Hi,
I'm trying to implement low power modes on KL05 frdm board and measure the current consumption in different modes. Reffering to the schematics, I found out that MCU VDD is connected to P3V3_MCU which is coming from the jumper J4 which is DNP. But a 0 ohm R27 is in parallel to J4. I removed the R27 and soldered a jumper at J4 for putting a multimeter.
But then , what I noticed is MCU is still getting power . I checked the voltage on J4,2 [without putting the jumper], I'm seeing 1.8V. I'm confused from where the voltage is leaking.
Has anybody faced a similar issue? or am i missing something here?
P S : The resistance accross the jumper is 600k ohm
Thanks
Hi
There are a number of connections between the KL05 and the Open-SDA interface.
Very probably the you are measuring a voltage derived from there.
Regards
Mark
Hi Mark,
I'm reffering to FRDM-KL05 schematics. J4.2 is connected to P3v3_MCU which is connected to VDD of MCU. There is no connection between J4.1 and J4.2 . R27 is also removed. So if checked, we can see that MCU VDD is not connected to any pin now. I want to connect the multimeter in ammeter mode between J4.1 and J4.2. But without connecting the MCU is working but at a lower VDD of 1.9V This I'm measuring at J4.2 not anywhere else. I'm suspecting there is a leakage from somewhere to the VDD of MCU.
But can't make out.
Thanks,
Hi, Pramod
This issue is caused by K20 in SWD still communicates with KL05. So you detect the P3v3_MCU still has voltage value. Hope my reply can resolve your confuse.
Best Regards
Paul
Hi Zhe,
Thanks for the reply
Do you mean that since K20 is communicating, I get a voltage on VDD of the MCU?
If that is the case, how do you measure current consumption in various power modes?
Thanks,
HI
When the KL05 is not powered the voltages from the K20 are probably measurable since teh KL05 is not operatimng in a "defined state". This however probably doesn't cause any difficulties when the KL05 is powered normally and in a low power mode since then also the connection pins are defined and so there will be no such "leakage".
Regards
Mark
Thanks Mark,
I just measured the voltage. Since I made out that the MCU is not fully powered off, I didn't continue my experiment on KL05. Shifted to FRDM-KL25. Once, I finish that, I'll start on KL05.
But, FYI, The MCU is fully powered off when I disconnect the cut trace between jumper pins J4 of FRDM-KL25 unlike on FRDM-KL05 while both use K20 for openSDA
Thank you very much for your replies.