User Manual

ManualsBrandsDigilent ManualsDevelopment Boards & KitsPmod CMPS2: 3-Axis Compass

1300 Henley Court

Pullman, WA 99163

509.334.6306

www.store. digilent.com

Pmod CMPS2™ Reference Manual

Revised July 19, 2017

This manual applies to the Pmod CMPS2 rev. A

DOC#: 410-355

Other product and company names mentioned may be trademarks of their respective owners.

Page 1 of 12

Table of Contents

Table of Contents .................................................................................................................. 1

Overview ............................................................................................................................... 2

1 Specifications ................................................................................................................. 2

1.1 Pinout Table Diagram ....................................................................................................... 3

1.2 Physical Dimensions ......................................................................................................... 3

2 Functional Description ................................................................................................... 3

2.1 Serial Communication ...................................................................................................... 3

2.2 Register Details ................................................................................................................. 3

2.2.1 Data Registers ........................................................................................................... 3

2.2.2 Status Register .......................................................................................................... 4

2.2.3 Internal Control Registers ......................................................................................... 4

2.2.4 Continuous Measurement Mode.............................................................................. 5

2.2.5 Output Resolution Measurement Time .................................................................... 5

2.3 Quick Start ........................................................................................................................ 5

2.4 Applications Information.................................................................................................. 7

2.4.1 Calibration ................................................................................................................. 7

2.4.2 Data Conversion ...................................................................................................... 11

2.5 Timing Diagrams ............................................................................................................. 12

Summary of content (12 pages)

PAGE 1
300 Henley Court Pullman, WA 99163 509.334.6306 www.store. digilent.com Pmod CMPS2™ Reference Manual Revised July 19, 2017 This manual applies to the Pmod CMPS2 rev. A Table of Contents Table of Contents .................................................................................................................. 1 Overview............................................................................................................................... 2 1 2 Specifications .............................
PAGE 2
Pmod CMPS2™ Reference Manual Overview The Digilent Pmod CMPS2 is a 3 axis anisotropic magneto-resistive sensor. With Memsic's MMC34160PJ, the local magnetic field strength in a ±16 Gauss range with a heading accuracy of 1° and up to 0.5 mG of resolution. Features include:           Low noise 3-axis Digital Compass 0.5 mG Field Resolution in ±16 Gauss fields I²C Slave, FAST (≤400 kHz) mode Optional pull-up resistors for SCL and SDA pins ±1° heading accuracy Small PCB size for flexible designs 0.
PAGE 3
Pmod CMPS2™ Reference Manual 1.1 Pinout Table Diagram Header J1 Pin Signal 1 N/C Description Not Connected Header J2 Pin Signal 1 N/C Description Not Connected Jumper JP1 Pin Status SCL Loaded 2 N/C Not Connected 2 N/C Not Connected SCL Unloaded 3 SCL Serial Clock 3 SCL Serial Clock SDA Loaded 4 SDA Serial Data 4 SDA Serial Data SDA Unloaded 5 GND 5 GND 6 VCC Power Supply Ground Power Supply (3.3V) 6 VCC Power Supply Ground Power Supply (3.3V) 1.2 Description 4.
PAGE 4
Pmod CMPS2™ Reference Manual Data Registers addresses 0x00 to 0x05 Address Register Name 0x02 Y out LSB 0x03 Y out MSB 0x04 Z out LSB 0x05 Z out MSB 2.2.
PAGE 5
Pmod CMPS2™ Reference Manual Bit Name RST Bit Number [7] Internal Control 1 Bit Description Software reset bit TEMP-tst ST_XYZ [6] [5] Temp test Selftest check 0¹ 0¹ Z-inhibit Y-inhibit X-inhibit BW1³ [4] [3] [2] [1] Z-inhibit Y-inhibit X-inhibit Bandwidth bit 0¹ 0¹ 0¹ 0¹ BW0³ [0] Bandwidth bit 0¹ Bit Values 0¹ Functional Description Normal Operation, this bit self clears Factory-use register Set this bit an execute TM command, the result can be read as bit ST-XYZ_OK Factory-use register Fa
PAGE 6
Pmod CMPS2™ Reference Manual I2CBegin(0xA0); //device ID 0x30 with a write (0) bit 3. 4. Wait to receive an ACK from the Pmod CMPS2. Send the Internal Control Register 0 (address 0x07) as the register to communicate with I2CWrite(0x07); //address 0x07 corresponds to Control Register 0 5. 6. Wait to receive an ACK from the Pmod CMPS2. Write the command to take a measurement by setting bit 0 high followed by a STOP bit. I2CWrite(0x01); //0x01 initiates a data acquisition 7. 8. Delay at least 7.
PAGE 7
Pmod CMPS2™ Reference Manual I2CReadMultiple(6); //read six bytes, sending an ACK to the slave device betwe en each byte received and a NACK after the last byte 20. Convert the readings into usable data. More details are available in the Data Conversion section. 21. Wait 1/3 of the acquisition time (by default 2.64 ms) before performing another measurement. 2.4 Applications Information The Pmod CMPS2 is an ideal Pmod to use as a compass.
PAGE 8
Pmod CMPS2™ Reference Manual I2CWrite(0x20); //0x20 starts the SET action 14. Wait to receive an ACK from the Pmod CMPS2. 15. Delay at least 1 mS to allow the Pmod CMPS2 to finish the SET action. 16. Provide a START condition and call the device ID with a write bit I2CBegin(0xA0); //device ID 0x30 with a write (0) bit 17. Wait to receive an ACK from the Pmod CMPS2. 18.
PAGE 9
Pmod CMPS2™ Reference Manual I2CBegin(0xA1); //device ID 0x30 with a read (1) bit 32. Wait to receive an ACK from the Pmod CMPS2. 33. Cycle the SCL line to receive the data bits from the X, Y, and Z registers in the SDA line, providing an ACK between each data byte. The Pmod CMPS2 address pointer automatically moves to each consecutive byte. End the communication by sending a NACK followed by a STOP command.
PAGE 10
Pmod CMPS2™ Reference Manual 50. Provide a START condition and call the device ID with a write bit I2CBegin(0xA0); //device ID 0x30 with a write (0) bit 51. Wait to receive an ACK from the Pmod CMPS2. 52. Send the Internal Control Register 0 (address 0x07) as the register to communicate with I2CWrite(0x07); //address 0x07 corresponds to Control Register 0 53. Wait to receive an ACK from the Pmod CMPS2. 54. Write the command to take a measurement by setting bit 0 high followed by a STOP bit.
PAGE 11
Pmod CMPS2™ Reference Manual 67. Cycle the SCL line to receive the data bits from the X, Y, and Z registers in the SDA line, providing an ACK between each data byte. The Pmod CMPS2 address pointer automatically moves to each consecutive byte. End the communication by sending a NACK followed by a STOP command. I2CReadMultiple(6); //read six bytes, sending an ACK to the slave device betwe en each byte received and a NACK after the last byte 68.
PAGE 12
Pmod CMPS2™ Reference Manual    2.5 If D is between 112.5 degrees and 157.5 degrees – South-East If D is between 67.5 degrees and 112.5 degrees – East If D is between 0 degrees and 67.5 degrees – North-East Timing Diagrams An example timing diagram for reading and writing to the Pmod CMPS2 taken from the Memsic datasheet is provided below: When using an external power supply to run the Pmod, be sure to stay within the parameters provided in Specifications. Copyright Digilent, Inc.