range decreased significantly after otp

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mohit3112
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range decreased significantly after otp

I am using PAN1740 , I found that there is significant range drop as compared to when i was debugging it on keil. RSSI for same distance is really less after otp , can you please explain me what might be the problem

Thanks
Mohit

JE_Dialog
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Hello Mohit, i have sent your

Hello Mohit, i have sent your inquiry to the Panasonic team (wireless@eu.panasonic.com). They will respond on here shortly.

Thanks &BR JE_Dialog

Ingo
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Hello Mohit, there is nothing

Hello Mohit, there is nothing I am aware of that the OTP has any influence in the range. Maybe you limit the output power?

BR, Ingo

mohit3112
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Hi ingo

Hi ingo
as per documentation output power of IC is fixed and can not be changed by software. Also just i modified some parts of template project all the setting related to bluetooth peripheral is still default one. There is significant loss of output power RSSI value is -85db at 1 to 2m distance after otp.

mohit3112
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i saw a change in nvds.c

i saw a change in nvds.c
.NVDS_TAG_BLE_CA_MIN_RSSI = 0x40, //0xD0,
can you please explain why this change is made . Also please suggest something to debug this range problem , i am having this problem with every IC that i OTP.

MHv_Dialog
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Hi,

Hi,

When you OTP the part, make sure that you start by reading the OTP header from the chip, then make your modifications and burn. There are RF trim settings programmed in Dialog's production that should not be altered. This could explain the difference between a programmed OTP and running from system RAM.

Ingo
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Hi Mohit, -85 is not a

Hi Mohit, -85 is not a unrealistic value for that distance. What is your reference when you say after OTP, do you mean that if you are working in debug mode there is a difference? If so can you describe what the difference is?

mohit3112
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Hi Ingo,

Hi Ingo,
yes when in debug mode rage is just fine so if i stand at a distance of 1 m RSSI is -55db to -40db ( in debug mode ) . now when i do OTP and stand at similar distance (1 m ) RSSI is about -85db to -95db . It's really unlikely, but i have done OTP of two module and i see a noticeable fall in their range. As far as i know we cannot change transmit power in firmware. This is a rather hard problem to debug , is their any suggestion on test that i can do on my device.

Tom Lock
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Mohit / Ingo:

Mohit / Ingo:

Was this loss of distance issue ever resolved?
What sort of reliable communication distance can I expect between two PAN1740 modules?

Thanks,
TL

mohit3112
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It's still there , PAN1740

It's still there , PAN1740 have really bad range it's ok for wearables but really bad for beacons, will not recommend it to anyone

JE_Dialog
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Hello Mohit, can you tell me

Hello Mohit, can you tell me which SDK you built this on ? There is no issue with the DA14580 , but we did idenitify an issue with SDK3.0.4 which has been fixed in3.0.6 and onwards which in very isolated circumstance could cause the kind of effect you are seeing.  BR JE_Dialog

mohit3112
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i am directly moving to

i am directly moving to latest 3.0.8 SDK will update after i do otp.

mohit3112
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RSSI at 1 m is -93 , i just

RSSI at 1 m is -93 , i just otp a PAN1740 , range is decreasing after otp , is that a xtal trim value issue ? please help !!

Ingo
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Hi Mohit;

Hi Mohit;
The xTal is calibrated in the OTP header in our factory. How many times do you read out the RSSI. Ususally it changes.
Best regards,
Ingo

mohit3112
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The value i am mentioning is

The value i am mentioning is not a single shot value it was -93 for a long time ( i am reading it every 5 sec) , when i moved it really close to phone ( iphone 6 is used for testing) it became -63 .