topic Re: single carrier frequency in Wireless MCU

single carrier frequency

Lin-gy — Wed, 09 Feb 2022 05:49:57 GMT

Hello.

We are developing a new bluetooth Blood Pressure Monitor (BPM). The bluetooth IC is QN9021-DY (maker : QUINTIC).

Now we are getting the license of Radio Transmission Equipment Type Approval Certificate in China.But when we test the BPM in the lab. , we found the single carrier frequency is out of the standard ( the standard is : 2402-2480 MHz).The test result is 2.40193990 GHz. So it is NG in the test.

When we adjust these three parameters (2402 , 2444 , 2480) on the software of Bluetooth firmware, but the test result is still NG. The software of Bluetooth firmware was downloaded from NXP.

Gould you give me a favour ,how to modify the software to pass this test? Please give me some suggestion.

Thank you very much!

Re: single carrier frequency

mario_castaneda — Wed, 09 Feb 2022 17:11:41 GMT

Hi @Lin-gy,

I hope you are doing great.

Is it possible that you could share the SDK version that you are working on?

C:\nxp\QN902x_SDK_1.4.0\Projects\BLE\prj_fcc_ce

I am assuming that you got these images from your custom board? Am I wrong?

Did you test with our QN9020 Evaluation board?

Regards,

Mario

Re: single carrier frequency

Lin-gy — Thu, 10 Feb 2022 01:45:25 GMT

Dear Mario,

Thank you for your reply.

Yes. I can share the version I working. But it's almost the same as the version loading in the net.Please found the attachment for details.

You art right . I got these images from our board. In fact , we had passed the test two years ago and got the license in the other model. That PCB layout of the bleutooth circuit is the same as this PCB.Last time we don't need to change anything and pass the test .But this time is NG in this model.So it puzzles me.

No. I haven't test your QN9020 Evaluation board. I got this board a few days ago.And they told me that there is something wrong in the Uart of your QN9020 Evaluation board. But I will try when going to the lab. next time.

Best regards,

Lin

Re: single carrier frequency

mario_castaneda — Thu, 10 Feb 2022 16:42:52 GMT

Hi @Lin-gy,

You are working with a previous version for the QN9020 Dev Board.

Please look at the link for our Dev Board. However, what is the SDK version that you have working on?

The last SDK release that we provide is the SDK 1.4.0. Is the same version that you have?

You could look at some of the AN that we provide for a custom design.

Antennas Design:https://www.nxp.com/docs/en/application-note/AN2731.pdf

Hardware Application Note: https://www.nxp.com/docs/en/application-note/AN11814.pdf

Regards,

Mario

Re: single carrier frequency

Lin-gy — Sat, 12 Feb 2022 08:00:58 GMT

Dear Mario,

I think we aren't working in the last SDK version.Could you give me SDK 1.4.0 download link?

My PCB hardware is the same as the application suggestions.Do you doubt the single carrier frequency problem is caused by the ANT?

I shair my PCB layout,Do you have any suggestions?

Best regards,

Lin

Re: single carrier frequency

mario_castaneda — Mon, 14 Feb 2022 17:22:40 GMT

Hi @Lin-gy,

Please follow the next link QN9020. Look at the Software Section.

Do you doubt the single carrier frequency problem is caused by the ANT? I shair my PCB layout,Do you have any suggestions?

I am checking the files that you shared, and I will provide if we find any issues or if we could provide any feedback.

Regards,

Mario

Re: single carrier frequency

mario_castaneda — Tue, 15 Feb 2022 16:45:53 GMT

Hi @Lin-gy,

I hope you are doing great.

I received some feedback from the validation team the 2.40193990 GHz is under the Bluetooth spec. your design seems to be correct.

About QN902x, you can fine-tune the load cap by modifying NVDS tag 16(XCSEL).
Please look at the image attached, this could help with the PCB design.

Regards,

Mario

Re: single carrier frequency

Lin-gy — Wed, 16 Feb 2022 01:35:57 GMT

Dear Mario,

Thank you very much for your feedback. It's very helpful.

I have a question about the picture showing( XCSEL Number 0xA)

About this value, is the byte from 0- 255 ?

I have another question about tiggering.

Now we are using Uart to tigger QN9021 working.Except this method , we found the SW tiggering is OK too.But in the software ,GPIO_P15 is tiggering for QN9020 ,not QN9021. So which PIN is tiggering for QN9021?

