Power (Power Management)

LibXR::PowerManager provides a unified interface for power management, suitable for implementing system reset, shutdown, or entering low-power modes. It is intended for implementation by platform or power control drivers.

Interface Definition

class PowerManager {
public:
  PowerManager() = default;
  virtual ~PowerManager() = default;

  // System reset operation (to be implemented by subclass)
  virtual void Reset() = 0;

  // System shutdown operation (to be implemented by subclass)
  virtual void Shutdown() = 0;

  // Jump to bootloader (falls back to Reset by default)
  virtual void JumpToBootloader() { Reset(); }

  // Register the power command in the RamFS root
  void RegisterCommand(RamFS& ramfs);

  // Read the pin once and enter the bootloader when it reads level
  void CheckBootloaderPin(GPIO& pin, bool level);
};

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Usage Notes

• Reset() can be used to perform a soft reset, restart the system, etc.;
• Shutdown() is used for power-off, entering sleep, or other low-power control;
• JumpToBootloader() falls back to Reset() by default, and platform implementations may replace it with a real bootloader jump;
• RegisterCommand(ramfs) registers the power command in the RamFS root (see In-Memory File System): in the terminal, power reset, power shutdown and power bootloader call the three methods above, while a missing or unknown argument prints the usage and returns -1. The command file is allocated on the first registration and is not freed afterwards, so one object is registered once;
• CheckBootloaderPin(pin, level) reads the pin once and calls JumpToBootloader() when it reads level, otherwise it returns; called once early during initialization, it enters the bootloader when the key on that pin is held through a reset, while the pin stays with the application at run time. The input direction and pull of the pin come from the project configuration and are left unchanged; a floating pin may trigger by accident;
• Can be applied in scenarios such as power button handling, remote commands, low battery strategies, etc.;
• The specific behavior is implemented by the platform, while the interface remains consistent to facilitate portability and abstraction.

Platform Implementations

In the MSPM0 MSPM0PowerManager, Reset() triggers the boot configuration routine, resets most of the core logic and power-cycles the SRAM, so the device restarts from Flash like a fresh power-up; Shutdown() enters the SHUTDOWN mode, woken up by NRST, SWD activity or a wake-up capable IO, and leaving SHUTDOWN triggers a BOR, so waking up is equivalent to a reset; JumpToBootloader() resets into the ROM BSL and, following the SDK example, clears the SRAM data and ECC codes before the reset to work around BSL_ERR_01. The MSPM0 ROM BSL runs over the serial port, so firmware can be flashed over that port after power bootloader.

In the HPM HPMPowerManager, Reset() enables the PPOR software reset source and then issues the reset; Shutdown() sets the turn-off counter and waits for the power down on SoCs with a PDGO, woken up by the RESETN pin, and falls back to disabling interrupts and executing WFI on SoCs without one; JumpToBootloader() disables the interrupts and calls the ROM API to enter the ROM ISP, with the peripheral auto-detected by the ROM; the call does not return normally, and a return resets the device. The ROM ISP over USB did not enumerate on the HPM5301 and HPM5361.

Notes

• PowerManager exposes three platform calls, Reset(), Shutdown() and JumpToBootloader(), and two general calls implemented by the base class, RegisterCommand() and CheckBootloaderPin().
• State queries, event callbacks, and low-power levels are left to concrete platform implementations or upper-layer code.