CHIMU User Manual Rev F.
Table of Contents
Contents
1. Introduction ................................................................................................................................5
1.1 Limitations ..........................................................................................................................5
1.1.1 Rate limits.....................................................................................................................5
1.1.2 Acceleration limits.........................................................................................................5
1.1.3 Magnetic field limits.......................................................................................................5
1.1.4 BIT and User Responsibility..........................................................................................5
1.2 Theory of Operation............................................................................................................6
1.2.1 Startup Conditions ........................................................................................................6
1.2.2 Dynamic Operation –Centripetal Acceleration..............................................................7
1.3 Modes of Operation ............................................................................................................7
2. Specifications and Characteristics..............................................................................................8
2.1 Performance Specifications ................................................................................................8
2.2 Electrical Characteristics ....................................................................................................9
2.3 Absolute Maximum Ratings ................................................................................................9
2.4 Mechanical and Pin Assignments .....................................................................................10
2.4.1 Dimensions.................................................................................................................10
2.4.2 Recommended Connectors ........................................................................................10
2.4.3 Coordinate System and Orientation ............................................................................11
2.4.4 Pin Assignments .........................................................................................................12
3. Hardware Integration................................................................................................................14
3.1 Power ...............................................................................................................................14
3.1.1 Input Power ................................................................................................................14
3.1.2 Output Power..............................................................................................................14
3.2 Special Interface Pins .......................................................................................................14
3.2.1 External Speed Select –Pin 3 –DIO_1 ......................................................................14
3.2.2 Com Select –Pin 4 - SSEL .........................................................................................14
3.2.3 Special –Pin 11 –ISP ................................................................................................15
3.2.4 Speed Indicator –Pin 18 –ANA1................................................................................15
3.3 Communication.................................................................................................................15
3.3.1 UART..........................................................................................................................15
3.3.2 SPI Bus.......................................................................................................................15
3.4 Feedback LED..................................................................................................................15
4. Software Interface ....................................................................................................................16
4.1 Basic Message Structure..................................................................................................16
4.1.1 Message format ..........................................................................................................16
4.1.2 Number Formats.........................................................................................................16
4.1.3 CRC Checksum Code.................................................................................................17
5. Input Message Details..............................................................................................................18
5.1 Input Message –Device ID IS Required! ..........................................................................18
5.2 Input Message Summary..................................................................................................18
5.2.1 PING (ID 0x00) ...........................................................................................................19
5.2.2 BIAS AND SCALEFACTOR (ID 0x01) ........................................................................20
5.2.3 DAC MODE (ID 0x02).................................................................................................21
Note that in CHIMU –J and later versions, there are no native DAC voltage outputs. A separate
I2C device must be used to create voltage outputs. .................................................................21
5.2.4 ACCELEROMETER CALIBRATION MODE (ID 0x03) ................................................22
5.2.5 MAGNETOMETER CALIBRATION MODE (ID 0x04)..................................................23
5.2.6 TEMPERATURE CALIBRATION MODE (ID 0x05) .....................................................24
5.2.7 CONFIGURATION CLEAR (ID 0x06) .........................................................................25
