Scripting & Automation

pcu-cli is built to be scripted. Data goes to stdout; prompts, warnings, and errors go to stderr; and every command sets a meaningful exit code. This page covers the flags and output formats you need for unattended use. For the full command list, see the Command Reference.

Output discipline

• stdout carries the data: the status table, timer values, channel states, and all JSON.
• stderr carries confirmation prompts, warnings, and error messages.

Because prompts and warnings never touch stdout, you can capture clean data with pcu-cli ... > out.txt while any prompt still appears on the terminal.

Flags

Flag	Description
--quiet	Bare values only, one per line. Also skips confirmation prompts.
--json	JSON output. Supported on status, ign, dio, and version.
--yes, -y	Skip write confirmation prompts.
--version, -V	Print version info and exit. Runs without elevation.
-h, --help, /?	Print command help and exit.

Notes:

• --quiet implies --yes: quiet writes never prompt.
• --json on its own still prompts before a write. Add --yes for unattended writes.
• --json and --quiet have no effect on driver; its output is always the text form.
• pcu-cli reads no environment variables and no configuration files. Everything is passed on the command line.

Caution

When input is redirected (a pipe, a here-string, or < file), pcu-cli treats confirmation prompts as auto-confirmed and proceeds with the write, even without --yes. This is deliberate so that piped scripts do not hang waiting on a prompt, but it means a redirected ign set or dio set writes to hardware without asking. Only redirect input into pcu-cli when you intend the write to go ahead.

JSON output

status, ign, dio, and version emit a single indented JSON object on stdout. Errors still go to stderr, and the exit code is unchanged, so a script can branch on either.

status --json on a CQ20:

{
  "platform": "In-CarPC CQ20",
  "cpu": "Intel Atom x6425E",
  "mcu_identity": "CQ20 MCU",
  "hardware_rev": "DTB-IGN-MCU VER:10",
  "firmware": 12,
  "ignition": {
    "mode": 1,
    "ign_on_delay_s": 6,
    "sw_on_delay_s": 4,
    "sw_off_delay_s": 300,
    "pw_off_delay_s": 120
  }
}

ign --json is the timer summary on its own:

{
  "mode": 1,
  "ign_on_delay_s": 6,
  "sw_on_delay_s": 4,
  "sw_off_delay_s": 300,
  "pw_off_delay_s": 120
}

A single ign get read is { timer, value }, with the value in seconds:

{
  "timer": "sw-off-delay",
  "value": 300
}

A write reports the requested value, the value read back, and whether they match:

{
  "timer": "sw-off-delay",
  "requested": 120,
  "actual": 120,
  "verified": true
}

Timer keys on a CQ40N

Every timer key carries the unit it is counted in as a suffix: _s for seconds, _m for minutes. On a CQ20 every timer is always in seconds, so the keys are always _s and the shapes above never change.

On a CQ40N four of the five timers follow the delay unit, so their key names change with it. The same machine reports ign_off_delay_m while the unit is minutes and ign_off_delay_s after pcu-cli ign unit seconds. Only ign_on_delay_s is fixed, because that timer is always in seconds.

Do not hard-code the suffix on a CQ40N

A script that looks up ign_off_delay_m by name silently finds nothing once the unit is switched to seconds. Match on the key prefix, or read pcu-cli ign unit first and build the key from it.

ign --json on a CQ40N with the unit on minutes:

{
  "ign_on_delay_s": 7,
  "ign_off_delay_m": 1,
  "pw_off_delay_m": 15,
  "ups_off_delay_m": 5,
  "ups_pw_off_delay_m": 2
}

There is no mode key: the CQ40N has no ignition mode setting, and fields that do not apply are omitted rather than set to null.

ign get and ign set gain a unit property on a timer counted in minutes. It is omitted entirely when the timer is in seconds, so the CQ20 shapes above are unchanged:

{
  "timer": "pw-off-delay",
  "value": 15,
  "unit": "m"
}

Reading and setting the delay unit

ign unit --json reports the current setting:

{
  "unit": "minutes"
}

Changing it mirrors the ign set shape, but the key is setting rather than timer, because the delay unit applies to the whole device rather than to one timer:

{
  "setting": "delay-unit",
  "requested": "seconds",
  "actual": "seconds",
  "verified": true
}

A write still prompts for confirmation unless you pass --yes. Remember that the stored timer values are not converted, so a script that changes the unit should re-read and re-write the timers it cares about.

dio --json on a CQ40 series reports each channel as a boolean (true = High for a channel, On for the ignition line):

{
  "platform": "In-CarPC CQ40 series",
  "inputs": {
    "di1": false,
    "di2": false
  },
  "outputs": {
    "do1": false,
    "do2": false
  },
  "ignition": true
}

A dio set write mirrors the ign set shape, with booleans:

{
  "channel": "do1",
  "requested": true,
  "actual": true,
  "verified": true
}

version --json is the full inventory record: build stamp, driver and module versions, and the supported-platform catalogue. Use it for fleet inventory without touching the hardware bus.

