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ADE7763 Interrupts ZXTO and SAG - different behavior between two devices

Hello,

I have two ADE7763 connected via SPI to MCU (ATTINY416). ZXTO Interrupt work and SAG Interrupt don't work at the first device. ZXTO Interrupt don't work and SAG Interrupt work at the second device. Why?

Devices Registers Setup:
SAGCYC = 0x0A
SAGLVL = 0x12
MODE = 0x0004
IRQEN = 0x1010 for ZXTO or 0x0012 for SAG detection

Notes:
-SS/ and IRQ/ are wired individually to MCU
-ZX Interrupt work with both devices.

Best Regards

  • Hi,

     

    There a couple different things that could be causing both of these interrupts to fail. It would be helpful if you provided waveform captures of the voltage channel as well as the circuit you are using to test the parts. 

  • Hello,

    Schematic and Waveforms for download.

    Waveforms measured at pins 7. DC voltages are 0V.
    At pins 6 are 0V without AC or any glitches.
    Supply voltage is 5.02V.

    Voltages are referenced to AGND pins of devices. DC voltages measured with digital multimeter.

  • Hello,

    I went back to the problem. I have 2 questions:
    1. It's possible use two devices with single crzstal?
    2.What is the IRQ output state in RESET? 

    Best Regards

  • Clocking of ADE7763

    Analog Devices had quality and fast technical support. This forum is just a bad substitute.

  • Can you capture with a scope  the signal at the clkin pin of the second part? 

    It is possible the crystal is loaded to heavily  27pf + crystal in pin capacitance + parasitic. 

     

    With the power off measure capacitance from clkin on second part to gnd. You may need to resize the load cap on the clkout pin on part 1. 

    As a test try a smaller cap like 20pf does it work then? you need to have the load capacitance correct or the part may not start up. make sure the reset pin is tied high with a resistor.

    If you use a buffer at the clockin output you will have no issues as the clock out pin is designed to drive 1 cmos input.

    I am not sure what the IRQ pin is in reset this is an older part. I do suggest you tie reset to 5v with a 10k resister 

    What micro are you using with this part? This is a 5v part and a 3v3 micro may have issues this part without some kind of level shifting.

    Dave

  • 1. MCU have VDD = 5V. ADE7763 is wired to MCU ports directly.
    2. IRQ have pullup 3k3
    3. RESET is drived from MCU push pull output
    4.Node CLKOUT first device, CLKIN, second device have signal 3,579545MHz, CMOS levels
    5.External CLK generator is a better solution.