The signal on the bus is the same.
Just the name is different.
So to talk to the part using Linux, use the address in "7-bit" format,
which for your part is 0x21.

If you are writing in C, you will use i2c-dev and ioctl

If you are writing in Python 2.7, you will use SMbus and something like the
Adafruit Python I2C BBB-IO

Best regards,
--- Graham

==


On Thu, Jun 25, 2015 at 1:27 AM, 멘지 <[email protected]> wrote:

> thank you for your answer
>
> When the '1' shift is not this lead?
>
> Then how to i write register in Ov7670  ??
>
> I must register modification in OV7670
>
> I wonder how to I2C write .
>
>
> *Please understand the lack of  my English skills. ^^ ;;;;
>
> thanks
>
>
>
> 2015년 6월 25일 목요일 오전 2시 18분 37초 UTC+9, Graham 님의 말:
>
>> There is an "8 bit" representation of an I2C address, where the bottom
>> bit is actually the Read/Write bit and is, by convention, set to zero to
>> describe the address.
>>
>> There is a "7-bit" representation of an I2C address, where the address is
>> shifted one bit to the right, so the read/write bit disappears and is not
>> part of the address.
>> Half the manufacturers do it one way, the other half the other way.
>>
>> Linux/Debian uses the 7 bit representation.
>>
>> 0x42 >> 1 = 0x21
>>
>> --- Graham
>>
>> ==
>>
>> On Wednesday, June 24, 2015 at 3:13:48 AM UTC-5, 멘지 wrote:
>>>
>>>
>>> I'm trying i2c bus on BBB
>>>
>>> slave module is OV7670 ( CMOS Camera )
>>>
>>> OS is angstrom
>>>
>>>
>>>
>>> <https://lh3.googleusercontent.com/-zT9VFvtWOmo/VYpkZj8P2MI/AAAAAAAAFDw/Abor6TYsMrg/s1600/dd.png>
>>>
>>>
>>> when i connect ov7670 on BBB  P9 Header (19,20)
>>>
>>> and command i2cdetect -r -y 1
>>>
>>> look at the picture above you fine '21' is creating
>>>
>>> 0x21 is slave address ????
>>>
>>> but slave address of ov7670 is 0x42 in datasheet
>>>
>>> what means 0x21 ??
>>>
>>> and
>>>
>>> am i better try i2c ???
>>>
>>>
>>>
>>> My purpose is writing data to the ov7670 register.
>>>
>>>
>>> Advice please
>>>
>>  --
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