Only get NACK from CDC913E

Gerhard Kreuzer

Hi,

I tried to communicate with the CDC913E, but only get NACK.

I observed the I2C on the EVM and than I want to use my own Controller. Signals looking good, I guess, Speed is the same but ....

I include a shot of my signals, any idea?

Thanks for helping.

With best regards

Gerhard

over 10 years ago

0 Gabe Ayala over 10 years ago

TI__Genius 10320 points

Hi Gerhard,

Has the I2C address been modified in the EEPROM at any stage? If you are unsure, try addressing the 4 combinations of A1 and A0 of the I2C address from 0x0 to 0x3.

Gabe

0 Gerhard Kreuzer over 10 years ago in reply to Gabe Ayala

Expert 2630 points

Hi,

no, never wrote to the EEPROM, and after inserting the Jumpers again, the chip responds to 65 with ACK.

I have to shots, where is the difference?

With best regards

Gerhard

Original signals from EVM.

Connected to a Atmel XPlaines SAM4n board.

0 Gabe Ayala over 10 years ago in reply to Gerhard Kreuzer

TI__Genius 10320 points

Hi Gerhard,

Thanks for the scope shots. If you note on the falling edge of the first clock pulse, the data is transitioning, possibly violating t_h{SDA}. Is there a way to delay this transition?

Gabe

Clock & timing

Clock & timing forum

Only get NACK from CDC913E