TMS320F2808 I2C pull-up resistors

Eduardo Rondon said:

I having problems with the I2C of the 2808, the bit  bb never goes to 0. However in my embedded board i put the pull-up resitors to 5v, this could generate this problem because the the dsp work with vdd of 3.3?

 

I'm sorry, I don't have an answer for  your inquiry on the BB never going to 0.

But you should not have a resistor to 5V connected to the F2808 I/O.

Hello Eduardo,

I have experienced similar problems with the 2808.  I was using the eZdsp development kit from Spectrum Digital.  With the kit, I was trying to communicate to 256K serial I2C EEPROM using the example code I got from TI.  Every time I tried to communicate with the device the Busy Bit would always be stuck.  Are you using the same kit?  I've tried various settings for the serial pull-ups with no change in affect.

Hello,

In fact i know why the bb is always 0.. is because after the device (2808) sends the slave address throught the sda, the slave doesn't send an ack, so for the 2808 is like having a nack, the transferts is stop and the stop bit is cleared... In that case the only way to cleared the bb bit, is to activate the nack interruption and reset the peripherial when a nack interruption occurs, and reactivate the peripherial after that... 

However the problem is why the slave is no responding to his address, in my case i don't know. I guessed it was because the voltage level difference (2808  3.3v and slave 5v) so i put a buffer (an 74LVC4245) but it still doesnt work. 

By the way im not using the eZdsp development kit, i'm using a board that i made...