lpcware

Can LPC11xx ignore NACK in I2C, needed for SCCB?

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by Carlitox on Thu Jan 29 09:29:32 MST 2015
Hi all,

I have an LPC11u14 development board with which I'm trying to communicate with an OV7740 camera from OminiVision, which relies on SCCB protocol to comunicate.

I've found in several places online (here, here, and here) that SCCB is basically I2C in which the ACK/NACK (i.e. 9th bit) is replaced by "Don't Care" in SCCB. I've setup all the hardware correctly (VCC, GND, SCL, SDA), and tried running the I2C example code from LPCxpresso. This sample code (where you can look for slave addresses, change between polling and interrupt modes, write to and read from the slaves) works fine with an EEPROM IC. When I try to run the same code with the OV7740 camera, the camera fails to return a low on the 9th bit (i.e. LPC11U14 sees a NACK), and transmission stops.

Is there a way (I could not find any) in which to tell the I2C block to ignore NACK's and just carry on with the transmission? Either registers or just known library functions where I could patch something up without having to re-write the entire driver from scratch.

Thanks in advance,

Carlitox

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