DA14695-00HQDEVKT-U kit and operating from 3.3V LDO (U2), J3 (pin1-2) does not seem to work

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mtailor
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DA14695-00HQDEVKT-U kit and operating from 3.3V LDO (U2), J3 (pin1-2) does not seem to work

Hi

I have two DA14695-00HQDEVKT-U kits and have loaded the WiRa ranging sample app from the WiRa SDK.
I do not have mikrobus displays but that is ok as I have defined that out from the builds.

I have the two devices connected to terminal emulators and I can see the outputs on power up.

When I have the default power setting :- 5V from VBUS J2:pin2-3  I can see the initiator connect to the responder and I see the distance being shown.

Wonderful.

That is all tethered to my PC.

So I thought let me now power the responder via J3:pin1-2 so that there is power on the VBAT pin of rh 14695 and obviously 0v on VBUS because there is no jumper on J2.

I was expecting to see the initiator to connect to the responder and show me some range readings -- did not work.
(I stress, the initiator just shows 'peripheral device not found')

Which means if I were to power the responder from a battery it is not going to work. Therefore I cannot perform any range test in open space outside over a longer range than just the 1.5m I can do on my desk.

I have not modified the firmware to operate 'in battery mode' as I see no documentation that I need to do that.

Is it the case that the logger in the responder is blocking because the uart buffer is full?

Look forward to hearing from someone.

Thank you.

 

 

 

Device: 
mtailor
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More on this.

More on this.
I have undefined CONFIG_RETARGET in the responder and and if power from VBUS it works (though to logs to terminal emulator as expected)

If I then move the jumper J3:pin1-2 then the initiator just reports 'peripheral device not found'

I will be most grateful for a detailed explanation of how to get my WiRa ranging to work so that
(1) Initiator is plugged into my laptop and will log the range data as I can currently see
(2) Responder is powered from either J3:pin1-2  and plugged into a phone usb power bank
(3) Then finally, it working with responder connected to a 3.3v battery and J3:pin2-3

Look forward to heraing from you.

 

mtailor
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More on this.

More on this.
With the jumper on J3:pin1-2 and when I plug it into my PC it all works.
If I unplug and then plug into a wall usb charger, it does not.

Smoking gun could be reset line from segger chip to the 14695.

Thoughts?

mtailor
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And I can confirm that when

And I can confirm that when powered from usb charger pin 2 on J3 is 3.3V confirming that VBAT has power but I VBUS has 0V however VBUS_OUT (As per figur 5 in UM-B-103 is obviously 5v too).

Hence only difference between plugging into wall charger and a laptop is that the segger chip and USB hub is powered and being driven by the PC.
 

mtailor
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More feedback.

More feedback.

With the device plugged into a PC the segger chip is being driven and RSTn line (Which is RESETn of 16495) is at 1.08V

With the device powered from wall charger the RSTn is at 0.42v

I think there is a problem with the reset line and perhaps needs a stronger pullup to ensure that RESETn is sitting near the power supply rail for the chip.

 

mtailor
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The datasheet (Table 9) PAD

The datasheet (Table 9) PAD_RESET, the HIGH level shall be a minimum of 0.7*1.2v= 0.84 and for low the max should be 0.3*1.2=0.36

I am measuring 0.42 so that is higher than 0.36 so it RESETn does not look like the smoking gun

 

mtailor
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After a circuit hack I can

After a circuit hack I can get it to work.
I shorted T_RESET which is on the other end of D9 to 3.3v and it fires up and I can see measurements at the initiator end.

So I replaced that short with a 3K3 pullup resistor so that T_RESET is high when the segger chip is not being driven by the PC and that works too as per the attached photo in the pdf.

 

PM_Dialog
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Hi mtailor,

Hi mtailor,

Thanks for your questions and for your findings. So. If I understood correctly, the problem exists if the DA14695 USB Kit is power through a battery. According to the user manual, you can supply 3.6 V to 4.3 V to VBAT pin, from external LiPo battery (connected to J5 header), when jumper placed to J3 (pin 2-3). Please see section 5.19 Power Selection Headers in the user manual in order to check how the battery should be connected and how the jumper’s configuration should be. Please also check Note 1 in the current section. Could you please indicate if you have used this configuration?  

Thanks, PM_Dialog

mtailor
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Hi

Hi

Thank you for coming back to me.

Now that you mention it, I did not use a battery to power the board.

However, I connected a phone battery pack to the USB connector J1 so that through the LDO (U2) I get 3.3v which is fed to VBAT via J3 (and also ensured there was no jumper on J2). I did that as it was easier to connect a phone battery pack to the USB connector.

Hence according to Figure 5 in UM-B-103, I was feeding VLDO into VBAT and that requires the pullup resistor.

I have not fed 3.6 to 4.3v to VBAT simply because 2 AA( or AAA) batteries gives me 3.0v and 3 AA (or AAA) batteries give me 4.5v and both 3.0v and 4.5v are outside the spec you and the user guide UM-B-103 mentions.

Can you please describe what type of battery you have used to get between 3.6 and 4.3v?  That is an unusual range.
Actually given I can make it work by feeding 3.3v via VLDO and it works, surely the VBAT spec should not be 3.6 and upwards because 3.3 clearly works.

Also please note that on page 63 of the DA1469x datasheet (CFR0011-120-00) you have VBAT1=VBAT2=3.0v. 
I genuinely thing that there is a typo in UM-B-103 and VBAT range should not be stated as 3.6v to 4.3v, but say either 1.6v or 2.6v to 4.3v 

Thank you

Look forward to hearing from you.

 

 

 

PM_Dialog
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Hi mtailor,

Hi mtailor,

My apologies for my late response. To be honest, I am little bit confused - could you please clarify what is the issue with the DK?

In general you can use USB (5 V), LDO (3.3 V), or external battery as a power source. You can use 3.6 V to 4.3 V from external LiPo battery (optional).

Thanks for your indication – I’ll evaluate this. Feedback would be more than welcome,

Thanks, PM_Dialog

PM_Dialog
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Hi mtailor,

Hi mtailor,

Since you are using the DA14695-00HQDEVKT-U, you should do the following HW modifications :

  1. If the DA14695 USB DK is to be connected to a power adapter or power bank, please remove D9, the tiny diode near K2.
  2. In case of DA14695 PRO mother board and USB DK board, sockets should be addedto J15 and J16 for OLED C Click Display to be clicked on.

 

Both HW modifications have already been applied in-house for all delivered DA14695 Wireless Ranging DKs.  Please see section 4.1 in the user guide.

Thanks, PM_Dialog