LP-AM263: How to configure Open drain buffer in Am263x for I2C communication

Sanith goud Kothuri

Part Number: LP-AM263
Other Parts Discussed in Thread: TMP100

Tool/software:

we are trying to implement I2c communication with TMP100 IC, but in TRM it is mentioned that I2C[1:3] instances are LVCMOS buffer (not implemented in open drain buffer), to make them open drain buffer what are the configurations we need to do and what are the registers we need to modify.
What is the use case of this register "I2C_ICPDRV"?

Thanks in advance...

5 months ago

0 Brennan Hartigan 4 months ago

TI__Genius 10634 points

Hi Sanith,

You need to configure the I2C pins to operate as open-drain outputs by configuring the I2C module to source a constant low output and toggle the output enable. The output buffer drives low when enabled and is high impedance when disabled.

I have looped in our software expert to explain how this can be done through SW.

Regards,

Brennan

0 Sanith goud Kothuri 4 months ago in reply to Brennan Hartigan

Prodigy 85 points

Thanks for your response, sure I will be happy if your expert can assist me and solve the issue

0 Brennan Hartigan 4 months ago in reply to Sanith goud Kothuri

TI__Genius 10634 points

Sanith,

You are welcome. Please expect a reply by Monday, April 21.

Regards,

Brennan

0 Shaunak Deshpande 4 months ago in reply to Brennan Hartigan

TI__Genius 16412 points

HI,

Apologies for a delayed response, I was Out-of-office, I'm not sure if you can implement/change the buffers from LVCMOS to Open drain behaviour completely from SW.

You can try to mark the GPIO pins shared with I2C[1:3] as Pull UP. (from syscfg), I2C driver will still drive the lines high and low, which can cause line contention in complex scenarios with multiple slaves with shared lines.

Regards,
Shaunak

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LP-AM263: How to configure Open drain buffer in Am263x for I2C communication