ads7846: data read from tsc2046 are all zeros

ads7846: data read from tsc2046 are all zeros

[Yang, Xiaopeng]

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.

Thanks,
Xiaopeng

Re: ads7846: data read from tsc2046 are all zeros

[Juha Kuikka]

On 11/8/07, Yang, Xiaopeng <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.

Re: ads7846: data read from tsc2046 are all zeros

[Yang, Xiaopeng]

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.

Re: ads7846: data read from tsc2046 are all zeros

[Yang, Xiaopeng]

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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