lpc1768 adc power down

[lpcware]

Content originally posted in LPCWare by unknownobj on Mon Jun 06 02:03:06 MST 2016
hi, all

i am working on lpc1768 adc now, and the code to do the polling of adc works.
and then i want to use the power down of adc to minimize  the current,
so i set the PDN bit(ADC_PowerDownCmd)  before the adc function and clear it after adc.
i fount that the ADC_ChannelGetStatus function returns zero after ADC_StartCmd.

why?  how can i let adc go to power down mode and repower it before adc function?

any help is appreciated.

[kerryzhou · Accepted solution]

Hi Customer,

     Before you clear PDN to 0, please also clear LPC_AD0CR[START]=000.

   This is very important.

Please check this point, and try again.

Have a great day,

Kerry

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[billbrown]

Thank you so much Kerry,

That fixed the problem.  

I would press the correct answer button if I could find one.

Best regards

Bill

[billbrown]

I have a similar problem using a LPC-4078.  The ADC runs fine until I go into, and then come out of power down mode.

To maximize power saving, I shut off the PDN bit in the CR register prior to turning off the clocks as the users manual suggests.  But when I wake up and reverse that process, (turn on clocks in PCONP register and then turn on PDN bit in CR register) I no longer get conversion complete on the ADC.  

Any thoughts?

[kerryzhou]

Hi Bill,

     The same as LPC1769,  please check ADC control register START bit, please set it to no start(0x0) when you clearing PDN to 0.

  Please try it on your side.

If you still have question, please contact me!

Please check this point, and try again.

Have a great day,

Kerry

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[lpcware]

bump

[lpcware]

Content originally posted in LPCWare by unknownobj on Sun Jun 12 18:09:51 MST 2016
anyone help