict. Registered with ra8_modem_at_register_unsolicited_handler so both the AT+CREG=1 enable URC and the AT+CREG? reply route here.

Parameters

[in]	line	NUL-terminated +CREG ... line (non-NULL from the driver).
[in]	ctx	Unused opaque context.

Precondition: line is a NUL-terminated modem line beginning with +CREG:.; The module s_creg_stat / s_creg_seen are single-owner.

Postcondition: On a parseable status, s_creg_stat / s_creg_seen are updated.; No transmit occurs from within the handler.

Note: Not thread-safe; the demo is single-threaded.

Since: 0.1.0

Definition at line 511 of file main.c.

References modem_parse_last_uint(), s_creg_seen, and s_creg_stat.

Referenced by modem_bind().

◆ modem_panic_halt()

void modem_panic_halt ( void )

static

Park forever after a fatal error.

Precondition: Called only after a fatal init/step failure.

Postcondition: The CPU is parked; only a debugger or reset wakes it.

Since: 0.1.0

Definition at line 536 of file main.c.

Referenced by main(), modem_clocks_or_halt(), modem_fail(), modem_pfs_or_halt(), and modem_setup_or_halt().

◆ modem_parse_first_uint()

bool modem_parse_first_uint	(	const char *	line,
		uint32_t *	out )

static

Parse the first unsigned integer after the : in an AT reply line.

Used for +CSQ: 17,99 (-> 17) and +CGATT: 1 (-> 1). Every scan loop is bounded by k_modem_scan_max (NASA P10 Rule 2).

Parameters

[in]	line	NUL-terminated reply line (may be NULL -> failure).
[out]	out	Parsed value on success (may be NULL -> failure).

Returns: true iff a colon-delimited unsigned integer was parsed.

Return values

true	`out` holds the first integer after the colon.
false	No colon, no digit, or a NULL argument.

Precondition: line is NUL-terminated within k_modem_scan_max bytes.; out points to writable storage when non-NULL.

Postcondition: out is written only on success.; No other state is mutated.

Note: Pure function; thread-safe.

Since: 0.1.0

Definition at line 282 of file main.c.

References k_modem_dec_base, and k_modem_scan_max.

Referenced by modem_phase_attach(), and modem_phase_signal().

◆ modem_parse_last_uint()

bool modem_parse_last_uint	(	const char *	line,
		uint32_t *	out )

static

Parse the LAST unsigned integer anywhere in an AT reply line.

The +CREG status is the last field in both forms the modem sends: the URC +CREG: <stat> and the solicited +CREG: <n>,<stat>. Scanning for the last digit run yields stat for both. Bounded by k_modem_scan_max.

Parameters

[in]	line	NUL-terminated reply line (may be NULL -> failure).
[out]	out	Parsed value on success (may be NULL -> failure).

Returns: true iff at least one digit run was found.

Return values

true	`out` holds the value of the last digit run.
false	No digit found, or a NULL argument.

Precondition: line is NUL-terminated within k_modem_scan_max bytes.; out points to writable storage when non-NULL.

Postcondition: out is written only on success.; No other state is mutated.

Note: Pure function; thread-safe.

Since: 0.1.0

Definition at line 331 of file main.c.

References k_modem_dec_base, and k_modem_scan_max.

Referenced by modem_on_creg_urc().

◆ modem_pfs_or_halt()

void modem_pfs_or_halt ( void )

static

Route the MikroBUS UART pins (TXD7 / RXD7) via PFS.

Precondition: ra8_mstp_init already ran so PFS writes land.

Postcondition: Both SCI7 UART pins are in their peripheral PSEL on success.; On any failure the function never returns (parks).

Since: 0.1.0

Definition at line 584 of file main.c.

References k_ra8_board_mikrobus_rx, k_ra8_board_mikrobus_tx, k_ra8_ok, k_ra8_psel_sci_async, modem_panic_halt(), and ra8_pfs_route_peripheral().

Referenced by modem_setup_or_halt().

◆ modem_phase_attach()

bool modem_phase_attach ( void )

static

Attach phase: query AT+CGATT? and parse + print the flag.

Returns: true iff the modem reported PS-attached (flag == 1).

Precondition: The driver was bound.

Postcondition: On query failure the function never returns.; attach= is emitted with the parsed flag.

Since: 0.1.0

Definition at line 846 of file main.c.

References k_modem_capture_cap, k_modem_cgatt_attached, k_modem_cgatt_detached, k_modem_str_attach, k_ra8_ok, modem_emit_kv(), modem_fail(), modem_parse_first_uint(), and modem_query().

