ADIS16300

Rev. 0 | Page 14 of 16

DIAGNOSTICS

Self-Test

Self-test offers the opportunity to verify the mechanical

integrity of each MEMS sensor. It applies an electrostatic force

to each sensor element, which results in mechanical displace-

ment that simulates a response to actual motion. Table 1 lists

the expected response for each sensor, which provides pass/fail

criteria. Set MSC_CTRL[10] = 1 (DIN = 0xB504) to run the

internal self-test routine, which exercises all inertial sensors,

measures each response, makes pass/fail decisions, and reports

them to error flags in the DIAG_STAT register. MSC_CTRL[10]

resets itself to 0 after completing the routine. MSC_CTRL[9:8]

(DIN = 0xB502 or 0xB501) provides manual control over the

self-test function. Table 20 gives an example test flow for using

this option.

Table 20. Manual Self-Test Example Sequence

DIN

Description

0xB601

SMPL_PRD[7:0] = 0x01, sample rate = 819.2 SPS.

0xB904

SENS_AVG[15:8] = 0x04, gyro range = ±300°/sec.

0xB802

SENS_AVG[7:0] = 0x02, 4-tap averaging filter.

Delay = 50 ms.

0x0400

Read GYRO_OUT.

0x0600

Read XACCL_OUT.

0x0800

Read YACCL_OUT.

0x0A00

Read ZACCL_OUT.

0xB502

MSC_CTRL[9] = 1, gyroscope negative self-test.

Delay = 50 ms.

0x0400

Read GYRO_OUT.

Determine whether the bias in the gyroscope

output changes according to the expectation set

in Table 2.

0xB501

MSC_CTRL[9:8] = 01, gyroscope/accelerometer

positive self-test.

Delay = 50 ms.

0x0400

Read GYRO_OUT.

0x0600

Read XACCL_OUT.

0x0800

Read YACCL_OUT.

0x0A00

Read ZACCL_OUT

Determine whether the bias in the gyroscope and

accelerometers changed according to the expect-

ation set in Table 2.

0xB500

MSC_CTRL[15:8] = 0x00.

Zero motion provides results that are more reliable. The settings

in Table 20 are flexible and provide opportunity for optimization

around speed and noise influence. For example, lowering the

filtering taps enables lower delay times but increases the oppor-

tunity for noise influence.

Memory Test

Setting MSC_CTRL[11] = 1 (DIN = 0xB508) does a check-sum

verification of the flash memory locations. The pass/fail criteria

load into the DIAG_STAT[6] register.

Status

The error flags provide indicator functions for common system

level issues. All of the flags clear (set to 0) after each DIAG_STAT

register read cycle. If an error condition remains, the error flag

returns to 1 during the next sample cycle. DIAG_STAT[1:0]

does not require a read of this register to return to zero. If the

power supply voltage goes back into range, these two flags clear

automatically.

Table 21. DIAG_STAT Bit Descriptions

Bit

Description

[15]

Z-axis accelerometer self-test failure

1 = error condition, 0 = normal operation

[14]

Y-axis accelerometer self-test failure

1 = error condition, 0 = normal operation

[13]

X-axis accelerometer self-test failure

1 = error condition, 0 = normal operation

[12:11]

Not used

[10]

Gyroscope self-test failure

1 = error condition, 0 = normal operation

[9]

Alarm 2 status

1 = active, 0 = inactive

[8]

Alarm 1 status

1 = active, 0 = inactive

[7]

Not used

[6]

Flash test, check-sum flag

1 = failure, 0 = normal operation

[5]

Self-test diagnostic error flag

1 = error condition, 0 = normal operation

[4]

Sensor overrange

1 = error condition, 0 = normal operation

[3]

SPI communications failure

1 = error condition, 0 = normal operation

[2]

Flash update failed

1 = error condition, 0 = normal operation

[1]

Power supply above 5.25 V

1 = power supply ≥ 5.25 V, 0 = power supply ≤ 5.25 V

[0]

Power supply below 4.75 V

1 = power supply ≤ 4.75 V, 0 = power supply ≥ 4.75 V

Alarm Registers

The alarm function provides monitoring for two independent

conditions. The ALM_CTRL register provides control inputs

for data source, data filtering (prior to comparison), static

comparison, dynamic rate-of-change comparison, and output

indicator configurations. The ALM_MAGx registers establish the

trigger threshold and polarity configurations.

Table 25 gives an example of how to configure a static alarm.

The ALM_SMPLx registers provide the numbers of samples to

use in the dynamic rate-of-change configuration. The period

equals the number in the ALM_SMPLx register, multiplied by

the sample period time, established by the SMPL_PRD register.

See Table 26 for an example of how to configure the sensor for

this type of function.