SMBus using Silicon Labs C8051F560

Question

I am trying to communicate an arduino with a Silabs F560 Toolstick Daughter Card.

On Arduino (Master)

I have loaded the i2c scanner program from http://playground.arduino.cc/Main/I2cScanner which basically pings all possible address (0x00 to 0x7F) on the bus trying to get an ACK.

On C8051F560 (Slave)

I have loaded the example Slave code given by Silicon Labs of address 0x78. I have changed the SMBus frequency to 100000 (since Arduino works on 100kHz)

The Arduino was not able to recognise it on the bus. I have tried pull-up resistors of different combinations 3.3k, 6.6k, 10k ohms. That didn't make any difference.

When I tried to analyse the bus with a logic analyser, the SiLabs MCU was disrupting the SCL driven by Arduino.

I think an example code given by a manufacturer should work fine.

Is there anything I am missing ? or is it the H/W that is damaged ?

Answer 1

The problem was with the F560 DC where the Pin P0.0 (VREF) is connected to GND by default. It was specified in the schematic of the F560DC. I hav changed the pins used by the SMBus peripheral to P0.2 and P0.3 and it all worked just fine.