Referenced by main().

◆ modem_phase_error()

bool modem_phase_error ( void )

static

Error-path phase: send an unsupported command, expect +CME ERROR.

Returns: true iff the driver surfaced the expected k_ra8_err_hw_error.

Precondition: The driver was bound and AT+CMEE=1 enabled numeric CME errors.

Postcondition: No console output here (the verdict banner reports cme=).; No app state is mutated.

Since: 0.1.0

Definition at line 870 of file main.c.

References modem_cmd_ok(), and modem_step_passed().

Referenced by main().

◆ modem_phase_registration()

bool modem_phase_registration ( void )

static

Registration phase: enable +CREG URCs, poll one, then query.

Returns: true iff the latched registration status is home or roaming.

Precondition: The driver was bound with the +CREG URC handler installed.

Postcondition: On any command failure the function never returns.; s_creg_stat reflects the latest +CREG line; reg= is emitted.

Since: 0.1.0

Definition at line 820 of file main.c.

References k_modem_str_reg, k_ra8_ok, modem_cmd_ok(), modem_creg_registered(), modem_emit_kv(), modem_fail(), ra8_modem_at_poll(), s_creg_seen, and s_creg_stat.

Referenced by main().

◆ modem_phase_signal()

bool modem_phase_signal ( uint32_t * out_rssi )

static

Signal phase: query AT+CSQ and parse + print the RSSI.

Parameters

[out] out_rssi Receives the parsed RSSI (or 99 if unparsed).

Returns: true iff the RSSI is a valid reading (modem_signal_valid).

Precondition: The driver was bound and out_rssi is non-NULL.

Postcondition: On query failure the function never returns.; *out_rssi holds the parsed RSSI; the banner prefix is emitted.

Since: 0.1.0

Definition at line 795 of file main.c.

References k_modem_banner_prefix, k_modem_capture_cap, k_modem_csq_unknown, k_ra8_ok, modem_emit_kv(), modem_fail(), modem_parse_first_uint(), modem_query(), and modem_signal_valid().

Referenced by main().

◆ modem_phase_sim()

bool modem_phase_sim ( void )

static

SIM phase: query AT+CPIN? and confirm READY.

Returns: true iff the SIM reported +CPIN: READY.

Return values

true	SIM is ready.
false	SIM not ready (query error path parks via modem_fail).

Precondition: The driver was bound.

Postcondition: On query failure the function never returns.; On success the return reflects the READY substring test.

Since: 0.1.0

Definition at line 773 of file main.c.

References k_modem_capture_cap, k_ra8_ok, modem_fail(), modem_line_contains(), and modem_query().

Referenced by main().

◆ modem_phase_sync()

void modem_phase_sync ( void )

static

Sync phase: probe (AT), disable echo (ATE0), numeric CME errors.

Any non-OK here parks via modem_fail (the modem is absent / dead).

Precondition: The driver was bound.

Postcondition: On return all three sync commands returned OK.; On any failure the function never returns.

Since: 0.1.0

Definition at line 746 of file main.c.

References k_ra8_ok, modem_cmd_ok(), and modem_fail().

Referenced by main().

◆ modem_query()

ra8_err_t modem_query	(	const char *	cmd,
		char *	buf,
		size_t	cap )

static

Send an AT query and capture its response payload.

Parameters

[in]	cmd	NUL-terminated AT command (no trailing CR).
[out]	buf	Capture buffer for the payload lines.
[in]	cap	Capacity of `buf`.

Returns: The ra8_modem_at_send_cmd_capture return code.

Precondition: The driver was bound by modem_bind.; buf is non-NULL and cap >= 1.

Postcondition: On success buf is NUL-terminated with the captured payload.; No app state is mutated here.

Since: 0.1.0

Definition at line 702 of file main.c.

References k_modem_cmd_timeout_ms, and ra8_modem_at_send_cmd_capture().

Referenced by modem_phase_attach(), modem_phase_signal(), and modem_phase_sim().

◆ modem_run_ok()

bool modem_run_ok	(	bool	sim_ready,
		bool	signal_ok,
		bool	registered,
		bool	attached,
		bool	cme_ok )

static

Overall run verdict: every probed condition must hold.

Parameters

[in]	sim_ready	SIM reported +CPIN: READY.
[in]	signal_ok	CSQ RSSI was a valid reading.
[in]	registered	+CREG status was home or roaming.
[in]	attached	CGATT reported attached.
[in]	cme_ok	The error-probe step returned the expected CME error.

