How is 20736 detect battery voltage?

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Anonymous
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We have a 20736 Tag3 board,and when test with it ,find battery voltage is allway 88 with app "hello server".

What's wrong with it?If we want detect battery voltage,how to work?Any hardware to add?

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1 Solution
Anonymous
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Hi wangguoshun,

Just to clarify, did you understand the answers?

The firmware does not need to change because both SoC and SiP use logical P15.

The hardware (schematics and PCB layout) is different.  You should connect Vbat to the SoC's pin 31 or the SiP's pin 41.

Cheers,

Gil

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9 Replies
Anonymous
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See this post:

Battery Measurements on BCM20736S

Cheers,

Gil

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Anonymous
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Thanks gdepaula

I was just getting ready to post links to both of those threads as well.

Appreciate the help.

sambhav dmiya kwang

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Anonymous
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We use 20736 soc.We learned that 20736s battery detecting is on P15.What about 20736 soc?Is the same?Is any hardware to change?

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Actually P15 refers to that of the SOC, not the SIP module.

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MichaelF_56
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Logical Pin (Firmware) P15 is also mapped to Physical Pin 41 on the SIP module as well.

This pin/GPIO is referenced in the example here as an input to the A/D converter: Battery Measurements on BCM20736S

P15-SIP.png

Anonymous
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Do you use BCM20736 SoC? not 20736S SiP module?

hello_sensor uses P15 as battery voltage A/D input.

If you use 20736 SoC, it's on pin#31.

I think it connects to 3.0V on your tag board, right?

(88% is close to 3.0V when 3.2V is maximum and 1.8V is minimum.)

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Anonymous
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Hi wangguoshun,

Just to clarify, did you understand the answers?

The firmware does not need to change because both SoC and SiP use logical P15.

The hardware (schematics and PCB layout) is different.  You should connect Vbat to the SoC's pin 31 or the SiP's pin 41.

Cheers,

Gil

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Anonymous
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Thank you! I have changed to our design.

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