Chip is 18F45K80. I changed pull-up values to 5.1K, not much difference in shape of signals, but at least now it works.
So in case of I2CWRITE, pins should be configured as input?
In your "working" example 2 you're actively driving the pins high and low.
I2C is an open-drain/collector bus where the high level speed is determined in part by the pullup values.
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Re: I2CWRITE/I2CREAD access hardware in the different way? (PCA9685 issues)
You should probably leave them as inputs.
tumbleweed - 20th December 2025, 17:39The I2C commands will change them from inputs to outputs as required to simulate an open-collector signal (high=input, low=output 0).
It would...