Hello again! I have 3 devices on an I2C bus, SFR08, HMC6352, TMP102 all displaying on a 20x4 display..........or so I thought? Program compiles without error, (and the SRF08 and HMC6352 work fine) but when I add the TMP102 onto the I2C bus the data gets clamped. Do I need the same value (10k) pull resistors on the TMP102 as I have on the HMC6352? The TMP102 data sheet just says the SDA and SCL lines need them so I put in 5k resistors, should they be 10k?

Thank You.

Lets solve this before I start asking about the HMC6352 output data!

You only need 1 set of resistors on the I2C lines. If you keep placing more in parallel, eventually the load impedance will be too small. However since you are using fairly large resistors apparently that should work fine. How do you mean the data gets clamped?

Yep, I agree got my old books out and realised I'd just put 2 resistors in parallel for no reason, so I'll modify my circuit tonight.....Just done that and the TMP102 is definately fubar so best to replace it!

What I meant by clamped was that the values I saw being displayed on the LCD for both devices had the same numeric value which is not representative of what I usually see. Without the TMP102 being connected on the I2C bus they work fine. So guess the fubar TMP102 was pulling up/down the SDA/SCL lines, as the SRF08 and HMC6352 devices were both displaying 32564

My question regarding the HMC6352 is that it displays ten numeric characters, the last five being all zero values. I'm trying to understand Aaron's code so I can modify it to just return 5 characters, like "Heading 321.4 deg" or "Heading 009.3 deg"

Thank You