
ADIS16360/ADIS16365
Rev. B | Page 9 of 20
THEORY OF OPERATION
BASIC OPERATION
The ADIS16360/ADIS16365 are autonomous sensor systems
that start up after they have a valid power supply voltage and
begin producing inertial measurement data at the factory default
sample rate setting of 819.2 SPS. After each sample cycle, the
sensor data is loaded into the output registers, and DIO1 pulses
high, which provides a new data ready control signal for driving
system-level interrupt service routines. In a typical system, a
master 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 ADIS16360/ADIS16365.
SYSTEM
PROCESSOR
SPI MASTER ADIS16360/
ADIS16365
SPI SLAVE
SCLK
CS
DIN
DOUT
SCLK
SS
MOSI
MISO
5V
IRQ DIO1
VDD I/O LINES ARE COMPATIBLE WITH
3.3V OR 5V LOGIC LEVELS
10
6
3
5
4
7
11 12
13 14 15
7570-009
Figure 9. Electrical Connection Diagram
Table 6. Generic Master Processor Pin Names and Functions
Pin Name Function
SS Slave select
IRQ Interrupt request
MOSI Master output, slave input
MISO Master input, slave output
SCLK Serial clock
Table 7. Generic Master Processor SPI Settings
Processor Setting Description
Master The ADIS16360/ADIS16365 operate as slaves
SCLK Rate ≤ 2 MHz1Normal mode, SMPL_PRD[7:0] ≤ 0x09
SPI Mode 3 CPOL = 1 (polarity), CPHA = 1 (phase)
MSB First Mode Bit sequence
16-Bit Mode Shift register/data length
1For burst read, SCLK rate ≤ 1 MHz. For low power mode, SCLK rate ≤ 300 kHz.
The user registers provide addressing for all input/output
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.
UPPER BYTE
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
LOWER BYTE
07570-010
Figure 10. Generic Register Bit Assignments
READING SENSOR DATA
Although the ADIS16360/ADIS16365 produce data indepen-
dently, they operate as SPI slave devices that communicate 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 configu-
ration 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 = 0xBE04). 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
long-term reliability of the flash memory.
7570-011
R/W R/W
A6 A5 A4 A3 A2 A1 A0 DC7 DC6 DC5 DC4 DC3 DC2 DC1 DC0
D0D1D2D3D4D5D6D7D8D9D10D11D12D13D14D15
CS
SCLK
DIN
DOUT
A6 A5
D13D14D15
NOTES
1. DOUT BITS ARE PRODUCED ONLY WHEN THE PREVIOUS 16-BIT DIN SEQUENCE STARTS WITH R/W = 0.
Figure 11. SPI Communication Bit Sequence