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Linux/TSC2007: TSC2007 I2C ISSUE

Part Number: TSC2007

Tool/software: Linux

Hi everyone,

 
I'm developing a new board based on the IMX6.

I have driven a touch screen on I2C bus 3.

 

Sometimes it's can work correctly.

 

Sometimes I get error as follows:

tsc2007 2-0048: dbg i2c io error: -5.
I found host can't communicate with tsc2007,the touch screen chip.

When host have sent 0x90 to I2C bus.But there is no ack from bus.

The corresponding waveform is as follows:

 

Does anyone know what I am doing wrong? Any clue about that error?
 
Kind regards
  • Li Hu,

    Sorry for the long delay in response on this. I noticed that you have two postings on the same device. I assume the schematic in the other post applies to this circuit.

    1. Looking at your I2C waveforms, it appears that you are getting very nice clean waveforms. Based on your scope capture I think your t-high = t-low = 8us. This meets the minimum requirement. You may want to check the other timing as shown on page 6 of the data sheet. I believe that you may be meeting the timing requirements, but timing violations is a common cause of intermittent data communications errors.
    2. Also, you are using the correct address according to the schematic you provide in the schematic give in the other post.
    3. You say that you are getting proper operation sometimes. How often does the communications fail and how often does it work?
    4. Are all the failures on one set of hardware?
    5. Can you confirm that the device power and ground are connected? I know that this is pretty basic and that the schematic show it is connected, but I always like to double check the basics. This is especially true in this case as the waveform looks pretty clean and you are seeing intermittent operation.
    6. Your other posting discusses a different intermittent operation. In this case the PENIRQ output is activating intermittently. Is this intermittent operation on the same PCB? Is it possible that this device has been damaged?