I2C problem


I have a problem with the I2C protocol. Iuse the I/O in I2C mode (AT*E2I2C =1) and I2C(0) 100khz clock. When I want addressed an PCF8574 (Write mode) I make the AT command With the address 0x42 (chip address) and 0xF0 for the data : I2w(0x42,1,0xF0,&ack).
But, on the scope I can see the protocol I2C on the PIN SDA and SDL. There is:
Start condition OK
Address chip 0x42 OK
ACk send by the PCF8574 OK
The data send by the GR64 are wrong, the SDA pin don’t sent 0xF0 but 0xE5 and I try to send 0x11 and the GR64 send 0xF0, 0x12 GR64 send 0x9F. It’s very strange, it’s no logic. I don’t understand.

I use an GR64 R4A and M2MPower IDE 1.1.3.


Hi marc,

Please note that firmware R4C is available, i recommand you to request it to your distributor.


but i called my distributor and they don’t know the R4C. I donwloaded the R4B version on the web site wavecom.I find it on a another web site.