Reading problem - PCF8575

Mayer,

I've notified the correct application engineer and you should receive a response shortly.

Hello Mayer,

Can you tell me what you are seeing on the SDA data line when you request for the values of the ports?
How do you know that one port is working but the other is not?

Best,
Michael

Hello Michael,

When I  do a "read" from ports I saw on

P0 = 0x00

P1 = 0xFF

I know  what is on the P0  is responding to my input

and the second port do not change  stay "1"

but on the fluke  I saw the voltage rise up and go down

and also the INT pin response to input changes

but in the reading of the MCU  I don't "see" it

Thanks

Mayer

Hello,

It's seem's there were an acknowledge problem from the master (MCU) to slave (PCF8575)
So My MCU read the first port P0 and with the P1 had a problem
fixed the acknowledge problem and now can read the second port P1 also

SDATA = LOW;    // Master (MCU) send ACK to slave (PCF8575)
SCLK    = HIGH;
SCLK    = LOW;
SDATA = HIGH;

Mayer

Mayer,

Glad you were able to figure it out. 
Please feel free to let me know if you have any further questions.

Best,
Michael