2010-03-25 12:56:46     why my bf531 can't get right picture?

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2010-03-25 12:56:46     why my bf531 can't get right picture?

macgrady tracy (CHINA)

Message: 87695   

 

hello,every one,

 

There is a question puzzing me for a long time

 

i am use bfin531 and ov7670 coms senser to capture picture

 

i am sure the ov7670 sensor is OK, and when i use the testing mode of ov7670 i can get the correct picture

 

but when i try to get capture a pict of my own, the pict is black, most of the pict is black!!!!

 

my question is :

 

what is the correct of BF531's PPI  I/O volt?  3.3v? 2.8v? 2.5v? or when the input volt is 2.2v, blackfin can recognize the I/O volt?

 

any one who can help me?

 

thanks!!!

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2010-03-25 21:54:14     Re: why my bf531 can't get right picture?

macgrady tracy (CHINA)

Message: 87703   

 

ps:

 

i means the picture  is dark ....

 

The blackfin PPI port read the 2.2V  is  "0" or "1"

 

Blackfin can support OV sensor?

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2010-03-26 05:14:56     Re: why my bf531 can't get right picture?

Michael Hennerich (GERMANY)

Message: 87733    > The blackfin PPI port read the 2.2V is "0" or "1"

 

This depends on VDDext. For VDDext = 3.3V it may read 1 on the PPI pins, but not sure it will also work on the PPICLK since VIHCLKINmin = 2.2V @ VDDextmax = 3.6Volt.

 

> Blackfin can support OV sensor?

 

You have several choices:

1) Increase OV Sensor IO-Voltage.

2) Reduce Blackfin VDDext

3) Use level shifters

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2010-04-01 05:05:16     Re: why my bf531 can't get right picture?

macgrady tracy (CHINA)

Message: 87972   

 

thanks for you replay!

 

I have resolved this problem,

 

the reson of the picture  dark is that  the I2C(on platform of OV we call it SCCB) not been set correct!

 

thanks!!!

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