ADIS16135

Rev. 0 | Page 9 of 20

OUTPUT DATA REGISTERS

Table 8. Output Data Register Formats

Register

Address

Measurement

TEMP_OUT

0x02

Internal temperature

GYRO_OUT2

0x04

Gyroscope, lower 16 bits

GYRO_OUT

0x06

Gyroscope, upper 16 bits

Rotation Rate (Gyroscope)

GYRO_OUT is the primary register for gyroscope output data

and uses 16-bit twos complement format for its data. Table 9

provides the numerical format, and Table 10 provides several

examples for converting digital data into °/sec.

Table 9. GYRO_OUT Bit Descriptions

Bits

Description

[15:0]

Gyroscope data; twos complement,

0.0125°/sec per LSB, 0°/sec = 0x0000

Table 10. GYRO_OUT, Twos Complement Format

Rotation Rate

Decimal

Hex

Binary

+300°/sec

+24,000

0x5DC0

0101 1101 1100 0000

+0.025°/sec

+2

0x0002

0000 0000 0000 0010

+0.0125°/sec

+1

0x0001

0000 0000 0000 0001

0°/sec

0

0x0000

0000 0000 0000 0000

−0.0125°/sec

−1

0xFFFF

1111 1111 1111 1111

−0.025°/sec

−2

0xFFFE

1111 1111 1111 1110

−300°/sec

−24,000

0xA240

1010 0010 0100 0000

The GYRO_OUT2 register (see Table 11) captures the bit growth

associated with the decimation filter shown in Figure 18, using

a MSB-justified format. The bit growth starts with the MSB

(GYRO_OUT2[15]), is equal to the decimation rate setting in

DEC_RATE[4:0] (see Table 18), and grows in the LSB direction

as the decimation rate increases. See Figure 14 for more details.

Table 11. GYRO_OUT2 Bit Descriptions

Bits

Description

[15:0]

Rotation rate data; resolution enhancement bits

GYROSCOPE DATA

NOT USED

D

15

0 15

0

D = DEC_RATE[4:0]

BIT WEIGHT =

0.0125

LSB = GYRO_OUT2[16-D]

°/sec

LSB

GYRO_OUT

GYRO_OUT2

Figure 14. Gyroscope Output Format, DEC_RATE[4:0] > 0

Internal Temperature

The TEMP_OUT register (see Table 12) provides an internal

temperature measurement that can be useful for observing

relative temperature changes in the environment. Table 13

provides several coding examples for converting the 16-bit

twos complement number into units for temperature (°C).

Table 12. TEMP_OUT Bit Descriptions

Bits

Description

[15:0]

Temperature data; twos complement, 0.058°C per LSB,

0°C = 0x0000

Table 13. Temperature, Twos Complement Format

Temperature

Decimal

Hex

Binary

+105°C

+1810

0x712

0000 0111 0001 0010

+0.116°C

+2

0x0002

0000 0000 0000 0010

+0.058°C

+1

0x0001

0000 0000 0000 0001

0°C

0

0x0000

0000 0000 0000 0000

−0.058°C

−1

0xFFFF

1111 1111 1111 1111

−0.116°C

−2

0xFFFE

1111 1111 1111 1110

−40°C

−690

0xFD4E

1111 1101 0100 1110

DEVICE CONFIGURATION

The control registers listed in Table 14 provide a variety of user

configuration options. The SPI provides access to these registers,

one byte at a time, using the bit assignments shown in Figure 13.

Each register has 16 bits, where Bits[7:0] represent the lower

address and Bits[15:8] represent the upper address. Figure 15

provides an example of writing 0x03 to Address 0x22

(DEC_RATE[7:0]), using DIN = 0xA203. This example reduces

the sample rate by a factor of 8 (see Table 16).

DIN = 1010 0010 0000 0011 = 0xA203, WRITES 0x03 TO ADDRESS 0x22

SCLK

DIN

CS

Figure 15. SPI Sequence for Setting the Decimate Rate to 8 (DIN = 0xA203)

Dual Memory Structure

Writing configuration data to a control register updates its SRAM

contents, which are volatile. After optimizing each relevant control

register setting in a system, set GLOB_CMD[3] = 1 (DIN =

0xA808) to back these settings up in nonvolatile flash memory.

The flash backup process requires a valid power supply level for

the entire 72 ms process time. Table 14 provides a user register

memory map that includes a column of flash backup information.

A yes in this column indicates that a register has a mirror location

in flash and, when backed up properly, automatically restores itself

during startup or after a reset. Figure 16 provides a diagram of the

dual-memory structure used to manage operation and store critical

user settings.

NONVOLATILE

FLASH MEMORY

(NO SPI ACCESS)

MANUAL

FLASH

BACKUP

START-UP

RESET

VOLATILE

SRAM

SPI ACCESS

Figure 16. SRAM and Flash Memory Diagram