QN9090 - Hardware Considerations

[shai_b]

Hello team,

My customer is planning to start drawing his schematics with QN9090 and got the inquiries below:

1a. What are the JTAG pins (for flashing and debug the device)? 

1b. in case the customer wants to works with SWD and JTAG, whats are the pins?

 bb. Could you please explain the main difference when working JTAG vs SWD?

1c. if there is any recommendation/guidelines for JTAG pins such as external pullup?

2.is there an option to run QN9090 without external crystal 32khz and 32mhz?

please advise back, thanks in advance

Kind regards,

Shai

[Sebastian_Del_Rio]

Hi Shai, I hope you're doing well!

Could you please take a look at the QN9090 Module Development Reference Manual document included in the QN9090 Reference Design Files package?

It includes information about some different things to consider when designing a module or board implementing this MCU, as well as some more general information, and the schematics for the module, carrier board, and others included.

Could you please take a look at it to see if that's the information you need?

Please let me know if you need any more information.

Take care, best regards,

Sebastian

[shai_b]

Hi Sebastián Del Río‌

according to the reference design, it seems to be in the QN9090-DK has to implement the JTAG (only the SWD) since I did not found where JTAG_TDI pin is connected to the device itself.

second thing regards working crystal less, I did not found any guides that explain if the devices could work without the 32Khz and 32MHz.

I am assuming the high frequencies crystal aka 32Mhz is a must-have for the RF PLL and such.

but the 32Khz I do believe we can operate without, but I did not found any confirmation from the documents on that side (and I am sure there are also SW changes need to be done to select the CLK source)

Please advise back? your support is highly appreciated.

Many Thanks

Kind regards,

Shai

[Sebastian_Del_Rio · Accepted solution]

Hi Shai,

The JTAG implementation on the QN9090 Family of MCUs uses the SWD interface to reduce the amount of pins needed to debug.

As for the external XTALs, it is recommended to use an external XTAL for the 32kHz clock, as it can provide additional accuracy compared to the internal FRO32k.

The 32MHz XTAL is mandatory, as it is used for the radio, which requires a very precise 32MHz clock source. A +-50ppm accuracy is needed for Bluetooth Low Energy operation.

More information about these crystals can be found in the User Manual and Datasheet for the QN9090/9030.

Please let me know if you need any more information.

Best regards,

Sebastian

[shai_b]

Thank you.

KR,

Shai

[shai_b]

Hi team,

There is any update?

I'm waiting for your kind response, thanks.

KR,

Shai