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Linux/AM3352: AM335x RTC Kick Register Write Issue in U-Boot

Part Number: AM3352

Tool/software: Linux

Hello,

We have a new custom board but can not bring up it(blank screen on debug console). After detail check using JTag, we found CPU will hang 

in  rtc32k_unlock() function(below figure) which located in <u-boot>/\arch\arm\cpu\armv7\am33xx\board.c.

Value of RTC_KICK0R_WE and RTC_KICK1R_WE are  0x83E7 0B13 and 0x95A4F1E0( match the values described in TRM 20.3.5.23,

since we do not modify original u-boot code)

 

If we remove rtc32k_enable() which calls  rtc32k_unlock(), u-boot could continue execute and print characters on debug console.

But we do not want to remove RTC since u-boot uses many time related functions.  

CPU is AM3352BZCZA100 and Processor SDK is 2.00.02.11.

Any suggestion is appreciated. Thanks.