the clock function is not working in esb_ptx example for nRF52832

RE: the clock function is not working in esb_ptx example for nRF52832

Masoumeh — Mon, 14 Dec 2020 09:41:16 GMT

Finally it worked. As you said it was because of the Cap load of the crystal. they were off. Thanks for all the time that you spend for answering my questions.

RE: the clock function is not working in esb_ptx example for nRF52832

Einar Thorsrud — Tue, 08 Dec 2020 14:34:35 GMT

Hi,

[quote user="Masoumeh"]The problem now is that the RF part is not working. I am using the Chip antenna now. it is the 2450AT18B100. what factors may interfere in this part? does the cap load of the crystal matters?[/quote]

There are several factors that affect the RF performance. First of all, the antenna must be properly matched and tuned. This is the case also for a chip antenna. The load caps of the HF crystal also has a significant impact on the RF performance. If the load caps are off, the RF frequency will be off, and thus RF communication will not work.

RE: the clock function is not working in esb_ptx example for nRF52832

Masoumeh — Tue, 08 Dec 2020 10:55:09 GMT

Finally I was able to see the crystal working. The problem was because of the fact that the input and output pins of the inverter in nrf (XC1 , XC2) damaged during the soldering process or in any other situation, which is very odd since they should not be broken that easily. The problem now is that the RF part is not working. I am using the Chip antenna now. it is the 2450AT18B100. what factors may interfere in this part? does the cap load of the crystal matters?

RE: the clock function is not working in esb_ptx example for nRF52832

Einar Thorsrud — Mon, 30 Nov 2020 14:34:41 GMT

Hi,

The loop waits for the HFCLKSTARTED event, which has the following condition: "A HFCLKSTARTED event will be generated when the HFXO has started and its frequency is stable.". So we need to look more at your crystal circuitry.

One potential issue we have not discussed before is that C22 shard ground with DEC2 and DEC3. This could be enough to affect the clock. Can you try to connect C22 directly between pin 1 and 4 on the crystal?

RE: the clock function is not working in esb_ptx example for nRF52832

Masoumeh — Sat, 28 Nov 2020 17:54:29 GMT

Hi, now, crystal is oscillating with the NRF but the problem is that the nrf can not pass through the loop which indicate that the HFCLK is running, I mean the loop below:

void clocks_start( void )
{
    NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
    NRF_CLOCK->TASKS_HFCLKSTART = 1;

    while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);
}

what can cause this problem? the signal that I am seeing in the oscilloscope is:

I know that the probe may reduce its amplitude, but even without the probe it can not pass from the loop.

RE: the clock function is not working in esb_ptx example for nRF52832

ketiljo — Wed, 25 Nov 2020 11:11:34 GMT

All pins have ESD protection, so it you can't measure the diode to VDD or GND, the device is broken.

The input signal is too high, try with a ~300 mVpp signal instead. A too high signal won't break it as long as it's within rails but will clip or distort the signal.

Try reflow or resolder the crystal again.

RE: the clock function is not working in esb_ptx example for nRF52832

Masoumeh — Mon, 23 Nov 2020 16:45:36 GMT

Also I wanted to know if the inverter is working or not. so I gave a pulse to the input of the inverter (XC1) and monitor the output (XC2). I saw that the signal is inverted but the output signal is weakened. as you can see in the below. the yellow one is the input and the purple one is the output.

RE: the clock function is not working in esb_ptx example for nRF52832

Masoumeh — Mon, 23 Nov 2020 14:45:30 GMT

I really don't get that why the oscillator is not working. another question is that in the nrf XC1 pin, which is the input of the inverter, is there any ESD protection? as I tested I cannot find any in this pin, but in XC2 we have ESD protection.

RE: the clock function is not working in esb_ptx example for nRF52832

Einar Thorsrud — Mon, 23 Nov 2020 13:46:25 GMT

Hi,

There are mainly two example in the SDK that are intended for testing:

The Radio test example (for general radio testing)
Direct Test Mode (used for Bluetooth certification)

Regarding the antenna and ground that could be relevant for radio/antenna performance, but should not affect the clock. And certainly not so that the HFXO does not start (which seems to be the primary issue here).

RE: the clock function is not working in esb_ptx example for nRF52832

Masoumeh — Sun, 22 Nov 2020 18:14:51 GMT

Also I have another question. which example in the SDK can help me to put the nrf in test mode?

RE: the clock function is not working in esb_ptx example for nRF52832

Masoumeh — Sun, 22 Nov 2020 14:43:55 GMT

I did it, but nothing changed. I have a question. I have a PCB antenna on my board which I copied it from some manual. the thing is that a part of this antenna is connected to the ground by a via, as you can see below. do you think that it can make any problem for the ground? I used two kind of antenna on my board to check their quality and this part of circuit is not connected to the RF line, but it is connected to ground by via.

