HMC6352 Compass interface

Development Boards MicroMod
1

I have the Sparkfun HMC6352 breakout board and the MSP430f160 board.

The I2C generates commands and I get acknowledge bits. But, the data bus is high (open) when I clock data.

I have tried different command sequences with the same result.

I assume that the command sequence is still wrong. Anybody have experience with this device?

2

I am having the same exact problem I think… I use to get an ACK from from the compass when the slave address was sent. I have this logicport view to see the signal happening. For some reason now I am not getting the ACK back but I do get the start bit and the slave address being sent. But it just wont send any other data on the line with what ever I try. You figure anything out yet???

3

Thanks for the response.

No success yet. I have the compass at the end of a long cable. I don’t see any reflections on the line but that could be a contributor. I will shorten it.

I have tried all of the operating modes with and without the A command. There has to be something obvious that is missing.

I will keep trying and post the results. Keep me informed on your progress.

Tom

4

For some reason it didn’t post my last comment. Don’t feel like saying that all again but I think the slave address for the compass is actually 21(hex) for MSP users. I would love to talk about the compass and the MSP… I am using it for a project for school and really need to get it fully functioning. My email is travis.majors@colorado.edu. I have been able to talk to the compass and read ROM and EE. Just haven’t figured out how to get compass readings yet for some reason. :-/

5

Finally got the compass to send back degree data. Put a little digital filtering on it and divided it by 10 to give the range of 0-359. Everything seems to be working smoothly. The key was using 21(hex) as a slave address and setting your transmit or receive bit correctly.

6

Thanks -

I worked with my system for a couple of hours yesterday. Everything works except the read command. I get a no acknowledge to a 043h. The two data bytes have acknowledge bits but the data is FF.

So, are you saying that I use 021h for the read command?

Thanks,

Tom

7

Ya use 21h for the read command and change I2CTCTL &= ~I2CTRX; (makes I2CTRX=0). This will put the MSP in receive mode.

8

I bit bang the I2C with assembly code. So rcv mode is not a problem.

9

Changing the address to 0x21 worked for me. Data sheet says 0x42, but 0x21 works.