关于AD9910低温下加电异常技术咨询
(Help needed regarding the fault of AD9910 at power-on in low temperature condition)
现象描述：低温下（-40℃~0℃）AD9910反复加电30次左右出现一次故障,无输出信号。AD9910仅使用分频功能，参考为480M单音信号,输出为26~30M单音信号。
(Fault description: AD9910 is used for frequency-dividing, with reference input of 480MHz, and output of 26~30MHz single tone signal. There is one fault ( with no output signal) out of 30 times at time of power-on in low temperature（-40℃~0℃） )
使用通用SPI控制发数,SCLK,SDIO和I/O_UPDAT时序如下:
Data was sent by general SPI interface, and the timing sequence of SCLK,SDIO Vs. I/O_UPDAT is as follows:
红色是SCLK，黄色是SDIO，绿色是I/O_UPDAT。
red-SCLK, yellow-SDIO, green- I/O_UPDAT
上图展开
观测SCLK与I/O_UPDAT交汇点。
watching the intersection of SCLK and I/O_UPDAT
咨询1：请问SCLK，SDIO与I/O_UPDAT如上图配置是否存在问题？
question 1: Is the parameter setting-up of SCLK，SDIO Vs. I/O_UPDAT is correct as being shown above
将SCLK和I/O_UPDAT时序改为如下后低温未出现故障现象。
when the timing sequence was changed as being shown followed, there was no fault at time of power-on in low temperature.
黄色为SCLK,绿色为I/O_UPDAT。
yellow--SCLK, green--I/O_UPDAT
将I/O_UPDAT在时钟完成2个周期后在置高
Once the I/O_UPDAT was set to high after 2 periods of SCLK, there was no fault at time of power-on in low temperature. our second question was: is there a delay required for I/O_UPDAT regarding SCLK signal? if yes, how to set up the time delay?
咨询2：更改时序后未出现故障，是否因为I/O_UPDAT与SCLK之间要求有延时，请问延时如何控制?
