ADIS16305

Rev. 0 | Page 11 of 20

BURST READ DATA COLLECTION

Burst read data collection is a process-efficient method for collecting

data from the ADIS16305. In burst read, all output registers are

clocked out on DOUT, 16 bits at a time, in sequential data cycles

(each separated by one SCLK period). To start a burst read sequence,

set DIN = 0x3E00. The contents of each output register are then

shifted out on DOUT, starting with SUPPLY_OUT and ending with

AUX_ADC (see Figure 13). The addressing sequence shown in

Table 8 determines the order of the outputs in burst read.

OUTPUT DATA REGISTERS

Each output data register uses the format in Figure 12 and Table 9.

Figure 6 shows the positive direction for each inertial sensor. The

ND bit is equal to 1 when the register contains unread data. The

EA bit is high when any error/alarm flag in the DIAG_STAT

register is equal to 1.

MSB FOR 14-BIT OUTPUT

MSB FOR 12-BIT OUTPUT

ND EA

Figure 12. Output Register Bit Assignments

Table 9. Output Data Register Formats

Name

Address

Scale

Reference

SUPPLY_OUT

0x02

Power supply

Table 13

GYRO_OUT1

0x04

Gyroscope

Table 10

XACCL_OUT

0x0A

Acceleration (x)

Table 11

YACCL_OUT

0x0C

Acceleration (y)

Table 11

ZACCL_OUT

0x0E

Acceleration (z)

Table 11

TEMP_OUT2

0x10

Temperature

Table 14

PITCH_OUT

0x12

Pitch angle

Table 12

ROLL_OUT

0x14

Roll angle

Table 12

AUX_ADC

0x16

ADC measurement

Table 15

Note that the codes in Table 10, Table 11, Table 12, Table 13,

Table 14, and Table 15 assume typical sensitivity values.

Gyroscopes

The gyroscope output register, GYRO_OUT, uses a 14-bit, twos

complement digital format. When using the factory-default range

of ±300°/sec, each LSB translates into 0.05°/sec. Table 10 offers

some examples for translating the digital data into rotation rate

measurements. When the dynamic rage is set to ±150°/sec,

divide the rotation rate numbers in Table 10 by a factor of two.

When the dynamic rage is set to ±75°/sec, divide the rotation

rate numbers in Table 10 by a factor of four.

Table 10. Rotation Rate, Twos Complement Format

Rotation Rate

Decimal

Hex

Binary

+300°/sec

+6000 LSB

0x1770

XX01 0111 0111 0000

+0.1°/sec

+2 LSB

0x0002

XX00 0000 0000 0010

+0.05°/sec

+1 LSB

0x0001

XX00 0000 0000 0001

0°/sec

0 LSB

0x0000

XX00 0000 0000 0000

−0.05°/sec

−1 LSB

0x3FFF

XX11 1111 1111 1111

−0.1°/sec

−2 LSB

0x3FFE

XX11 1111 1111 1110

−300°/sec

−6000 LSB

0x2890

XX10 1000 1001 0000

Accelerometers

The accelerometer output registers, XACCL_OUT, YACCL_OUT,

and ZACCL_OUT, use a 14-bit, twos complement digital format.

Table 11 offers some examples for translating the digital data

into linear acceleration measurements

Table 11. Acceleration, Twos Complement Format

Acceleration

Decimal

Hex

Binary

+3.3 g

+5500 LSB

0x157C

XX01 0101 0111 1100

+1.2 mg

+2 LSB

0x0002

XX00 0000 0000 0010

+0.6 mg

+1 LSB

0x0001

XX00 0000 0000 0001

0 g

0 LSB

0x0000

XX00 0000 0000 0000

−0.6 mg

−1 LSB

0x3FFF

XX11 1111 1111 1111

−1.2 mg

−2 LSB

0x3FFE

XX11 1111 1111 1110

−3.3 g

−5500 LSB

0x2A84

XX10 1010 1000 0100

0x3E00

PREVIOUS

DON’T CARE

SUPPLY_OUT

GYRO_OUT

ROLL_OUT

AUX_ADC

123

910

XACCL_OUT

YACCL_OUT

45

CS

SCLK

DIN

DOUT

Figure 13. Burst Read Sequence