k0fei

I will try the custom.ufd in the thread above, but it sounds like it is going to fix it.  Hopefully the Netduino folks will include your fix in the next release - or at least add a bug to their list about I2C problems.  Thanks for pointing me to what looks like a solution.

I am hooked up to the right pins - SCL and SDA.  I actually have 3 devices on that bus - the TMP100, a DS1307 and a MCP2301 port expander.  I am using 10K pull-ups.  I'll write a test program using the SoftwareI2C code.  My development code is using the SofwareI2CBus and some hacks so I can multi-thread for the devices (as well as the bug fix I posted on another thread).

The Logic 16 is indeed connected to the SCL and SDA pins.  I see the data under the SoftwareI2C (that is how I found that SoftwareI2CBus was sending an ACK not a NAK on the last byte to be read from a slave), but no data at all - even an address - under hardware I2C.  I tried the same test program on a brand new out of the box Netduino Plus 2 fresh from Mouser - still no luck.  I was hoping someone could tell me what I messed up in my test program.

There is a bug in the SoftwareI2CBus module.  Where it calls SoftwareI2C receive, the first parameter needs to be false if it is receiving the last byte of data from a slave.  I2C protocol says the master must send a NAK to the slave on the last byte of data from the slave to tell it that is all the data it is expecting.

Thanks Chris.  I am talking to 8 devices, but doing my own select before starting a transfer and strobing in the data after the transfer.  After a transfer I would like to clock to go low and stay low between transfers.  I suppose I could put an inverter in the hardware, but hoped there was a way to do it in software.

By the say, how do you debug the firmware.  I would be willing to give it a go, especially to fix the I2C driver.  Emulating the I2C bus in software is not ideal.

Frank

I have firmware 4.2.2.2 on brand new Netduino Plus 2 boards.  The SPI clock line stays high during idle times.  I have tried changing the parameter to tell it to stay low, but it has no effect.  Any suggestions?

Thanks - Frank