am3358 RTC hardware problem

No, there is no hardware bug in the  AM3358BZCZA100. Try to check inside the function to see where your code hangs. Where did you download the u-boot source from? Is it the one that comes with the SDK 6.0?

yes,the uboot comes from ti sdk6.0,and the version is u-boot-2013.01.01-psp06.00.00.00,

i upload the design file, there seems no error on the RTC .

6064.am335x_0325.pdf

so,what can i do?

Schematic seems correct. Have you checked what time it takes for the 32k oscillator to ramp up?

i use uboot + vxworks on my am335x board. 

if i i comment  rtc32k_enable() ,the uboot can work.after vxworks work,i can  read and write RTC register(BASE ADDR = 0x44e3e000) and the 32.768khz crystal oscillator can work.

if i open the   rtc32k_enable() ,the 32.768khz crystal oscillator can't work. i can't detect a 32.768khz  clock in the pin of 32.768khz crystal oscillator, then the uboot can't work and the debug terminal can't print anything.

so the hardware seems to OK,but i don;t know why the  crystal oscillator can't  work during the period of uboot?

thanks for your help

I can't comment on vxworks. This is a 3-rd party product and it's not supported by TI.

i have try linux kernel,the troble is the same as vxworks. 

so i think the troble is in uboot and my board.

i have welded a pull-up resistor on the pin EXT_WAKEUP,hower the trobule is all the same

i am puzzled.

You will have to check what happens inside the rtc32k_enable() function, that causes the processor to hang. However I'm not a SW expert and cannot help on this.