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Driver Page

The Driver page manages PawnIO, the kernel driver pcu uses to reach the hardware on Windows. It is a Windows-only page; on Linux it is greyed out, because hardware access goes through the kernel i2c-dev module instead (set up during Install on Linux).

As the page puts it: on Windows, pcu talks to the vehicle PC’s hardware through PawnIO, a small signed kernel driver. Windows blocks normal programs from touching the low-level hardware bus directly, so without this driver pcu cannot read or change ignition timers or digital I/O. It only needs to be installed once.

The pcu Driver page on Windows: the PawnIO driver status card, the manual installation options, and the bundled modules.

The “PawnIO Driver” card shows the current state:

  • Installed - pcu can reach the hardware.
  • Not installed - install it with the “Install PawnIO” button.
  • Reboot required - a reboot is pending to finish an install or uninstall.

Use “Refresh” to re-check the status.

  1. Select “Install PawnIO”.
  2. Accept the UAC prompt. PawnIO installs elevated and silently.
  3. pcu reports the result:
    • “PawnIO driver installed successfully.” - ready to use; pcu reconnects automatically.
    • “PawnIO driver installed. Reboot to complete installation.” - reboot, then reconnect.
    • “Installation cancelled. UAC prompt was declined.” - the elevation prompt was dismissed; try again and accept it.
    • “Installation failed. Try installing manually: winget install namazso.PawnIO” - see Manual installation below.

Select “Uninstall” and accept the UAC prompt. pcu shows “PawnIO driver uninstalled. Reboot to complete removal.” An uninstall always needs a reboot: the driver stays loaded in memory until then.

If the embedded installer fails, install PawnIO with winget (the page has a “Copy” button for the command):

Terminal window
$ winget install namazso.PawnIO

The CLI companion can also install it: run pcu-cli.exe as Administrator and it prompts to install the driver.

PawnIO loads signed Pawn VM modules to reach each platform’s hardware. The page lists both:

ModulePlatformPurpose
SmbusI801CQ20Auto-detects the on-board SMBus controller and reads/writes the MCU.
LpcIOCQ40 seriesGates raw port I/O to the SuperIO GPIO ports for digital I/O.

The bundled PawnIO version is shown on the card (currently v2.2.0). The modules are open source (LGPL-2.1); PawnIO itself is GPL-2.0.

If PawnIO will not install, or the hardware will not connect on Windows, see Windows Issues. To install pcu itself, see Install on Windows.