Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

PCA9955 LED driver interface problem with ATmega128

Status
Not open for further replies.
S

sujan_014

Newbie level 6
Joined
Mar 13, 2014
Messages
11
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
96
I am trying to interface PCA9955 with ATmega128. I connected address pin A0, A1, A2 and A3 to ground and used device address 0xC0 to communicate using I2C. The I2C code is verified as I have used the same code to communicate with other I2C device.. Despite this, PCA9955 does not acknowledge when device address, register address or data is sent. Can any one tell me what is problem here ?
ckt_t.jpg

This is my circuit.
 

Can you probe on the SCL & SDA lines and verify it is toggling? What speed I2C clock is operating? Try to reduce the clock and try.
 

Yes, the SCL and SDA lines are also toggling when data was sent. I checked through oscilloscope. The I2C speed is 1000Hz. I think that the problem lies in this hardware but so far I don't know where it is !
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top