{
  "app": "pcu-cli",
  "version": "1.1.0",
  "git_commit": "a1b2c3d",
  "build_date": "2026-07-01 09:15:32 UTC",
  "build_config": "Release",
  "os": "Windows",
  "pawnio_version": "2.2.0",
  "pawnio_date": "2026-03-15",
  "smbus_module_date": "2025-05-05",
  "lpcio_version": "0.2.7",
  "lpcio_date": "2026-06-03",
  "platforms": [
    {
      "model": "CQ20",
      "description": "In-CarPC CQ20",
      "cpu": "Intel Atom x6425E",
      "cpu_codename": "Elkhart Lake",
      "bus": "PCH SMBus",
      "features": "Ignition timers",
      "tested_os": [
        "Windows 11 25H2 (x64)",
        "Ubuntu 24.04 LTS (x64)"
      ]
    },
    {
      "model": "CQ40",
      "description": "In-CarPC CQ40 series",
      "cpu": "Intel (CQ41/CQ43/CQ47)",
      "cpu_codename": "Haswell",
      "bus": "SuperIO GPIO ports",
      "features": "Digital I/O",
      "tested_os": [
        "Windows 10 22H2 (x64)"
      ]
    },
    {
      "model": "CQ40N",
      "description": "In-CarPC CQ40N series",
      "cpu": "Intel (CQ41N/CQ43N/CQ47N)",
      "cpu_codename": "Skylake",
      "bus": "PCH SMBus",
      "features": "Ignition timers",
      "tested_os": [
        "Ubuntu 24.04 LTS (x64)"
      ]
    }
  ],
  "validated_configs": [
    "Windows 11 25H2 (x64)  - CQ20",
    "Ubuntu 24.04 LTS (x64)  - CQ20",
    "Windows 10 22H2 (x64)  - CQ40",
    "Ubuntu 24.04 LTS (x64)  - CQ40N"
  ]
}

JSON field notes

• Fields that do not apply are omitted, not set to null. On a CQ40, status --json has no ignition block; on a CQ20 it has no inputs or outputs; on a CQ40N there is no mode. On Linux, version --json omits the pawnio_*, smbus_module_date, and lpcio_* fields.
• A platform that has not been validated on hardware yet carries no tested_os list and contributes nothing to validated_configs. Treat an absent tested_os as “not validated”, not as a parsing error. Every platform in this release has at least one entry, but a newly added model may not.
• tested_os lists only the operating systems, one entry per validated configuration. The matching BIOS and date are not in the JSON; see Supported Platforms for those.
• features reports only the capabilities pcu exposes as features. The CQ40N’s selectable delay unit is not one of them, so its features string is Ignition timers even though ign unit works there.
• Boolean channel values are true for High (inputs and outputs) and true for On (the ignition line).
• On a write, the exit code mirrors the verified field: 0 when the readback matches, 1 when it does not. A script can check either.
• git_commit, build_date, and build_config in version --json are stamped at build time and will differ from the example above.

Quiet mode

--quiet prints just the value, with no labels or headers, one per line. It is the simplest form to parse and it never prompts. Reads:

$ pcu-cli ign get sw-off-delay --quiet
300

$ pcu-cli dio get di1 --quiet
0

Writes print the value read back, and still set the exit code from the readback:

$ pcu-cli dio set do1 1 --quiet
1

Examples

Assert a digital output at boot. On Linux, run this from a systemd unit or an @reboot cron job:

pcu-cli dio set do1 1 --yes

On Windows, run the same command from a Task Scheduler task set to trigger “At startup”:

pcu-cli.exe dio set do1 1 --yes

Collect a fleet inventory without touching the hardware bus:

pcu-cli version --json > inventory.json

Change the shutdown delay across a fleet and fail loudly if the write did not verify:

pcu-cli ign set sw-off-delay 120 --yes --quiet
if ($LASTEXITCODE -ne 0) { Write-Error "write not verified" }

Extract a single value with jq:

pcu-cli ign get sw-off-delay --json | jq '.value'

Cancelling

pcu-cli handles Ctrl+C gracefully: an in-flight bus transfer is allowed to finish and the transport is cleaned up before the tool exits, so a cancel never leaves a transfer half-done.

Thread and process safety

pcu accesses the hardware bus directly. To avoid clashing with other low-level tools, every transfer is serialized on the standard system-wide bus mutexes also used by tools like HWiNFO (Access_SMBUS.HTP.Method for SMBus, Access_ISABUS.HTP.Method for SuperIO port I/O). Each access waits up to 5 seconds for the bus, then fails cleanly.