Email: Password: Remember Me | Create Account (Free)


 

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
Michael Karas
02/01/10 09:02
Read: 207 times
Beaverton Or
USA


 		 #172838 - Pullup resistor size...
Responding to: Anil Sangani's previous message
There are often times that a pull-up resistor of 10K on an I2C bus is too large of value. You should check the SCL and SDA signalling on an oscilloscope to make sure that your protocol is not being upset by too show of risetime on the bus lines.

At the same time that you have the scope connected up you should attempt to verify the serial transmission to ensure that every part of the protocol is correct and that the timing is valid. Do also check that the RTC chip is sending an ACK in the 9th SCL time slot of the transmission sequence.

Michael Karas


List of 7 messages in thread
TopicAuthorDate
problem with ds1307 andi2c      Anil Sangani      02/01/10 06:04      
   Did you provide a resistor...        Michael Karas      02/01/10 08:45      
      pull up on ds1307 sqwout      Anil Sangani      02/03/10 23:52      
   Pullup resistor size...      Michael Karas      02/01/10 09:02      
   clock halt bit?      John Myers      02/01/10 16:31      
      ds1307 and i2c problem      Anil Sangani      02/02/10 00:57      
         A 10MHz analog scope is fine for 100kHz i2c      David Prentice      02/02/10 02:25      

Back to Subject List