DA14580 communication problems with higher supply voltage

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mratajski
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DA14580 communication problems with higher supply voltage

Hello Dialog Team,

We are using DA14580 on PAN1740 module.
The module is used on a coin battery powered products.
On the product a microcontroller communicates with DA14580 over UART.

We are experiencing with some modules connection problems.
We have noticed that it happens when battery voltage is higher like 3.1V - 3.3V.

First idea was signal level incompatibility (high level output of DA14580 is not smaller than 1.88V and ucontroller high level input threshold is bigger than 2.5V at 3.1V),
but signal levels look fine.

Can we run in some timing issues with higher supply voltage?
Is there any some more detailed description of IO levels (i.e. in relation to supply voltage)?

Thanks.

Device: 
mratajski
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I have found out that delay

I have found out that delay of boot process after reset can slightly vary with supply level.
We have timeout of around 120ms (to take into account 100ms delay in boot process).
With lower supply voltage it is fine.
However with higher supply voltage it is not enough...
What is the worst case (over temperature and voltage) delay from reset to start of UART boot?

PM_Dialog
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Hi mratajski,

Hi mratajski,

Apologies, I am not completely sure if I understood your question, so could you please clarify it a little bit more? What are you trying to accomplish?  Do you have the PAN1740 module and you want to power it up via a coin cell battery? Are you have implement a custom board with DA14580 and you have it connected with the PAN module? The recommend and maximum voltage rating are demonstrated in the tables 257 and 258 of the DA14580 datasheet.

Thanks, PM_Dialog

mratajski
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Hello,

Hello,

We are using Panasonic PAN1740 Bluetooth module.
The module is just a wrap-up around DA14580 with some external components (like antenna, RF shield).
There is no buffering or power conversion on the module, so we make direct connections to DA14580 in fact.

Our products are powered wit coin batteries (like Varta 6450 / CR2450, nominal voltage 3V).
The coin batteries have variable voltage over the time. They have their initial voltage higher than nominal (some quite higher 3.2V-3.3V).
This is where we have run into communication problems with DA14580 despite driving it within electrical specification from the datasheet.

I have observed that timing of UART communication (booting) is supply voltage dependent.
I wonder if you have worst case timing specification of UART communication (over voltage and temperature).
We would like to set time-outs in our software accordingly (to have some margin, but not something excessive).

The other question was regarding IO specification (as it was my first suspicion).
Especially output 3V high voltage would be interesting. The data sheet specifies only minimum of 1.88V (Table 336).
Do you have any characteristics of IO ports depending on supply volatage/output current?

Regards,
Michal

PM_Dialog
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Hi mratajski,

Hi mratajski,

We don’t have any available DC characteristics of IO ports depending on supply voltage/output current. You could find the DC characteristics in the DA14580 datasheet.

Thanks, PM_Dialog

omesa
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Hello,

Hello,
in my project ultra low power geigercounter stick I have a 3.6 V for the PAN1740 module, without any problems !
cheers Siegmar

PM_Dialog
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Hi omesa,

Hi omesa,

Thank you for your information.

Thanks, PM_Dialog

mratajski
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OK. It is clear. Thank you.

OK. It is clear.
Thank you.