I have tried to use the lowspeedread and lowspeed write in LabVIEW NXT Toolkits with pcf8574 by I2C mode.
It is ok when I used write-command to setup i/o output.(Fig1)
But when I tried to read i/o input status. If I set the response byte is 1 in lowspeedwrite, this vi will sent the 0x21 write command before read data.(Fig2)
I don't understand why this vi behavior. If the response byte is zero, and write command sent more one 0xFF btye like in uC I2C programming. The date we recevied will be correct ilke Fig3.but NXT will not receive dat in buffer. XD
I want to trace the vi, but it need password. ....Orz .Otherwise , I had used the NXT-G for pcf8574 in Logo MINDSTORM. I sure it is software problem in LabVIEW NXT toolkits.
