I2C failure - SCL glitches

Srinivas Jagarapu

Other Parts Discussed in Thread: OMAP-L138, OMAPL138

Hello,

In our designs we are using OMAP-L138 and seeing I2C failures. I2C0 is connected to EEPROM, Temperature sensor and to a I2C mux.

Through I2C mux OMAP-L138 talks to a third-party power supply.The I2C device address on the third-party power supply is 0x10.

Below is the capture of one such failure - part of write transaction.

The actual transaction should look like below.

We are seeing glitches on SDA also. but mostly when the SCL is low.

Regards,

Srinivas.

over 8 years ago

Titusrathinaraj Stalin over 8 years ago

TI__Guru** 116100 points

Dear Srinivas,
Are you getting any problem (i2c read/write) when you see the glitches ?

Srinivas Jagarapu over 8 years ago in reply to Titusrathinaraj Stalin

Intellectual 510 points

Hi Titus,

Yes, we see I2C failure when there is glitch on the clock.

Below is the case. After addressing the slave with write there is no acknowledgement. I think this is due the glitch - clock cycle stretched?

I have attached the successful transaction in the first post.

Regards,

Srinivas

Senthilkumar Srinivasan over 8 years ago in reply to Srinivas Jagarapu

TI__Mastermind 43660 points

Srinivas,

Are you seeing failures/spikes when you access any particular slave ?

Could you isolate the slaves one by one and check the data transfer ?

Regards,
Senthil

Srinivas Jagarapu over 8 years ago in reply to Senthilkumar Srinivasan

Intellectual 510 points

Hi Senthil,

Yes, the failures are with specific slave.

A direct question, what are the scenarios the below circled spike comes?

Does it due to slave was trying to stretch the clock?

Regards,

Srinivas

Senthilkumar Srinivasan over 8 years ago in reply to Srinivas Jagarapu

TI__Mastermind 43660 points

Srinivas,

The spikes that you are observing are not produced by the OMAPL138 device but by the hardware behind. What is the I2C frequency you are transferring data ?

Have you seen any improvements with lower frequency ?

What is the slave device that you are seeing this issue ?

Regards,
Senthil

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I2C failure - SCL glitches