LPC1768 Deep Sleep Counters work?

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LPC1768 Deep Sleep Counters work?

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lpcware
NXP Employee
NXP Employee
Content originally posted in LPCWare by kiryat8 on Sun Feb 23 06:18:47 MST 2014
In the low power AN10915 pdf it says "When the chip enters the Deep Sleep mode, the main oscillator is powered down, and nearly all clocks are stopped."
I need to use two internal timers as counters that will still count when in Deep-sleep mode.
Is this possible?
I could not get it to work.
The counters do work in regular sleep mode.
I leave the power active in the timers in both modes and just replace CLKPWR_Sleep(); with CLKPWR_DeepSleep(); and the other way around.

I understand that the internal oscillator remains running so I do not see why they do not count 1 count a second.

Any help would be appreciated.

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lpcware
NXP Employee
NXP Employee
Content originally posted in LPCWare by kiryat8 on Tue Feb 25 02:50:10 MST 2014
Before going into low power mode (deep sleep or normal sleep) I made the system clock source from the internal oscillator. I also tried changing the source to the RTC before sleeping.
In both cases the counter does not count external pulses when in deep sleep mode.
I am using two timers in counter mode with external triggers.
GPIO and both timers power are left on.
Thanks
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lpcware
NXP Employee
NXP Employee
Content originally posted in LPCWare by wmues on Mon Feb 24 08:15:19 MST 2014
Hmmm... maybe you can use the RTC to implement your counters?
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lpcware
NXP Employee
NXP Employee
Content originally posted in LPCWare by kiryat8 on Mon Feb 24 04:22:02 MST 2014
Thanks for your response but I have already read that section and it is exactly the same as the application note. "When the chip enters the Deep Sleep mode, the main oscillator is powered down, nearly all clocks are stopped, " is a statement I would not expect when working with a micro controller. I am used to knowing exactly what is running and what is not.
Does this mean that the pclk is not routed when in deep sleep mode?
Does the timer/counter use and really need the pclk in counter mode?
I can not find enough information in the pdfs.
I expected the counter to be able to count in deep sleep mode but maybe it is not completely static.
If the counter can run in deep sleep mode, I would like to continue and find my problem.
If not I will have to have external hardware or live with sleep mode.
Thank you



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lpcware
NXP Employee
NXP Employee
Content originally posted in LPCWare by cfb on Mon Feb 24 03:24:38 MST 2014
Read Section 4.8.2 "Deep Sleep Mode" in the LPC176x/5x User manual (UM10360). That should give you all the information you need.
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