Preliminary Technical Data

ADIS16364

Rev. PrA | Page 9 of 16

BASIC OPERATION

The ADIS16364 is an autonomous sensor system that starts up

after it has a valid power supply voltage and begins producing

inertial measurement data at a sample rate of 819.2 SPS. After

each sample cycle, the sensor data loads into the output registers

and DIO1 pulses, providing 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 hook-up 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 normally found in a configuration register

and used for communicating with the ADIS16364.

SYSTEM

PROCESSOR

SPI MASTER

ADIS16300

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

Figure 9. Electrical Hook-Up 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 ADIS16364 operates as a slave.

Normal mode, SMPL_PRD[7:0] ≤ 0x08.

CPOL = 1

Clock polarity.

CPHA = 1

Clock phase.

MSB-First

Bit sequence.

16-Bit

Shift register/data length.

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 provides the lower byte address for each register, and

Figure 10 provides the generic bit assignments.

UPPER BYTE

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

LOWER BYTE

Figure 10. Output Register Bit Assignments

READING SENSOR DATA

Although the ADIS16364 produces data independently, it oper-

ates as a SPI slave device, which communicates with system

(master) processors using the 16-bit segments displayed in

Figure 11. Individual register reads require two 16-bit sequences.

The first 16-bit sequence provides the read command bit (R/W

= 0) and the target register address (A6 … A0). The second

sequence transmits the register contents (D15 … D0) on the

DOUT line. For example, if DIN = 0x0A00, then the content of

XACCL_OUT shifts 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 config-

uration registers with either a W or R/W. Configuration commands

also use the bit sequence displayed in Figure 12. If the MSB is

equal to 1, the last eight bits (DC7 ... DC0) in the DIN sequence

load into the memory address associated with the address bits

(A5 ... A0). For example, if the DIN = 0xA11F, then 0x1F loads

into Address Location 0x26 (ALM_MAG1, upper byte) at the

conclusion of the data frame.

Most of the registers have a backup location in nonvolatile flash

memory. The master processor must manage the backup

function. Set GLOB_CMD[3] = 1 (DIN = 0xBE01) to execute a

manual flash update (backup) operation, which copies the user

registers into their respective flash memory locations. This

operation takes 50 ms and requires the power supply voltage

to be within the specified limit to complete properly. The

FLASH_CNT register provides a running count of these events

for managing the long-term reliability of the flash memory.

BURST MODE DATA COLLECTION

Burst mode data collection offers a more process-efficient

method for collecting data from the ADIS16364. In 10

sequential data cycles (each separated by one SCLK period), all

nine output registers clock out on DOUT. This sequence starts

when the DIN sequence is 0011 1110 0000 0000 (0x3E00). Next,

the contents of each output register are output from DOUT,

starting with SUPPLY_OUT and ending with AUX_ADC (see

Figure 12). The addressing sequence shown in Table 8 deter-

mines the order of the outputs in burst mode.