AM263P4-Q1: Configuring the Duty Cycle of the I2C Communication Waveform

Imaoka Daisaku

Intellectual 400 points

Part Number: AM263P4-Q1

We would like to use I2C communication in Fast Mode (400 kHz) on our custom board.

when we measured the I2C communication waveform, the low period was 1.26 µs.

On the other hand, according to the datasheet of the slave IC,

the timing requirement for the low period is at least 1.3 µs.

Therefore, we would like to reduce the duty ratio.

Could you please let us know how to change this setting?

Our project is currently using SDK version 9.2.

7 months ago

0 Brennan Hartigan 7 months ago

TI__Genius 13629 points

Imaoka,

The I2C driver only supports changing the bus bit rate to the standardized 100KHZ or 400KHZ. There is not a configuration to modify the duty cycle.

Regards,

Brennan

0 Imaoka Daisaku 6 months ago

Intellectual 400 points

Hi Brennan,

I tried modifying the formula that calculates ICCLKL and ICCLKH inside I2CControllerInitExpClk() in mcu_plus_sdk_am263px_09_02_00_56\source\drivers\i2c\v1\lld\i2c_v1_lld.c,thinking that adjusting it would allow me to control the duty cycle.

For example, as shown in the figure below, by adding +3 to ICCLKL and subtracting -3 from ICCLKH, the I2C speed remains at 400 kHz, but the duty cycle appears to have been reduced.

Would making such modifications be acceptable? If there are any concerns, I would appreciate your guidance.

Regards,

Imaoka

0 Brennan Hartigan 6 months ago in reply to Imaoka Daisaku

TI__Genius 13629 points

Imaoka,

Please allow me until tomorrow to confirm if this is an acceptable way of modifying the duty cycle.

Regards,

Brennan

0 Brennan Hartigan 6 months ago in reply to Brennan Hartigan

TI__Genius 13629 points

Imaoka,

Apologies as I am still trying to confirm this with my software team.

Regards,

Brennan

0 Imaoka Daisaku 6 months ago in reply to Brennan Hartigan

Intellectual 400 points

Hi Brennan,

Have we received any response from the software team?
If there has been any progress, I would appreciate it if you could let me know.

+1 Brennan Hartigan 6 months ago in reply to Imaoka Daisaku

TI__Genius 13629 points

Imaoka,

Apologies for the delayed response. Yes this is a valid way of changing the I2C CLK duty cycle.

Regards,

Brennan

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AM263P4-Q1: Configuring the Duty Cycle of the I2C Communication Waveform