I2C w/ Ti C2000 DSP F2808

JonQC2 · Post by **JonQC2** » Wed May 30, 2007 8:42 am

Hi,

I am having some problems getting a LK204-25-GW to work over an I2C interface. I have attached a screen shot of the slave address. I never receive an ACK, so the I2C module on the dsp does not send the data in its FIFO.

//Setup slave address
I2caRegs.I2CSAR = 0x50;

I2caRegs.I2CDXR = 0xFE; // address
I2caRegs.I2CDXR = 0x58; // clear lcd command

Any ideas??

Does anyone have some code for a C2000 series dsp from Ti??

I have configured the jumpers on the Rev 2 board for I2C

Raquel · Post by **Raquel** » Wed May 30, 2007 9:35 am

Hello John,

Thanks for your post.

Is it possible for you to show the SDA and SCL lines separately? It's just a little hard to see with the two superimposed on each other. It would be nice to see all the parts of the transaction, such as START, and all the 9 clocks (I kind of see 10 in the picture).

Also, when I try to decipher what the lines are doing, it looks like you might be sending a 0xA0 for the address, hence you get a NAK.

Thanks,

JonQC2 · Post by **JonQC2** » Wed May 30, 2007 9:46 am

Hi Raquel,

Attached is another scope capture...

Also, what is the max freq I can run the SCL line at?

Thanks

John

Raquel · Post by **Raquel** » Wed May 30, 2007 11:50 am

Thanks for the scope capture.

This clearly shows that you are addressing with 0xA0. The data is read when the clock line is high. Also, SCL and SDA lines need to idle high.

You can run up to 100 KHz clock. Although I have heard of someone running as fast as 400 KHz.

JonQC2 · Post by **JonQC2** » Wed May 30, 2007 12:17 pm

Thanks!! Works great with the correct address!!