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I2C logic low level did not to 0.

spark wang

The test of I2C signal found that the logic low level could not be lowered. It was pulled up to 3.3V through the external 1K resistor, and the logic low level of I2C was about 0.7V. In addition, there was a step of DAT signal, please help to check  what reason caused the problem.

PIR-Ritter Camera SCH.pdf

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    Hi,

    with 1K pull-up, you have 3.3mA current over I2C pin. If the pin is configured in standard drive mode, output voltage will be about 0.6V (see figure 3). You can either configure SCL and SDA in high-drive mode (NRF_GPIO_PIN_H0D1), or use less strong pull-ups (in most cases 2k2 is enough for 400kHz).

    The step on SDA is caused by ACK pulse from replying device with higer drive stength.

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  • 0

    Hi,

    with 1K pull-up, you have 3.3mA current over I2C pin. If the pin is configured in standard drive mode, output voltage will be about 0.6V (see figure 3). You can either configure SCL and SDA in high-drive mode (NRF_GPIO_PIN_H0D1), or use less strong pull-ups (in most cases 2k2 is enough for 400kHz).

    The step on SDA is caused by ACK pulse from replying device with higer drive stength.

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