Returns: true iff ALL five inputs are true.

Return values

true	Every condition held.
false	Any one condition failed.

Precondition: The five flags were derived from a completed AT run.; No shared state is read.

Postcondition: No state is mutated.; Return value depends solely on the five inputs.

Note: Pure function; thread-safe.

Since: 0.1.0

Definition at line 252 of file main.c.

Referenced by main().

◆ modem_rx_byte()

ra8_err_t modem_rx_byte	(	void *	ctx,
		uint8_t *	out_byte )

static

Definition at line 481 of file main.c.

References k_modem_uart_channel, and ra8_sci_getc_polling().

Referenced by modem_bind().

◆ modem_setup_or_halt()

void modem_setup_or_halt ( void )

static

Bring CGC + console (SCI8) + modem UART (SCI7) + LEDs up.

Precondition: Reset copied .data and zeroed .bss.

Postcondition: SCI8 console + SCI7 modem UART are live; LED1/LED2 are configured.; On any failure the function never returns (parks).

Since: 0.1.0

Definition at line 607 of file main.c.

References k_modem_baud, k_modem_console_baud, k_modem_uart_channel, k_ra8_board_led1, k_ra8_board_led2, k_ra8_ok, k_ra8_sci_data_8, k_ra8_sci_parity_none, k_ra8_sci_stop_1, modem_clocks_or_halt(), modem_panic_halt(), modem_pfs_or_halt(), ra8_board_led_init(), ra8_board_uart_console_init(), and ra8_sci_init().

Referenced by main().

◆ modem_signal_valid()

bool modem_signal_valid ( uint32_t rssi )

static

Is a CSQ RSSI reading a known, usable signal?

Two independent conditions: the reading must be a real measurement (not the 99 "unknown" sentinel) AND at least k_modem_csq_min_bars of strength. The two are genuinely independent – 99 (unknown) is above the strength floor, so either can fail alone – which is what makes the compound MC/DC-testable.

Parameters

[in] rssi A CSQ RSSI index parsed from +CSQ: <rssi>,<ber>.

Returns: true iff rssi is a real reading with usable strength.

Return values

true	`rssi` != 99 and `rssi` >= k_modem_csq_min_bars.
false	`rssi` == 99 (unknown) or `rssi` below the usable floor.

Precondition: rssi is the first field of a +CSQ response.; No shared state is read.

Postcondition: No state is mutated.; Return value depends solely on rssi.

Note: Pure function; thread-safe.

Since: 0.1.0

Definition at line 197 of file main.c.

References k_modem_csq_min_bars, and k_modem_csq_unknown.

Referenced by modem_phase_signal().

◆ modem_step_passed()

bool modem_step_passed	(	bool	is_cme_probe,
		ra8_err_t	err )

static

Did an AT step return the outcome the app expected?

Every step but the deliberate error probe expects k_ra8_ok. The error probe sends an unsupported command and EXPECTS the modem's +CME ERROR (which the driver surfaces as k_ra8_err_hw_error): for that step a plain OK would actually be a failure. This inverts the pass condition on the probe step, which is the interesting compound decision.

Parameters

[in]	is_cme_probe	true for the intentional unsupported-command step.
[in]	err	The ra8_modem_at return code for that step.

Returns: true iff err is the expected outcome for the step.

Return values

true	(probe and `err` == hw_error) or (non-probe and `err` == ok).
false	Otherwise.

Precondition: err came from a completed ra8_modem_at_send_cmd* call.; No shared state is read.

Postcondition: No state is mutated.; Return value depends solely on is_cme_probe and err.

Note: Pure function; thread-safe.

Since: 0.1.0

Definition at line 226 of file main.c.

References k_ra8_err_hw_error, and k_ra8_ok.

Referenced by modem_phase_error().

◆ modem_tx()

void modem_tx	(	const uint8_t *	bytes,
		uint32_t	len )

static

Emit a byte run on the J-Link OB VCOM console (SCI8).

Parameters

[in]	bytes	Byte array to transmit (non-NULL when `len` > 0).
[in]	len	Number of bytes.

Precondition: bytes is non-NULL when len > 0.; The console was initialised by modem_setup_or_halt.

Postcondition: All len bytes have been handed to SCI8.; No app state is mutated.

Since: 0.1.0

Definition at line 443 of file main.c.

References ra8_board_uart_console_write().

Referenced by main(), modem_emit_kv(), and modem_fail().

◆ modem_tx_byte()

ra8_err_t modem_tx_byte	(	void *	ctx,
		uint8_t	byte )

static

Definition at line 475 of file main.c.

