XCLK connection

[simon0356]

Hi !

In the readme you say that : 11-> (convert 5v to 3.3v) XCLK

Is that just a tension divisor like that : http://www.astuces-pratiques.fr/imagesarticles/24/le-pont-diviseur-de-tension-0.jpg ?

Thanks

[ComputerNerd]

I personally used a buffer and have not tried a voltage divider however you are welcome to try a voltage divider. If you are worried about noise you can always check with an oscilloscope before connecting.

[simon0356]

I'm sorry but i'm not a Electronic guru Should i connect 3.3v and gnd to arduino 3.3v/gnd ?

In both case i configure minicom at 1Mbaud 8n1 and no flow control. Is there where i should get the hex value of an image ?

[ComputerNerd]

Yes the voltage is supplied by the arduino. The image is sent without doing any conversion, in other words it just sends the data as-is.

[simon0356]

This is my connection : 0v7670

I'm sorry for lose your time, i deeply watch and try your code and got a problem with I2C, i have error with twiAddr() function.

Thanks a lot for error_led that help me ! :+1:

[ComputerNerd]

@simon0356 sorry for forgetting to respond to you. The connections are wrong and this is due to me missing some information in the README that I have corrected recently. Add a 4.7 or 10k pull up resistor to 3.3v on A4 and A5.

[rafaneri]

Hi,

I tried to use the code, but the error_led was always called. So I tried change the TWCR in twiStart to TWCR=_BV(TWINT)| _BV(TWEN); removing the twi start (TWSTA) then the error_led didn't called. However I've used the goSerial to read and see the data, but I didn't had success. I wrote a C# programming to listening the serial port, but nothing success.

Have you some trick to help me to read the data?

Thanks!

[abbanerjeersm]

Hi, I have redone the connections. Can you please comment if they are correct ?

http://fritzing.org/projects/ov7670-no-ram-arduino-uno

[themathgeek13]

@abbanerjeersm - You need a voltage divider for pin 11 to XCLK to convert 5V to 3V3. Apart from that, the wiring looks the same as mine.

@ComputerNerd - I am getting a green pixelated and noisy image...how do I correct this?

[abbanerjeersm]

@themathgeek13: My UNO clone has a 3.3v output. I am assuming I can use that ? Also, I was responding to the schematic from @simon0356

[themathgeek13]

@abbanerjeersm - I was referring to your schematic. Yes, the UNO output of 3V3 is fine (not sure about I2C though)

[abbanerjeersm]

@themathgeek13 : The schematic from @simon0356 does not have resistors connected for I2C as suggested in the readme here. I was correcting that. Also can you please share the link to your schematic ?

[themathgeek13]

@abbanerjeersm - Mine looks just the same as yours, except with pin11 divided using 4K7 and 10K to convert 5V to ~3V3.

[simon0356]

I finaly get an osciloscope to test my divider ( http://boutique.semageek.com/fr/251-powerpod-1117-3v3.html ) on xclk and this is not the solution ! with the 8MHz clock his output is about 1vpp, i will try another trick like tension divider with hight impedance (because someone told me that at low impedance (like 1700/3300 ohm) the current should be too hight)

[ComputerNerd]

@simon0356 Why did you think that would work? Did you read the datasheet? It is too slow. Switching regulators are good but only for a power source. They are not good lowering the levels of a high frequency signal. Next time read the datasheet. You need something fast enough for an 8mhz signal.

[ThomasStock]

Where in the datasheet can I see the "speed"? What keywords am I looking for (novice here)