RE: the clock function is not working in esb_ptx example for nRF52832

Einar Thorsrud — Tue, 17 Nov 2020 15:38:37 GMT

Everything looks to be correctly oriented. But the soldering under the crystal looks a bit bad, particularly under the XC1 pad. Can you try solder another board and see if that works?

RE: the clock function is not working in esb_ptx example for nRF52832

Masoumeh — Tue, 17 Nov 2020 08:05:05 GMT

Hi, attached them.

RE: the clock function is not working in esb_ptx example for nRF52832

Einar Thorsrud — Mon, 16 Nov 2020 13:14:13 GMT

Hi,

Can you take a photo of your board showing how you have mounted the crystal?

RE: the clock function is not working in esb_ptx example for nRF52832

Masoumeh — Mon, 16 Nov 2020 10:32:53 GMT

Hi,

I bought the Q22FA12800025 crystal and soldered it on the circuit, but it's not working yet. I sent you my PCB, do you think can it be from the PCB? I will attach it here again.

devzone.nordicsemi.com/.../0676.PCB.PcbDoc

RE: the clock function is not working in esb_ptx example for nRF52832

Einar Thorsrud — Tue, 13 Oct 2020 14:47:12 GMT

Hi,

I see. You should get the crystal to oscillate using the nRF, provided you solder it the right way and have sensible load caps.

RE: the clock function is not working in esb_ptx example for nRF52832

Masoumeh — Tue, 13 Oct 2020 13:01:14 GMT

I checked my Crystal by an inverter and it's working as you see in the picture. is it possible that the inverter that i used is capable of working with the crystal but the nRF52832 isn't? my inverter is 74AC04DR.

RE: the clock function is not working in esb_ptx example for nRF52832

Einar Thorsrud — Mon, 12 Oct 2020 16:14:38 GMT

Hi,

In most cases, no. The radio is very sensible to phase noise, and a PLL based clock source will not be good enough, and that is what most signal generators use. You need a crystal based oscillator of some sort.

RE: the clock function is not working in esb_ptx example for nRF52832

Masoumeh — Mon, 12 Oct 2020 15:50:53 GMT

is it possible to make a clock by signal generator and test the nRF52832 by this clock? does it make any problem for nRF?

RE: the clock function is not working in esb_ptx example for nRF52832

Einar Thorsrud — Wed, 07 Oct 2020 08:24:10 GMT

You can use Q22FA12800025, which is used on the DK, or any other that matches the requirements in the electrical specifications for the HFXO. Please refer to this post for more.

RE: the clock function is not working in esb_ptx example for nRF52832

Masoumeh — Tue, 06 Oct 2020 19:31:08 GMT

Do you have any suggestion for crystal?

RE: the clock function is not working in esb_ptx example for nRF52832

Einar Thorsrud — Tue, 06 Oct 2020 12:35:20 GMT

Hi,

[quote user="Masoumeh"]you mean that the crystal cannot work for this IC?[/quote]

The problem is the stability and tolerance. Sp it may or may not work, and it could vary from device to device. This means that if you are lucky it could be good enough to play with, but it is for sure not suitable for mass production as you can never know if a device will work or not without testing it (and happen to be lucky and get one that performs better than expected).

RE: the clock function is not working in esb_ptx example for nRF52832

Masoumeh — Tue, 06 Oct 2020 09:43:17 GMT

I ordered the crystal due to the spec in below link.

https://www.mouser.com/ProductDetail/Kyocera-Electronic-Components/CX2016DB32000D0WZRC1?qs=mHG8nxlouK5LiZGb%2FcBxwg%3D%3D

you mean that the crystal cannot work for this IC?

RE: the clock function is not working in esb_ptx example for nRF52832

Einar Thorsrud — Tue, 06 Oct 2020 09:30:13 GMT

Hi,

There are several potential issues here:

Make sure the value of the load caps matches the CL value of the crystal: Ccap = CL *2 - 4 pF. 12 pF load caps, C19 and C22, is correct for a crystal with CL = 8 pF. If a different crystal is used, the load caps must be changes accordingly.
Make sure the crystal is soldered the correct way. Turning the crystal 90 degrees to make it easier to solder will not work.
The crystal you are using, CX2016DB32000D0WZRC1, is out of spec. The stability and tolerance is too high. The total needs be be +/-40 ppm or better.

RE: the clock function is not working in esb_ptx example for nRF52832

Masoumeh — Tue, 06 Oct 2020 08:54:54 GMT

This is my PCB layout. in the right part of it you can see the nRF52832 and its components. the schematic of the nordic is exactly like datasheet. I just remove the LFCLK crystal.

devzone.nordicsemi.com/.../PCB.PcbDoc