HM55B Compass Problems

bdrew7

I am using a HM55B compass module in an autonomous boat application to backup the gps track data while the boat is moving very slowly and the gps track data becomes ambiguous.

When I run the compass calibration and test software alone in slot 0 of the bs2p24, everything works well!· I understand the cal software is putting 21 bytes of data into eeprom from 0 to 20.· (Is that cal data permanent, if nothing writes over it?· That is my assumption.)

My application software runs seperate programs in five slots, such as initializaiton, motor control, navigation, reporting, and the HM55B software.· None of the other slot programs are accessing the eeprom data at 0.· When I run the application, the compass output data· which is put into a register of·an ·um-FPU 3, varies so slightly, no matter the orientation of the compass.· But again, if I run the HM55B software alone in slot 0 doing exactly the same code, it works perfectly.

Can anyone offer suggestions?· I will be glad to share the code.· What am I missing??

Thanks.
Bernard

Mike Green

It's impossible to make useful suggestions until we can see the code. Post it (as attachments to a message ... not cut and paste).

bdrew7

Here is the zip file of the code.

Thanks.
Bernard

bdrew7

I think my problem is the compass cal data is at 0 in the slot 0 2k of the eeprom.

bdrew7

Calibrated the compass in slot 5 and it works great.

Thanks.

Bernard