AWR1843AOP: In the custom board what are the required steps to generate the 40 Mhz clock from cryastal.

Sapana Shirsat

Part Number: AWR1843AOP

Tool/software:

Hello Team,

I have design custom board by taking reference from AWR1843AOPEVM schematic and board file. I am able to generate required output voltages 3.3V, 1.2V, 1.0V & 1.8V and same are generating across AWR1843AOP supply pins, except AR_1V8_APLL and AR_1V8_SYNTH.

At the same time, 40Mhz Crystal is not generating the clock but when I have checked the potential across AR_XTAL_P, it is coming 21mV whereas AR_XTAL_N, it is coming 640mV.

I have checked footprint, and schematic, pin connection it looks like okay.

I am able to get AR_NRST, AR_WARMRST as per mentioned in datasheet except AR_OSC_CLKOUT.

Through USB, (RS232 to UART), i have tried to flash the out_of_box_1843_aop.bin file, in same way how we use to do for evaluation board. In device manager, 2 com ports comes when we connect custom board to laptop. It is showing unexpected received data error, please find in below image for better understanding.

From the above observations, can you please guide me to what exact steps I should follow to get 40 Mhz clock across crystal?

23 days ago

0 aozer 23 days ago

TI__Mastermind 29165 points

Hello,

The crystal will start automatically once NRESET is released and all supplies are stable, there is no need to do anything to start the XTAL.

You will need to share you schematic to debug this further as there must be something wrong with your design.

Also, please confirm if this is an industrial or automotive application so that it can be directed to the correct person for support.

Regards,

Adrian

0 Sapana Shirsat 22 days ago in reply to aozer

Prodigy 40 points

Thank for your reply, Adrian.

As you mentioned I have tried by releasing NRESET, but still not able to get 40 MHz clock across the crystal on custom board.

After powering ON custom board its drawing only 140 mA where as in same (AWR1843AOPEVM) evaluation board it is drawing 300mA current, does it makes sense to not generate a 40 MHz clock?

As I am using this board for industrial application, so can I share a schematic direct to you instead of forum?

Regards,
Sapana.

0 aozer 21 days ago in reply to Sapana Shirsat

TI__Mastermind 29165 points

Hello Sapana,

Thanks, since this is an industrial application I will loop in the support for industrial radar. I am only supporting ADAS applications.

Also, it looks like there is another thread on this same topic. I will request if we can consolidate the discussion into a single thread.

https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/1513765/awr1843aop-crystal-oscillator-not-generating-40-mhz-signal

Regards,

Adrian

0 Sapana Shirsat 20 days ago in reply to aozer

Prodigy 40 points

Hi Adrian,

For me it is okay to get the solution on that thread also, it will be really helpful if you provide a solution at your earliest.

Can you share a link so that I can upload schematic for better clarity?

Regards,
Sapana.

0 aozer 20 days ago in reply to Sapana Shirsat

TI__Mastermind 29165 points

Hello,

Blake from the industrial applications team will be taking over this issue since I am supporting ADAS applications only. He will respond here shortly.

Regards,

Adrian

0 Blake Kisshauer 14 days ago in reply to aozer

TI__Expert 3640 points

Sapana,

Could you please probe the voltage across the VBG capacitor?

Thanks!

Blake

0 Sapana Shirsat 14 days ago in reply to Blake Kisshauer

Prodigy 40 points

Yes Blake,

The voltage across VBG capacitor is 0.89V.

After this I have probe the Crystal at P terminal it's showing 21mV and at N terminal it's showing 640mV, and I am not getting waveform here.

Can you guide me what exact bench test setup I should follow? Like do I need to use mmwaveic boost card with custom board?

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AWR1843AOP: In the custom board what are the required steps to generate the 40 Mhz clock from cryastal.