Voltage Leakage in GPIO pins ! EEPROM interface

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hrg
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Voltage Leakage in GPIO pins ! EEPROM interface

Hi Dialog Team

We are using the DA14580 dev kit(Expert) and we use the setup in boost mode. We noticed that there is some voltage level of 2-2.5 volts in the GPIO pins (especially in P0_2 ,P0_3 we found this when we were trying to execute the I2C example !) So in boost setup the daughter board is supplied with 1.5 volts ,but these gpio pins measured nearly 2-2.5 volts !! There is some breakthough from the motherboard straight to these GPIO pins ! even when the daughterboard is removed the GPIO pins hold these voltage levels !

I have attached the Snapshot of the Mother board (Expert) ,could you please for any error in jumpersettings inorder to remove the voltage across the GPIO pins

https://www.dropbox.com/s/yjdvblme1tskw0a/MotherBoard.jpg?dl=0

Thankyou.

JE_Dialog
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Hello hrg,

Hello hrg,

i took a quick look and jumper settings look fine.  What you might be seeins is the ports scanning - these are the ports that may be for example SPI , so they will be scanning for peripherals. It depends of course on what you have these configured to, but by defauly, P0_2/3 will be part of SPI.  When you remove the daugtherboard, it will continue to function for some time as the distributed capacitance across the board can continue to power the device for a short time (since its so low power).

BR JE_Dialog

hrg
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I removed the Daughterboard

I removed the Daughterboard and waited for one hour ,& these GPIO pins some measure 2.1 volts ,some measure 2.9 volts !! since we are using 1.5 volt boost mode for daughtercard & if we plug it the wont it conflict with the motherboard voltage ? So when we connect I2C pheriperal to P0_2 ,P0_3 it is not working because these pins are in different voltages and higher that the DA14580 supply (1.5v). !

Thankyou

BB_Dialog
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Hi hrg,

Hi hrg,

in boost mode, by default all GPIO's are connected to the 3V rail, that is Vbat3V.
In boost mode, Vbat3V is generated from the internal booster, and will be 2.7V by default.

In your software you can define to connect them to the 1V rail (Vbat1V), or leave them connected to the Vbat3V rail but set the Vbat3V to 1.8V (the lowest possible).

1) set to Vbat1V rail:
P01_PADPWR_CTRL_REG (0x50003070)
7:0 R/W P0_OUT_CTRL 1 = P0_x port output is powered by 1V rail
0 = P0_x port output is powered by 3V rail (default setting)
bit 0 controls the power of P0[0], bit 7 controls the power of P0[7]

2) Set Vbat3V to 1.8V:
DCDC_CTRL2_REG (0x50000082)
Bits 11:9 - DCDC_VBAT3V_LEV : value: 0x00 (default value = 0x6).

Please note that during booting, and OTP not burned, all P0 GPIO's are scanning for peripherals (SPI, UART, ) and these will have signal peak levels of about 2.7V in that case.
And with OTP burned, the bootrom still defines the supply rail of the GPIO's to Vbat3V, and its voltage is set to 2.7V in order to be able to read the OTP header.

Best regards, BB_Dialog.  

hrg
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Thankyou BB_Dialog !!

Thankyou BB_Dialog !!
i will check it once and come back to you.Meanwhile when i remove the Daughter card ,in the mother board still there is some 2-2.9 volts across the some of the GPIO pins J1 ,J2,J3,J4 .why ??

BB_Dialog
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Hi hrg,

Hi hrg,

normally only some voltage at pins P0_4, P0_5 (UART from FTDI chip) are present: remove J25 jumpers and the voltage should be 0V;
and at P1_4(SWCLK), P1_5 (SW_DIO), these are the JTAG/JLINK lines.
The others should be at 0V.

Best regards, BB_Dialog.

 

hrg
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Hi BB_Dialog

Hi BB_Dialog
In bare motherbord , P0_2 - 2.9volts and P0_3 - 2.1 volts .I removed the jumpers J25 ,but still the problem exists !! Can you check once and acknowledge me ?

Thankyou

BB_Dialog
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Hi hrg,

Hi hrg,

P0_2/P0_3 are for UART CTS/RTS . J26 is for these. In my board J26 are not placed.
In my case, the voltages are 0V.
What is your MB revision? Is it REV C2?

Please refer to schematics available on this site.
http://support.dialog-semiconductor.com/system/files/resources/580-mb-vc2-sch.pdf 

B.R., BB_Dialog

 

 

hrg
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Hi BB_Dialog !!

Hi BB_Dialog !!
I removed the J26 ,now the voltages are zero as you mentioned ! Now I tried with I2c EEPROM example its working fine with my EEPROM & made to boot my application from it :) !!
Here are the doubts i have now
1) now i have disabled the Uart CTS/RTS (removing J26) ,is it okay to disable these ,i mean when do we need uart cts/rts ??

2) and also for EEPROM am using external pullups of 10k -is it mandatory ?? (because datasheet of EEPROM(AT24C1024B) dint mention any pull-up resistors )

Thankyou

BB_Dialog
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Hi hrg,

Hi hrg,

- RTS/CTS very rarely used. I think only for the USB Dongle Proximity Monitor project.

- Yes, for I2C external pull-ups are required, 4k7 or 10K are fine. For I2C these are not provided internally.

B.R., BB_Dialog.

hrg
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Thankyou BB_DIALOG !

Thankyou BB_DIALOG !

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