Data Sheet
ADIS16367
THEORY OF OPERATION
BASIC OPERATION
The user registers provide addressing for all input/output
The ADIS16367 is an autonomous sensor system that starts up
after it has a valid power supply voltage and begins producing
inertial measurement data at the factory default sample rate
setting of 819.2 SPS. After each sample cycle, the sensor data is
operations on the SPI interface. Each 16-bit register has two
7-bit addresses: one for its upper byte and one for its lower byte.
Table 8 lists the lower byte address for each register, and Figure 10
shows the generic bit assignments.
loaded into the output registers, and DIO1 pulses high, which
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
provides a new data-ready control signal for driving system-
UPPER BYTE
LOWER BYTE
level interrupt service routines. In a typical system, a master
Figure 10. Generic Register Bit Assignments
processor accesses the output data registers through the SPI
interface, using the connection diagram shown in Figure 9.
Table 6 provides a generic functional description for each pin
on the master processor. Table 7 describes the typical master
processor settings that are normally found in a configuration
register and used for communicating with the ADIS16367.
E I/O LINES ARE COMPATIBLE WITH
3.3V OR 5V LOGIC LEVELS
5V
VDD
SYSTEM
T PROCESSOR
SPI MASTER
SS
SCLK
10 11 12
6 CS ADIS16367
3 SCLK
SPI SLAVE
MOSI
5 DIN
E MISO
4 DOUT
IRQ
7 DIO1
13 14 15
L Figure 9. Electrical Connection Diagram
Table 6. Generic Master Processor Pin Names and Functions
O Pin Name
Function
SS
Slave select
SCLK
Serial clock
S MOSI
Master output, slave input
MISO
Master input, slave output
IRQ
Interrupt request
B Table 7. Generic Master Processor SPI Settings
Processor Setting Description
Master
The ADIS16367 operates as a slave
SCLK Rate ≤ 2 MHz1 Normal mode, SMPL_PRD[7:0] ≤ 0x09
O SPI Mode 3
CPOL = 1 (polarity), CPHA = 1 (phase)
READING SENSOR DATA
Although the ADIS16367 produces data independently, it
operates as a SPI slave device that communicates with system
(master) processors using the 16-bit segments displayed in
Figure 11. Individual register reads require two of these 16-bit
sequences. The first 16-bit sequence contains the read command
bit (R/W = 0) and the target register address (A6 to A0); the last
eight bits are “don’t care” bits when requesting a read. The second
16-bit sequence transmits the register contents (D15 to D0) on
the DOUT line. For example, if DIN = 0x0A00, the contents of
XACCL_OUT are shifted out on the DOUT line during the
next 16-bit sequence.
The SPI operates in full-duplex mode, which means that the master
processor can read the output data from DOUT while using the
same SCLK pulses to transmit the next target address on DIN.
DEVICE CONFIGURATION
The user register memory map (see Table 8) identifies
configuration registers with either a W or R/W. Configuration
commands also use the bit sequence shown in Figure 11. If the
MSB = 1, the last eight bits (DC7 to DC0) in the DIN sequence
are loaded into the memory address associated with the address
bits (A6 to A0). For example, if DIN = 0xA11F, 0x1F is loaded
into Address 0x21 (XACCL_OFF, upper byte) at the conclusion
of the data frame.
The master processor initiates the backup function by setting
GLOB_CMD[3] = 1 (DIN = 0xBE08). This command copies
the user registers into their assigned flash memory locations
and requires the power supply to stay within its normal operating
range for the entire 50 ms process. The FLASH_CNT register
provides a running count of these events for monitoring the
MSB First Mode
Bit sequence
long-term reliability of the flash memory.
16-Bit Mode
Shift register/data length
1 For burst read, SCLK rate ≤ 1 MHz. For low power mode, SCLK rate ≤ 300 kHz.
CS
SCLK
DIN
DOUT
R/W A6 A5 A4 A3 A2 A1 A0 DC7 DC6 DC5 DC4 DC3 DC2 DC1 DC0
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
R/W A6 A5
D15 D14 D13
NOTES
1. THE DOUT BIT PATTERN REFLECTS THE ENTIRE CONTENTS OF THE REGISTER IDENTIFIED BY [A6:A0] AND [R/W = 0]
IN THE PREVIOUS SEQUENCE.
2. IF R/W = 1 DURING THE PREVIOUS SEQUENCE, DOUT IS NOT DEFINED.
Figure 11. SPI Communication Bit Sequence
Rev. B | Page 9 of 20