References k_modem_uart_channel, and ra8_sci_putc_polling().

Referenced by modem_bind().

◆ modem_u32_to_dec()

uint32_t modem_u32_to_dec	(	uint32_t	value,
		uint8_t *	out )

static

Convert an unsigned 32-bit int into a decimal ASCII string.

Parameters

[in]	value	Integer to convert.
[out]	out	Destination buffer (>= k_modem_dec_cap bytes).

Returns: Number of bytes written (excluding any NUL).

Precondition: out is non-NULL and >= k_modem_dec_cap bytes.; The result never exceeds k_modem_dec_cap digits.

Postcondition: out holds the decimal digits, most-significant first.; The returned length is in [1, k_modem_dec_cap].

Note: Not thread-safe with a shared out buffer.

Since: 0.1.0

Definition at line 410 of file main.c.

References k_modem_dec_base, and k_modem_dec_cap.

Referenced by modem_emit_kv().

Variable Documentation

◆ k_modem_banner_prefix

const uint8_t k_modem_banner_prefix[] = "modem: rssi="

static

Definition at line 140 of file main.c.

Referenced by modem_phase_signal().

◆ k_modem_str_attach

const uint8_t k_modem_str_attach[] = " attach="

static

Definition at line 142 of file main.c.

Referenced by modem_phase_attach().

◆ k_modem_str_cme

const uint8_t k_modem_str_cme[] = " cme="

static

Definition at line 143 of file main.c.

Referenced by main().

◆ k_modem_str_fail

const uint8_t k_modem_str_fail[] = " FAIL\r\n"

static

Definition at line 147 of file main.c.

Referenced by main().

◆ k_modem_str_no

const uint8_t k_modem_str_no[] = "no"

static

Definition at line 145 of file main.c.

Referenced by main().

◆ k_modem_str_ok

const uint8_t k_modem_str_ok[] = "ok"

static

Definition at line 144 of file main.c.

Referenced by main().

◆ k_modem_str_pass

const uint8_t k_modem_str_pass[] = " PASS\r\n"

static

Definition at line 146 of file main.c.

Referenced by main().

◆ k_modem_str_reg

const uint8_t k_modem_str_reg[] = " reg="

static

Definition at line 141 of file main.c.

Referenced by modem_phase_registration().

◆ s_creg_seen

bool s_creg_seen

static

True once at least one +CREG line has been parsed.

Note: Written by modem_on_creg_urc.

Warning: Direct external modification is forbidden.

Since: 0.1.0

Definition at line 135 of file main.c.

Referenced by modem_on_creg_urc(), and modem_phase_registration().

◆ s_creg_stat

uint8_t s_creg_stat

static

Latest registration status parsed from a +CREG line.

Note: Written by modem_on_creg_urc (URC + solicited); read for the verdict.

Warning: Direct external modification is forbidden.

Since: 0.1.0

Definition at line 126 of file main.c.

Referenced by modem_on_creg_urc(), and modem_phase_registration().

Enumerations

Functions

Variables

Detailed Description

Enumeration Type Documentation

◆ modem_cap_t

◆ modem_cgatt_t

◆ modem_const_t

◆ modem_creg_stat_t

◆ modem_csq_t

◆ modem_timeout_t

Function Documentation

◆ main()

◆ modem_bind()

◆ modem_clocks_or_halt()

◆ modem_cmd_ok()

◆ modem_creg_registered()

◆ modem_emit_kv()

◆ modem_fail()

◆ modem_line_contains()

◆ modem_now_ms()

◆ modem_on_creg_urc()

◆ modem_panic_halt()

◆ modem_parse_first_uint()

◆ modem_parse_last_uint()

◆ modem_pfs_or_halt()

◆ modem_phase_attach()

◆ modem_phase_error()

◆ modem_phase_registration()

◆ modem_phase_signal()

◆ modem_phase_sim()

◆ modem_phase_sync()

◆ modem_query()

◆ modem_run_ok()

◆ modem_rx_byte()

◆ modem_setup_or_halt()

◆ modem_signal_valid()

◆ modem_step_passed()

◆ modem_tx()

◆ modem_tx_byte()

◆ modem_u32_to_dec()

Variable Documentation

◆ k_modem_banner_prefix

◆ k_modem_str_attach

◆ k_modem_str_cme

◆ k_modem_str_fail

◆ k_modem_str_no

◆ k_modem_str_ok

◆ k_modem_str_pass

◆ k_modem_str_reg

◆ s_creg_seen

◆ s_creg_stat