Deine I2C Leseroutine sieht etwas komisch aus. Was ist "I2Cwbyte &H1" ?

Versuchs doch mal so:

Dim Highb as Byte
Dim Midb as Byte
Dim Lowb as Byte
Dim Wert as Word at Highb Overlay

i2cstart
i2cwbyte &H91
i2crbyte Highb, Ack
i2crbyte Midb, Ack
i2crbyte Lowb, Nack
i2cstop

Lcd "Wert: " , Wert