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LPC804 I2C: Input clock and open drain mode

Question asked by Oliver Kraus on Nov 12, 2019
Latest reply on Nov 13, 2019 by ZhangJennie

Dear Community

I have two questions regarding the LPC804 I2C subsystem


Question 1:

Table 221 (section 15.7.1) of the LPC804 user manual provides some settings for the I2C timing. To me only the row with 12 MHz seems to be useful, other clock input rates are not possible from my perspective, or did I miss something?

Especially one row assumes 30 MHz clock input and two more rows assume 24 MHz clock input to the I2C subsystem.

How can I drive the I2C subsystem with 30 MHz or 24 MHz?

The highest clock selectable via "LPC_SYSCON->I2C0CLKSEL" seems to be 15 MHz.


Question 2:

Do I need to enable open drain mode for the GPIO ports connected to I2C SDA and SCL signals?