I'm having problems programming HMR3300 compass and display it, HMR3300 compass works by sending a command(command *H) and then it will start response and feedback headings (response format eg 126.5 ) . I'm planning to display the compass's readings continuously as it turns on the Hitachi LCD display screen. However, I'm unable to display the readings on the LCD screen. I hope someone can give me a sample code to guide me. Thanks.
Here is a link for the HMR3300 datasheet.
The HMR3200/HMR3300 will begin sending ASCII characters immediately after the initialization routine ends and the LED extinguishes. The first line of text will be the model number of the compass and the internal firmware revision number.
Are you receiving that string when you power up the compass? If not, your wiring or logic is probably faulty.
According to the datasheet you don't need to send *H to get the heading. By default it should be sending you the heading eight times a second!