I configured SYSCLK to 480 MHz and set the I2C1 peripheral clock frequency to 120 MHz. For I2C1's timing settings, I selected Fast Mode Plus (1 MHz) and applied the timing register value 0x0050174F, the setting about maximum output speed of SDA and SCL are Very High.However, when observing the I2C1_SCL line with a logic analyzer, the actual output clock frequency is only 890 kHz.
I2C clock speed is not a guarantee. It has to wait for edges to happen, so the actual clock you get is not exact like it is with SPI. This is expected and unavoidable.
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I tested this with 1 kΩ, 1.2 kΩ, and 2.2 kΩ pull-up resistors, but the SCL frequency remained unchanged at 890 kHz.Has anyone encountered this issue? Any insights would be appreciated.
I2C clock speed is not a guarantee. It has to wait for edges to happen, so the actual clock you get is not exact like it is with SPI. This is expected and unavoidable.
If you feel a post has answered your question, please click "Accept as Solution".
