2009-12-15 20:56:59     SCCB Help!

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2009-12-15 20:56:59     SCCB Help!

尔文 罗 (CHINA)

Message: 83542   

 

Hi

 

    I have set SCCB bit in TWI_CONTROL register when i2c_bfin_twi do probe, but i still can't read register exactly from OV7725.

 

    I used an oscilloscope to see timing when driver read register, 2-Phase Write Transmisson cycle seen exactly, but after sent ID Addres in 2-Phase Read Transmission Cycle the SDA line had been pulled down always, and the driver was waiting always, just looked like dead.

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2009-12-15 22:02:05     Re: SCCB Help!

Sonic Zhang (CHINA)

Message: 83543   

 

The i2c-bfin-twi driver doesn't support SCCB compatibility mode and has never run any testing against SCCB devices.

 

What did you change to this driver?

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2009-12-15 22:28:45     Re: SCCB Help!

尔文 罗 (CHINA)

Message: 83545   

 

TWI_CONTROL register have a SCCB bit, so i just set this bit in function i2c_bfin_twi_probe.

 

Read register test is in my OV7725 driver instead of i2c_bfin_twi.

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2009-12-16 00:13:07     Re: SCCB Help!

Sonic Zhang (CHINA)

Message: 83547   

 

Then, witch i2c api did you use in your test application? transfer or smbus?

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2009-12-16 01:28:41     Re: SCCB Help!

尔文 罗 (CHINA)

Message: 83551   

 

write register use i2c_smbus_read_byte_data , and read register use i2c_smbus_write_byte_data.

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2009-12-16 02:45:53     Re: SCCB Help!

Sonic Zhang (CHINA)

Message: 83553   

 

Are you sure the smbus protocol compatible with SCCB protocol with SCCB bit set?

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2009-12-16 05:20:13     Re: SCCB Help!

尔文 罗 (CHINA)

Message: 83596   

 

Yes, I am sure.

 

I separated 2-Phase Write Cycle and 2-Phase Read Cycle when readed register,  and i can read register value exactly now

 

But i am really confuse also, i found the SCCB bit didn't matter .

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