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Suspend Service - Graceful shutdown

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Suspend Service - Graceful shutdown


Below you can find information on the Suspend service, which enables a graceful shutdown of the FAT file-system, in case of a power failure.

1 Power failure and file-systems

During the device's life-time, power failure may occur. These failures threaten the reliability of the FAT file-system. The use of Windows CE's TFAT (Transaction-safe FAT) / ExFAT significally reduces the risk of a file-system corruption. However, no file system is 100% fail-safe. Power failure while file-system is actively writing, might rarely cause errors, even while using TFAT. Therefore, a graceful shutdown at power failure incident, when possible, is recommended. The suspend service requires 250ms to complete the File-system shutdown, while SOMs power consumption is 1.32Watt (400ma @3.3v)

2 Suspend service - Graceful shutdown. Usage guidelines

Suspend service is waiting for a falling-edge event of a specific GPIO, at a high-priority task. Once such event is triggered, the Suspend-service gracefully shuts-down the FAT file-system at the highest priority.

Suspend service is available from BSP version 1.3.6 and forth.

Usage Guidelines:

  • To enable the Suspend Service, please set:
set BSP_SSP=1

in VAR_OM35xx_P.bat

  • in FILES\platform.reg you may choose the appropriate GPIO which triggers the event:
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn\SSP]
   "Prefix"="SSP"
   "Dll"="sspdrv.dll"
   "Index"=dword:0
   "Order"=dword:40
   "GpioId"=dword:6D ;GPIO#109