4DSP Support Forum
Products => FMC Products => FMC150 => Topic started by: xiaoqing2929 on June 11, 2014, 04:33 AM
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I have tried many different values to config CDCE72010's register, but i failed. I just want an external clock(119MHz) to be the ads62p49's sampling clock. After i config the CDCE72010, I do get a pair of 119MHz signal in out2_p and out2_n( which are to feed the ads[size=78%]62p49's sampling clock). But i don't think they are LVPECL signal , because out2_p and out2_n have the same wave, but their amplitude are different, out2_n's amplitude is 4 times out2_p's. [/size]
I found in the forum someone have the same problem(about how to config CDCE72010), and 4DSP's engineer's advise is to refer to the 'reference software application' . however after i download the 1GB-size 4FM.SDK file and setup on my computer, I am more confused about how to operator this application( i cannot find the CDCE72010's register setting)
Anyway, all i want to know are some points on configing the CDCE72010.( I have read the datasheet many times, some points are really not explained clearly）
1. when i use external clock, I use the CDCE72010's AUX as the feed of output divider. Should the AUX be congfiged as LVPECL or LVDS ?
2. How to config register8's 8.2 to 8.5 ( i think these bits are very importent,and their value is decided by the chip's [/size][size=78%][/size][size=78%][/size][size=78%] the FMC150 data manul oughts to tell us how to config them) [/size]
3. Should the output9 be disabled?
4.Do the PRI_REF and SEC_REF's setting not have any effect in case i use external clock.
Help me !
cecilia
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Dear Cecilia,
You can still get in touch with TI for question around the CDCE chip. The CDCE72010 register setting in the software application are found in the following module:
Fmc15xAPP\Libs\FMC15x\Impls\fmc15x_clocktree.cpp
The software application's main in main.cpp take an argument for clock mode. There are three clock modes: 0 = Internal clock with internal reference, 1 = External clock and 2= Internal Clock with external reference. The value passed as argument i converted to integer and placed in modeClock variable. modeClock is then passed to fmc15x_init() which will call fmc15x_clocktree_init().
There is also some important information in the FMC150 user manual on how to control the device.
I hope that helps!
Best Regards,
Arnaud
Arnaud
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Dear Arnaud,
Thanks for your reply. I found the CDCE72010's register setting in software application with your help. I finally observe the correct LVPECL signal(119MHZ) in out2_p and out2_n succesfully!
The CDCE72010's register setting is as follows(using external clock as the ADS62P49's sampling clock)
683C0310
68000021
83400002 (divider num: 1)
68000003
E9800004(divider num: 2)
68000005
68000006
83400017(divider num: 1)
68000018
68050CC9
05FC270A
0280044B
0000180C
cecilia
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This topic is being closed because the issue is considered as resolved by 4DSP. Feel free to create a new topic for any further inquiries.