HMC5843 Honeywell Microelectronics & Precision Sensors, HMC5843 Datasheet - Page 21

• Manufacturer Part Number: HMC5843
• Description: Magnetic Sensor
• Manufacturer: Honeywell Microelectronics & Precision Sensors

Specifications of HMC5843

• Msl: MSL 3 - 168 Hours
• Sensitivity Range: +/- 10 %
• Sensor Terminals: PCB
• Magnetic Field Max: 4G
• Axis Configuration: Three
• Sensor Output: Digital

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Plymouth, MN 55441
Tel: [phone]
www.honeywell.com/magneticsensors
HMC5843
I2C bus control can be implemented with either hardware logic or in software. Typical hardware designs will release the
SDA and SCL lines as appropriate to allow the slave device to manipulate these lines. In a software implementation, care
must be taken to perform these tasks in code.
OPERATIONAL EXAMPLES
The HMC5843 has a fairly quick stabilization time from no voltage to stable and ready for data retrieval. The nominal 5
milli-seconds with the factory default single measurement mode means that the six Bytes of magnetic data registers
(DXRA, DXRB, DYRA, DYRB, DZRA, and DZRB) are filled with a valid first measurement.
To change the measurement mode to continuous measurement mode, after the 5 milli-second power-up time send the
three bytes:
0x3C 0x02 0x00
This writes the 00 into the second register or mode register to switch from single to continuous measurement mode
setting. With the data rate at the factory default of 10Hz updates (100 milli-seconds interval), a 100 milli-second delay
should be made by the I2C master before querying the HMC5843 data registers for new measurements. To clock out the
new data, send:
0x3D, and clock out DXRA, DXRB, DYRA, DYRB, DZRA, DZRB located in registers 3 through 8. The HMC5843 will
automatically re-point back to register 3 for the next 0x3D query, expected 100 milli-seconds or later.
EXTERNAL CAPACITORS
The two external capacitors should be ceramic type construction with low ESR characteristics. Reservoir capacitor C1 is
nominally 4 .7 micro-farads in capacitance, with the set/reset capacitor C2 nominally 0.22 micro-farads in capacitance.
Low ESR characteristics may not be in many smallest size SMT ceramic capacitors (0402), so be prepared to up-size the
capacitors to gain Low ESR characteristics.
ORDERING INFORMATION
FIND OUT MORE
For more information on Honeywell’s Magnetic Sensors visit us online at www.honeywell.com/magneticsensors or contact
us at 800-323-8295 (763-954-2474 internationally).
The application circuits herein constitute typical usage and interface of Honeywell product. Honeywell does not warranty or assume liability of customer-
designed circuits derived from this description or depiction.
Honeywell reserves the right to make changes to improve reliability, function or design. Honeywell does not assume any liability arising out of the
application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others.
U.S. Patents 4,441,072, 4,533,872, 4,569,742, 4,681,812, 4,847,584 and 6,529,114 apply to the technology described
www.honeywell.com
HMC5843
HMC5843-TR
Ordering Number
3-Axis Digital Compass IC
Tape and Reel 2.5k pieces/reel
Product
Form #900367
September 2008
©2008 Honeywell International Inc.
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