ADIS16501SLASHPCBZ datasheet(23/45 Pages) AD

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Data Sheet

ADIS16501

THEORY OF OPERATION

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Rev. B | 23 of 45

BURST READ FUNCTION

The burst read function provides a way to read a batch of output

data registers, using a continuous stream of bits, at a rate of up to

1 MHz (SCLK). This method does not require a stall time between

each 16-bit segment (see Figure 3). As shown in Figure 42, start

this mode by setting DIN = 0x6800, and then read each of the

registers in the sequence out of DOUT while keeping CS low for

the entire data transfer sequence. However, keeping the CS pin

low after a burst transfer is complete can delay the next data ready

pulse, and potentially interfere with the processing of the next IMU

sample.

The three options for burst mode include: scaled sync mode on

or off, BURST32 enabled and disabled, and BURST_SEL = 0 or

BURSET_SEL = 1. This results in eight possible burst data formats.

Scaled Sync Mode Enabled vs. Disabled

The only differences in the burst data format between these two

modes are the final two bytes in a burst. In scaled sync mode, the

final two bytes are the values of the TIME_STAMP registers. When

scaled sync mode is disabled, the final two bytes are the values

in the DATA_CNTR registers. As always, Bits[15:8] appear before

Bits[7:0] in both modes.

For the rest of the Burst Read Function section, it is assumed that

scaled sync mode is disabled.

16-Bit Burst Mode with BURST_SEL = 0

In 16-bit burst mode with BURST_SEL = 0, a burst contains cali-

brated gyroscope and accelerometer data in 16-bit format. This

mode is particularly appropriate for cases where there is no deci-

mation or filtering. In this mode, with this particular setting, the

sample rate is high (~2 kSPS) and the lower 16 bits are not

used except in cases where the user is running these actions of

averaging/filtering.

Figure 42. Burst Read Sequence with BURST_SEL = 0

The sequence of registers (and checksum value) in the burst

read includes the following registers and value: DIAG_STAT,

X_GYRO_OUT, Y_GYRO_OUT, Z_GYRO_OUT, X_ACCL_OUT,

Y_ACCL_OUT, Z_ACCL_OUT, TEMP_OUT, DATA_ CNTR, and the

checksum value.

In these cases, use the following formula to verify the 16-bit check-

sum value, treating each byte in the formula as an independent,

unsigned, 8-bit number:

Checksum = DIAG_STAT, Bits[15:8] + DIAG_STAT, Bits[7:0] +

X_GYRO_OUT, Bits[15:8] + X_GYRO_OUT, Bits[7:0] +

Y_GYRO_OUT, Bits[15:8] + Y_GYRO_OUT, Bits[7:0] +

Z_GYRO_OUT, Bits[15:8] + Z_GYRO_OUT, Bits[7:0] +

X_ACCL_OUT, Bits[15:8] + X_ACCL_OUT, Bits[7:0] +

Y_ACCL_OUT, Bits[15:8] + Y_ACCL_OUT, Bits[7:0] +

Z_ACCL_OUT, Bits[15:8] + Z_ACCL_OUT, Bits[7:0] +

TEMP_OUT, Bits[15:8] + TEMP_OUT, Bits[7:0] +

DATA_CNTR, Bits[15:8] + DATA_CNTR, Bits[7:0]

16-Bit Burst Mode with BURST_SEL = 1

In 16-bit burst mode with BURST_SEL = 1, a burst contains

calibrated delta angle and delta velocity data in 16-bit format.

This mode is particularly appropriate for cases where there is

no decimation or filtering. In this mode, with this particular setting,

the sample rate is high (~2 kSPS) and the lower 16 bits are not

used.

Figure 43. Burst Read Sequence with BURST_SEL = 1

The sequence of registers (and checksum value) in the burst read

includes the following registers and value: DIAG_STAT, X_DEL-

TANG_OUT, Y_DELTANG_OUT, Z_DELTANG_OUT, X_DELT-

VEL_OUT, Y_DELTVEL_OUT, Z_DELTVEL_OUT, TEMP_OUT, DA-

TA_ CNTR, and the checksum value.

In these cases, use the following formula to verify the 16-bit check-

sum value, treating each byte in the formula as an independent,

unsigned, 8-bit number:

Checksum = DIAG_STAT, Bits[15:8] + DIAG_STAT, Bits[7:0] +

X_DELTANG_OUT, Bits[15:8] + X_DELTANG_OUT, Bits[7:0] +

Y_DELTANG_OUT, Bits[15:8] + Y_DELTANG_OUT, Bits[7:0] +

Z_DELTANG_OUT, Bits[15:8] + Z_DELTANG_OUT, Bits[7:0] +

X_DELTVEL_OUT, Bits[15:8] + X_DELTVEL_OUT, Bits[7:0] +

Y_DELTVEL_OUT, Bits[15:8] + Y_DELTVEL_OUT, Bits[7:0] +

Z_DELTVEL_OUT, Bits[15:8] + Z_DELTVEL_OUT, Bits[7:0] +

TEMP_OUT, Bits[15:8] + TEMP_OUT, Bits[7:0] + DATA_CNTR,

Bits[15:8] + DATA_CNTR, Bits[7:0]

32-Bit Burst Mode with BURST_SEL = 0

In 32-bit burst mode with BURST_SEL = 0, a burst contains cali-

brated gyroscope and accelerometer data in 32-bit format. This

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