Bogdan Lazarescu
This library allows any user to use their Mbed project with a transient energy source( e.g. windturbine, solar power).
This library allows any user to use their Mbed project with a transient energy source( e.g. windturbine, solar power). You can do this by simply import the "hibernus.h" header file, and call the "Hibernus()" method at the beginning of you main program. In case of a power loss the state of your programm will be saved to the nonvolatile memory and it will be resumed from the same point as soon as there is enough power for the board to run properly. If the power drops down, the internal capacitance of the system is used to save a snapshot of your program into the flash memory, and the board goes in a low power mode (sleep or deepsleep). In order to detect a power loss, the library uses an analog comparator which can be internal (eg Freescale KL 05Z has an internal comparator which can be used ), or external (on LPC11U24 there is no internal comparator) via a GPIO interrupt. For more details see the code comments and the attached example main.cpp file.
This library use "IAP" library, in order to write the required data to the flash nonvolatile memory.
The library can be easily adapted to work with other boards, from different manufactures, which have support for Mbed. In order to adapt this library and use it on your board, the write to flash methods have to be changed. Some changes listed below are required because of the platform dependent parameters of each board. All required changes have to be applied to the "config.h" and "config.cpp" files.
- The "erase_flags_memory()", "copyRamToFlash()", "restore_flags()", "setFlag()" and " isFlagSet()" methods have to be modified in order to use the right Flash IAP of your board.
- The wake up and hibernate interrupts have to be modified in order to be trigghered when the voltage drops down or rise. If you use an internal comparator, it should trigger and interrupt whenever the power drops(e.g see CMP0_IRQHandler() method writtend for KL05Z at https://developer.mbed.org/users/BogdanL/code/Hibernus-KL05Z/ ) . At that time a snapshot have to be saved and the board sent to sleep. Another interrupt have to be triggered when the power comes back(see "LLW_IRQHandler()" at https://developer.mbed.org/users/BogdanL/code/Hibernus-KL05Z ) . This have to wake up the board and resume de computation. In you use an external comparator two GPIO interrupts are used. One of them (for LPC11U24 see "FLEX_INT1_IRQHandler()" ) is used to save the snapshot when the power drops down, and the other one (for LPC11U24 see "FLEX_INT0_IRQHandler()" ) is used to wake up the board.
- For each board, the right Sleep mode have to be chosen. Also the interrups and the comparator have to be properly set, in order to be triggered as desired. For a good example see "configure_VR_gpio_interrupt()" and "configure_VH_gpio_interrupt()" that are used to set up the Restore and Hibernate interrupts on LPC11U24 board, that uses an external comparator.
- In the "config.h" file, the two arrays, "REG_Addresses_4B[]" and "REG_Addresses_4B[]" have to be populated with the addresses of the 1 Byte and 4Bytes peripheral registers that are used by your project. Different boards have different modules that use different peripheral registers. The addresses of the registers can be found in the Reference Manual of each board, and will be used in order to save and later restore the content of the registers. Also the number of used registers, "No_Of_4B_Peripheral_Reg", No_Of_1B_Peripheral_Reg, have to be updated with the correct number of used registers.
- At the top of "config.h" header file, specific board parameters have to be fixed: RAM start address(RAM_1_Address), Flash start address(FLASH_Start), RAM size(RAM_Size), Flash size(flash_Size) and the flash sector size(sector_Size).