CC1352R: New custom board bring-up issue

My target chip is CC1352R, Not 1352P as the link to rfCarrierWave example points to.
So I looked up and found that example under 1352R, however there are two flavors
No RTOS and TI-RTOS. Which one you want me to try - does it matter? Also, what is
the expected outcome; what should I expect to see to conclude things are working?

P.S.
1) Understood your points regarding limitation/ issue involved in probing xtal pins.

2) Should mention - I can control IO lines (such as LEDs) with the BLE5 Project zero.
    on this custom board. It's just the radio part that I can't see/ get to work properly.

Use the TIRTOS version. If the xtal is not starting up the example should be stuck waiting for it to start up. 

- Have you checked voltage on the VDDR.

- Have you tried transmitting from the SmartRFStudio?

- If using SmartRFStudio also doesn't work then you might have problem with 48M crystal may be placement or routing.

VDDR is reading 1.669V

I haven't used SmartRF Studio - will read up next, on how to do that?

With the RTL-SDR, you'll only be able to measure the sub-1GHz path, of course. Anyway, the procedure I used was:

1. Use SmartRF Studio.

2. Set to Continuous TX, no modulation.

3. Start transmission.

4. Using your favorite SDR software, tune to the frequency you want (868 or 915 MHz, presumably)

5. You should see a peak around that frequency from your custom board's transmission.

6. If it is offset from center, experiment with Cap Array tuning in SmartRF Studio until it is centered.

Before doing this, my custom boards could communicate between themselves, and after tuning, they communicate with LPs also.

While this is definitely not a replacement for a spectrum analyser, it helps in this instance. If you disable automatic gain in the SDR software, you'll also get a sense of how much power is being transmitted. I'd suggest taking the board some distance away, and compare same with LP.

If your transmit power is too low, or if the harmonics are all over the place, it could indicate another problem.

Excellent! Thanks mh, appreciated.

I took a look at the schematic/ layout and could not see anything that should indicate that this board should not behave as wanted. 

Thanks TER,

That being the case - taking the investigation further, as I mentioned earlier; 
I would like to rule out any role RF switch may be playing in RF not working

With reference to my schematic if I were to remove R3 & C7 - removing U2 
(RF switch) from the picture. What values you'll recommend for: CX1, CX2?
So I can tie in P2,P3 for direct antenna connections via those 2 micro-SMA.
I've couple of "CC-Antenna-DK2" kits that I plan to use for this external Ant-
testing.

Please advise. Thanks again for your continuing help. Greatly appreciated.   

Best,
Ash

Thanks TER,

Believe I have assembly issue (possibly wrong orientation) with micro-SMA connector.

Ordering replacement parts -- will assemble and confirm; report my test results ASAP.

Hi TER,

Could you please confirm for me if this 48 MHz crystal (ABM11W-48.0000MHZ-7-B1U-T3 - datasheet attached)
would be acceptable substitute for CX2016DB48000C0FPLC1 that's used on CC1352R Lauchpad?

I see the specs are same or better - expect ESR for this is 60 Ohms (vs. 50 for CX2016DB48000C0FPLC1).

Please review and advise. Thanks.
 ABM11W-1107594.pdf 

This should help: http://www.ti.com/lit/an/swra495f/swra495f.pdf

60 ohms is at the upper limit.

I've used these successfully: https://media.digikey.com/pdf/Data%20Sheets/AVX%20PDFs/CX2016DB48000C0WLLA1_Spec.pdf

Found at DigiKey:

https://www.digikey.ca/product-detail/en/kyocera-international-inc-electronic-components/CX2016DB48000C0WLLA1/1253-1388-1-ND/5181912

Thanks mh,

I should have mentioned (per datasheet) ESR is 60 Ohms max, <30 Ohms typical.

Thanks again, appreciated.

Thanks TER,

So, looks like CX2016DB48000C0WLLA1 is my best bet as mh suggested.

CX2016DB48000C0FPLC1 is out of stock at most distributors so I need to 
look for substitute.

Apologies for the time it took me to get the hardware (connector) corrections done and test.

Happy to report now I see BLE beacon -- see ProjectZero show up in TI Android App. Now 
that it's up - next question is when I try to connect to this BLE node it times out and refuses 
to connect successfully.

I suspect it may be pointing back to caparray tuning -- following swra640a.pdf I understand
need to change SET_CCFG_MODE_CONF_XOSC_CAPARRAY_DELTA in ccfg.c. I can't 
seem to locate SET_CCFG_MODE_CONF_XOSC_CAPARRAY_DELTA or ccfg.c in BLE5 
ProjectZero project.

What am I overlooking here?

It's probably being referenced from the SDK through an include. For example, wherever your SDK is located:

simplelink_cc13x2_sdk_2_30_00_45/source/ti/boards/CC1352R1_LAUNCHXL/ccfg.c

Thanks mh,

While I look into that. Could you please share which program (windows front-end) you use with Pluto-SDR?

Screenshots of your working setup if you can, perhaps? I got  Pluto and trying to figure out how to use that
with SDR-sharp. For sniffing BLE, TI-15.4 signals from my custom cc1352r board.

Please advise. Thanks again for your help.

SE

I've tuned the cap array using IIO Oscilloscope, but any SDR software should perform the same. So for settings, in FMComm2/3/4, set your target frequency, in the main display, set to frequency domain (as opposed to time domain), measure both voltages, and that should be a good start. Hit the play button, which will display the interactive waveform, then in SmartRF Studio, set your board to the target frequency, continuous tx, no modulation, hit play. You should see something similar to the attached image. You should be able to center the freq peak by changing cap array values. 

Glad you sorted it out!