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Troubles using the ADE7880 Evaluation board with an external MCU (I2C)

Question asked by p301 on Mar 17, 2014
Latest reply on Mar 21, 2014 by p301

Hi,

I am trying to use the ADE7880 evaluation board with an external MCU with I2C communication.

I chose Vin = 3.3V for all of my circuits.

In order to use an external MCU, I soldered the JP74 JP73 and JP72 between pin 1 and 2.

I closed the JP21 jumper in order to tell the NXP that I am using an external MCU. I pressed the s2 reset button.

 

My MCU is connected on P17 with the followed signals :

MOSI_SDA_EXT

SCLK_SCL_EXT

IRQ1B_ISO

IRQ0B_ISO

RESB_CTRL

PM1_CTRL

PM0_CTRL

 

Here is the problem : When I just press s2 (and then release it), my MCU is not able to set PM1_CTRL to 0, the PM1_CTRL goes to 2V and in the other side of the insulator PM1 value is still 3.3V (so the insulator consider that 2V is equal to the logic value 1).

 

When I press s2 (and DON'T release it), my MCU is able to set PM1_CTRL to 0, and the ADE7880 goes in PM0 mode (I can see the CR5 Led ON meaning that the ADE7880 has finished it's PM0 setup.)

 

So my question is : How can we disconnect the NXP ? Did I missed a step ?

 

Note : The consumption of all my circuit (with the ADE7880 Eval Board) is 100mA when s2 is released and 27mA when s2 is pressed.

Thanks for your answers.

Best regards,

Pierre

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