Re: ads7846: data read from tsc2046 are all zeros

["Yang, Xiaopeng" <xiaopeng.yang@windriver.com>]

Resolved, the tsc2046 wouldn't be power on if the LCD module is not enabled.

Xiaopeng

Yang, Xiaopeng wrote:
> Hi all,
> 
> I captured the signals of the host-side pins of tsc2046, the SPI pins 
> and PENIRQ work correctly except DOUT remains LOW during CS is active. 
> That's why all read values are zore.
> 
> It seems like the tsc2046 doesn't work at all. I measured the voltage of 
> the power supply of tsc2046, the Vcc is only 0.93V. This shouldn't 
> happen in the normal operation. Maybe there is a switch to turn the 
> power on for tsc2046?
> 
> Thanks,
> Xiaopeng
> 
> Juha Kuikka wrote:
>> On 11/8/07, *Yang, Xiaopeng* <xiaopeng.yang@windriver.com 
>> <mailto:xiaopeng.yang@windriver.com>> wrote:
>>
>>     Hi all,
>>
>>     I'm working on the tsc2046 touchscreen controller (using ads7846
>>     driver) on
>>     sdp2430 v5.0.1 board. I can't get the touchscreen work with the
>>     linux-omap
>>     git tree. The driver builds, boots and register itself with no 
>> problem,
>>     interrupts can also be triggered when touching the panel, but no 
>> input
>>     events can be read. By enabling debug output, I finally found that
>>     all the
>>     values read from tsc2046 are all zeros.
>>
>>     Does anyone encounter the same problem? What could be the root cause
>>     for
>>     this problem? Any suggestions are welcome.
>>
>>
>> I'd check the pin muxes on the input (SPI I'm guessing) device you are 
>> using to connecto to tsc2046).
>> If still nothing I'd hook up logic analyzer to the SPI lines and see 
>> what's happening.
>>
>>  - Juha
>>
>> -- 
>> Madness takes it's toll. Please have exact change.
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