Real Time clock reset values of Coldfire V2 and V3 processors

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Real Time clock reset values of Coldfire V2 and V3 processors

Contributor I

I am right now working with processors MCF 52235,52259 and 5329 and codewarrior as my IDE.I want to know what are the deafult or reset values for the real time clock registers. In the manual it has given as some arbitary value and with provided backup the RTC continues working even the power is off.                                 But when I tried resetting it all the values are turning to zero. By testing the power on rest with back up to the values are starting form the . Is there any idea.                                                               Can anyone help me with some info to help me test the power on reset for the RTC and verify that the RTC runs continously for the MCF 52235EVB which is not having any battery back up.                         Thanks for your time                                                                                                                                                                                                                                                                                                                                                                                                                                                                Latha

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2 Replies

Contributor I

A little late, but did you ever figure this RTC reset thing out?  I can't put my board in low power mode, so can't use that other option below.

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Contributor III

Hello Latha,


I had the same problem in past, I solved in this manner:

-) when the power supply switch off i have a battery that mantains the power only on the 3V3 (52235 and some buffers...);

-) the controller goes in the low power mode (where the RTC runs);

-) to exit from low power mode I use the interrupt of EPORT with the normal power supply; in the interrupt routine the Software copies the values of RTC registers in RAM:


 backup_day    =  MCF_RTC_DAYS;


-) in the initial routines, before the RAM inizialization, the software restore the values from RAM to RTC registers:


MCF_RTC_HOURMIN = ((backup_HHMMSS >> 16) & 0x1F3F);
 MCF_RTC_DAYS    = (backup_day & 0x0000FFFF);
 MCF_RTC_SECONDS = (backup_HHMMSS & 0x003F);




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