Best regards,

Lin

Re: single carrier frequency

mario_castaneda — Wed, 16 Feb 2022 16:28:06 GMT

Hi @Lin-gy,

The XCSEL value is the cap load of 16 MHz crystal oscillator; the default value is 0x11; adjust according to the specific PCB design and crystal used in real applications. In this case, the range is 0-255.

What is the example that you modified or the UART that you want to work with?

Regards,

Mario

Re: single carrier frequency

Lin-gy — Thu, 17 Feb 2022 01:24:31 GMT

Dear Mario,

>>What is the example that you modified or the UART that you want to work with?

Sorry , my expression is not clearly.

At the same BPM (Blood Pressure Monitor),if we solve the single carrier frequency problem, we will send the BPM to the government related laboratory testing for the license.But how to tigger the sigle carrier is a problem.Now we use the serial port to trigger the single carrier through the auxiliary tool.But this mothed is diffcult for the laboratory member.If tiggering through the switch ,it's easy for them. But we found the bluetooth firmware, GPIO_P15 is tiggering for the IC QN9020 ,not QN9021.

So we want to know which PIN of QN9021 can tigger the single carrier in high level or in low level ?Is P2_6 OK ?

Best regards,

Lin

Re: single carrier frequency

mario_castaneda — Thu, 17 Feb 2022 19:01:59 GMT

Hi @Lin-gy,

Sure, in the QN9020 Evaluation board the button is working with the GPIO_P15. You could use, in this case, a different button to trigger the events that we have in the example.

Regards,

Mario

Re: single carrier frequency

Lin-gy — Fri, 25 Feb 2022 03:15:05 GMT

Dear Mario,

As I said last mail , I want to tigger the sigle carrie with P2_6 in low level. After supplying the power press the button ( P2_6 ) in low level , then the sigle carrie can be tiggered. I used this method to tigger the bluetooth.

Last week , I made the samples and sent to the lab. for testing. But yesterday, the lab. telled me that there is no sigle carrie from the samples. I think the bluetooth was not tiggered. I modified the firmware as the picture 4 and 5 in attachment.

Whether my modificaion is correct? Why the sigle carrie can't be tiggered?

Best regards,

Lin

Re: single carrier frequency

mario_castaneda — Mon, 28 Feb 2022 17:28:02 GMT

Hi @Lin-gy,

You are modifiyng a different define. you have to edit button 1 in this case.

#if defined(CFG_FCC_CE_TEST)
#define BUTTON1_PIN (CFG_FCC_CE_CTRL_PIN)
#else
#define BUTTON1_PIN (GPIO_P25)//(GPIO_P14)
#endif
#define BUTTON2_PIN (GPIO_P15)

#endif

/// FCC/CE test control pin
#define CFG_FCC_CE_CTRL_PIN GPIO_P26//GPIO_P15

Also, by default the device is setting the PIN2.6 as PWM, you have to modify that.

syscon_SetPMCR1(QN_SYSCON, P20_GPIO_16_PIN_CTRL | P21_GPIO_17_PIN_CTRL | P22_GPIO_18_PIN_CTRL | P23_GPIO_19_PIN_CTRL | P24_GPIO_20_PIN_CTRL | P25_GPIO_21_PIN_CTRL | P26_GPIO_22_PIN_CTRL /*[MC]*/ //| P26_PWM1_PIN_CTRL | P27_GPIO_23_PIN_CTRL

Please let me know your findings.

Regards,

Mario

Re: single carrier frequency

Lin-gy — Thu, 03 Mar 2022 08:49:07 GMT

Dear Mario,

Thank you so much for your help.

I modified the firmware as your suggestion and tested it in the lab. But there is no single carrier after using the new firmware . I took a vidio ,please find the attachment.

Where I need to modify, too ?

Best regards,

Lin

Re: single carrier frequency

mario_castaneda — Thu, 03 Mar 2022 21:33:48 GMT

Hi @Lin-gy,

Did you try the same example with the QN9020 Evaluation Board?

What are the values that you have in the next const variable?

const uint32_t freq_tab[] = {2402, 2440, 2480};

You could try to only define 2480 or press the button some times.

Regards,

Mario

Re: single carrier frequency

Lin-gy — Sat, 26 Mar 2022 02:34:08 GMT

Dear Mario,

Sorry to tell you the good news so late.

We have pass the single carrier test in the first of Mar. Your suggestion is very helpful.

Thank you so much for your help.

Best reagrds,

Lin