Currently developing a UVC Camera system using Omnivison Camerachips.

Omnivison use their SCCB 2-wire interface which unfortunately does not privide an ACK bit for the 9th bit, instead the bit is identified as "Don't Care"

Is there a workaround to force the API firmware to ignore the ACK bit?

 If that is the case then I think it is better to implement I2C using two GPIOs (bit banging).

Can you update the SDK so that it supports the Omnivision SCCB interface ?... We really dont want to do the old fashioned I2C bitbanging !      OR can you include a parameter in the I2C API's to ignore the ACK ?

Hi Logicland,

Have u been able to get the SCCB bit-banging code to successfully work with ur Omnivision camera? We are not...pls share the code if u got success. We are using OV9650 camera.

Thanks,

sriraam

After hooking up an OmniVision OV5620 to test the comms we found it worked OK, just like any other I2C device.

Anyway here is the code:-

/* Functions for OmniVision Chips */
void sccb_read_reg(uint8_t reg, uint8_t *data)
{
    CyU3PReturnStatus_t apiRetStatus;
    CyU3PI2cPreamble_t preamble;
    preamble.buffer[0] = 0x60;
    preamble.buffer[1] = reg;
    preamble.buffer[2] = 0x61;
    preamble.length = 3;
    preamble.ctrlMask = 1 << 1;
    apiRetStatus = CyU3PI2cReceiveBytes(&preamble, data, 1, 0);
    if(apiRetStatus != CY_U3P_SUCCESS){
        CyU3PDebugPrint(8, "i2c Receive Failed, Error Code = %d\n\r", apiRetStatus);
    }else{
        CyU3PDebugPrint(8, "i2c Receive Data = %x,%x\n\r", reg, *data);
    }
}

void sccb_write_reg(uint8_t reg, uint8_t *data)
{
    CyU3PReturnStatus_t apiRetStatus;
    CyU3PI2cPreamble_t preamble;
    preamble.buffer[0] = 0x60;
    preamble.buffer[1] = reg;
    preamble.length = 2;
    preamble.ctrlMask = 0 << 2;
    apiRetStatus = CyU3PI2cTransmitBytes(&preamble, data, 1, 0);
    if(apiRetStatus != CY_U3P_SUCCESS){

        CyU3PDebugPrint(8, "i2c Send Failed, Error Code = %d\n\r", apiRetStatus);
    }else{
        CyU3PDebugPrint(8, "i2c Send Data = %x,%x\n\r", reg, *data);
    }
}

Actually I2C source file is opened in the SDKv1.2.

So I think you should be able to modify the I2C APIs according to your requirement. Please let me know if it is not possible.

Thanks,

sai krishna.

Hi Logicland,

Thanks for your code snippet. Fortunately our bit banging code also worked after debugging.

Hi Saikrishna,

Thanks for your reply.  I dont find any 'C' source file for I2C API's in the following SDK 1.2 instalation location:

C:\Cypress\EZ-USB FX3 SDK\1.2

Regds,

Sriraam

Hi Sriram,

In the SDK installation files, look for lpp_source folder in firmware folder.

You can find the i2c code in cyu3i2c.c file.

Please let me know if you face any trouble in finding it.

Thanks,

sai krishna.

Thanks Krishna...we found it in the path you specified.

Rgds, Sriraam