Datasheet ADIS16136 (Analog Devices) - 9

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ADIS16136 Data Sheet THEORY OF OPERATION
The ADIS16136 is an autonomous system that requires no user
Table 7. Generic Master Processor SPI Settings
initialization. As soon as it has a valid power supply, it initializes
Processor Setting Description
and starts sampling, processing, and loading sensor data into Master ADIS16136 operates as a slave the output registers. After each sample cycle concludes, DIO1 SCLK Rate ≤ 2 MHz Maximum serial clock rate pulses high. The SPI interface enables simple integration with SPI Mode 3 CPOL = 1 (polarity), CPHA = 1 (phase) many embedded processor platforms, as shown in Figure 10 MSB First Mode Bit sequence (electrical connection) and Table 6 (processor pin names and 16-Bit Mode Shift register/data length functions).
I/O LINES ARE COMPATIBLE WITH READING SENSOR DATA 5V 3.3V OR 5V LOGIC LEVELS VDD
A single register read requires two 16-bit SPI cycles. The first
10 11 12
cycle requests the contents of a register using the bit assignments
SYSTEM PROCESSOR SS 6 CS ADIS16136
in Figure 13. Then, the register contents follow on DOUT during
SPI MASTER 3
the second sequence. Figure 11 includes three single register reads
SCLK SCLK MOSI 5 DIN
in succession. In this example, the process starts with Pin 5,
MISO 4 DOUT
DIN = 0x0600, to request the contents of the GYRO_OUT
IRQ 7 DIO1
register and fol ows with 0x0400 to request the contents of the GYRO_OUT2 register and with 0x0200 to request the contents
13 14 15
010 of the TEMP_OUT register. Full duplex operation enables pro- 10249- cessors to use the same 16-bit SPI cycle to read data from DOUT Figure 10. Electrical Connection Diagram while requesting the next set of data on the DIN pin. Figure 12
Table 6. Generic Master Processor Pin Names and Functions
provides an example of the four SPI signals when reading GYRO_OUT in a repeating pattern.
Pin Name Function
SS Slave select
DIN 0x0600 0x0400 0x0200
1 IRQ Interrupt request 1 0
DOUT GYRO_OUT GYRO_OUT2 TEMP_OUT
MOSI Master output, slave input 10249- MISO Master input, slave output Figure 11. SPI Read Example SCLK Serial clock
CS
The ADIS16136 SPI interface supports full duplex serial
SCLK
communication (simultaneous transmit and receive) and uses
DIN DIN = 0000 0110 0000 0000 = 0x0600
the bit sequence shown in Figure 13. Table 7 provides a list of the most common settings that require attention to initialize a
DOUT
012 processor serial port for the ADIS16136 SPI interface.
DOUT = 1111 1001 1101 1010 = 0xF9DA = –1574 LSBs = –29.765°/sec
10249- Figure 12. SPI Read Example, Second 16-Bit Sequence
CS SCLK DIN R/W R/W A6 A5 A4 A3 A2 A1 A0 DC7 DC6 DC5 DC4 DC3 DC2 DC1 DC0 A6 A5 DOUT D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 D15 D14 D13 NOTES 1. DOUT BITS ARE PRODUCED ONLY WHEN THE PREVIOUS 16-BIT DIN SEQUENCE STARTS WITH R/W = 0.
013
2. WHEN CS IS HIGH, DOUT IS IN A THREE-STATE, HIGH-IMPEDANCE MODE, WHICH ALLOWS MULTIFUNCTIONAL USE OF THE LINE FOR OTHER DEVICES.
10249- Figure 13. SPI Communication Bit Sequence Rev. D | Page 8 of 20 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS TIMING SPECIFICATIONS Timing Diagrams ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION READING SENSOR DATA OUTPUT DATA REGISTERS Rotation Rate (Gyroscope) Internal Temperature DEVICE CONFIGURATION Dual Memory Structure USER REGISTERS DIGITAL PROCESSING CONFIGURATION INTERNAL SAMPLE RATE INPUT CLOCK CONFIGURATION DIGITAL FILTERING AVERAGING/DECIMATION FILTER CALIBRATION AUTOMATIC BIAS CORRECTION (AUTONULL) MANUAL BIAS CORRECTION Restoring Factory Calibration ALARMS STATIC ALARM USE DYNAMIC ALARM USE ALARM REPORTING Alarm Example SYSTEM CONTROLS GLOBAL COMMANDS Software Reset MEMORY MANAGEMENT Checksum Test GENERAL-PURPOSE INPUT/OUTPUT Data Ready Input/Output Indicator Example Input/Output Configuration AUTOMATIC SELF TEST POWER MANAGEMENT STATUS PRODUCT IDENTIFICATION APPLICATIONS INFORMATION POWER SUPPLY CONSIDERATIONS PROTOTYPE INTERFACE BOARD INSTALLATION TIPS PACKAGING AND ORDERING INFORMATION OUTLINE DIMENSIONS ORDERING GUIDE