Hi All,
I've been building and testing for some time and am having difficulty with the PLL stage. When I program test_pll1() I am seeing a 5Hz wave on pin 10, where the documentation indicates I should be seeing 1Hz. The crystal is being driven correctly and the regulator is working. Any thoughts?
Attempting to tune a program generates the "RF VCO range is too low!" message, which would suggest that my PLL isn't functioning.
Cheers,
John
PLL Help
Moderators: adafruit_support_bill, adafruit
Please be positive and constructive with your questions and comments.
- grapeape
- Posts: 3
- Joined: Sun Jun 03, 2007 7:50 am
Re: PLL Help
Can anyone think of further tests to isolate the problem? I'm really quite lost at this point.
-
- Posts: 7
- Joined: Wed Jun 10, 2009 6:56 pm
Re: PLL Help
On the laydada webpage follow the Wiki link and look at the "Make" link, and then the PLL. You will see a notation that the frequency will be 5 not 1.
http://ladyada.net/wiki/wavebubble/pll
PLL Notes
when running the test_pll1 code. the rc1a firmware will set Ftest(pin 10) to 5hz (not 1hz as per the pll docs).
http://ladyada.net/wiki/wavebubble/pll
PLL Notes
when running the test_pll1 code. the rc1a firmware will set Ftest(pin 10) to 5hz (not 1hz as per the pll docs).
- grapeape
- Posts: 3
- Joined: Sun Jun 03, 2007 7:50 am
Re: PLL Help
Thanks Buggy. Not sure how I missed that note.
Is there a good reference around for debugging the PLL stage? I've been stuck here for quite a while. While the PLL section of the Make pages describes the tests to verify functionality along the way, it doesn't offer much help when one of the tests fails.
Is there a good reference around for debugging the PLL stage? I've been stuck here for quite a while. While the PLL section of the Make pages describes the tests to verify functionality along the way, it doesn't offer much help when one of the tests fails.
-
- Posts: 45
- Joined: Mon Dec 01, 2008 1:16 pm
Re: PLL Help
Did you get the other PLL test programs working? Im having problems with those, when I probe the middle of the two resistors for each stage as directed. Im not getting the switch over between around 0V and 2.1V
- c.b.
- Posts: 15
- Joined: Thu Oct 15, 2009 3:39 pm
Re: PLL Help
Hi Bandit,
I had problems, too, at that stage. I had forgotten to solder the resistor that connects the VCO's outputs to the PLL chip. Some HF went to the PLL chip through the air or I don't know how, anyway sometimes the PLL output flipped and sometimes not.
I had problems, too, at that stage. I had forgotten to solder the resistor that connects the VCO's outputs to the PLL chip. Some HF went to the PLL chip through the air or I don't know how, anyway sometimes the PLL output flipped and sometimes not.
-
- Posts: 45
- Joined: Mon Dec 01, 2008 1:16 pm
Re: PLL Help
I thought that might be the case so I placed some copper tape over the gap in the track. I would have thought some of the signal would be coupled throught both the air and the FR4 substrate, moreso through the substrate. I'll try putting the resistors on. Thanks.
Please be positive and constructive with your questions and comments.