Mehmet Fide

LC60: Exiting stop3 and then immediately writting flash

Discussion created by Mehmet Fide on Apr 5, 2008
Latest reply on Apr 5, 2008 by bigmac
Hi,
 
You know, to write to flash area, you have to set up FCDIV register once so that flash clock is in range 150-200kHz.
 
My bus frequency is 6.291456MHz in FEE mode, so I set divider as 35. (flash clock is 174.6KHz that is middle of the range)
 
For my application, the mcu enters to stop3 mode for a long time (a day), and then as soon as it wakes up, try to write some data to its flash area. As I know, mcu wakes at SCM mode to obtain fast wake-up time. it switch FEE mode automatically for a while later.
 
- How long time does it take mcu to switch FEE mode from SCM after waking-up?
- Should I wait for MCU to enter FEE mode before writting flash area?
- How does SCM frequency vary over temperature? There is a chart in the datasheet for trimmed 243kHz but, not for open loop DCO.
- If I try writting to flash area with open loop DCO after stop3, is it possible to violate 150kHz-200kHz range?
 
Regards,
BP.


Message Edited by BasePointer on 2008-04-05 06:19 PM

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