Volume production: A reasonable on-off testing menthod

Hi Toradex Support team:
I would like to ask a quesiton about the production test which is On-Off test.
On-Off Test defination:
A Whole customer product( Toradex Module with customized carrier board or Toradex Carrier board, case, power supply), a Circle start from power on for a short period and then power off immediately(Power on period), then wait for another short period(Wait period) for power on again. the circle repeat for serveral thousand of time.
The purpose:
it will properly make sure the product will boot sucessful in next several years. The test orignal cames from notebook production test.
My question is for ARM base product. how to select the time interval make this test safe.
for example, one of customer set the power on period as 10 seconds booting(Power on period) and then power off immediately, wait for 3 seconds(Wait period) and start boot again. they use Colibri PXA320IT and WINCE6. it has been a stardard test before release their product. Normally a Hardware timer relay can be used for this test.

Nowadays,there is another customer, they use our Aplis TK1, ubuntu system, a fully boot need around 60s. so, do you have any suggestion about the power on period and wait period.

The Arm base product will have a difference boot phase. Eboot/uboot, release the image to RAM. OS start…, so, do you know set the power off in which period will have more risk for damage the flash/RAM. it will repeat for several thousand times.
pls advice!



Hi Li
There is no generic answer. The most critical moment to power-off the system is probably, when the system is in the middle of a write process (i.e. some data is still in the cache but not yet written back to flash).
If you want to stress-test the system for unexpected power-loss, you probalbly should choose the power-off time randomly spread over the whole boot time, while forcing write operations to the maximum.
If you want to simulate friendly shutdowns, you should let the application trigger a GPIO after it is ready, and use the signal as an indicator to toggle the power relay.