ADIS16136/PCBZ AD [Analog Devices], ADIS16136/PCBZ Datasheet - Page 14

• Manufacturer Part Number: ADIS16136/PCBZ
• Manufacturer: AD [Analog Devices]

ALARMS
The alarm function provides monitoring for two independent
conditions. Table 22 contains a list of registers that provide
configuration and control inputs for the alarm function.
Table 22. Registers for Alarm Configuration
Register
ALM_MAG1
ALM_MAG2
ALM_SMPL1
ALM_SMPL2
ALM_CTRL
The ALM_CTRL register (see Table 26) provides data source
selection (Bits[15:8]), static/dynamic setting for each alarm
(Bits[7:6]), trigger polarity (Bits[5:4]), data source filtering
(Bit 3), and an alarm indicator signal (Bits[2:0]).
STATIC ALARM USE
The static alarms setting compares the data source selection
(ALM_CTRL[15:8]) with the values in the ALM_MAGx
registers in Table 23 and Table 24. The data format in these
registers matches the format of the data selection in
ALM_CTRL[15:8]. ALM_CTRL[5:4] provide polarity
settings. See Table 27 for a static alarm configuration
example.
Table 23. ALM_MAG1 Bit Descriptions
Bits
[15:0]
Table 24. ALM_MAG2 Bit Descriptions
Bits
[15:0]
DYNAMIC ALARM USE
The dynamic alarm setting monitors the data selection for a
rate-of-change comparison. The rate of change is represented
by the magnitude in the ALM_MAGx registers over the time
represented by the number of samples in the ALM_SMPLx
register (see Table 25). See Table 27 for a dynamic alarm
configuration example.
Table 25. ALM_SMPL1, ALM_SMPL2 Bit Descriptions
Bits
[15:8]
[7:0]
ALARM REPORTING
DIAG_STAT[9:8] provide error flags that indicate an alarm
condition. ALM_CTRL[2:0] provide controls for a hardware
indicator using DIO1 or DIO2.
ADIS16136
Description (Default = 0x0000)
Threshold setting; matches format of the
ALM_CTRL[11:8] selection
Description (Default = 0x0000)
Threshold setting; matches for format of the
ALM_CTRL[15:12] selection
Description (Default = 0x0000)
Not used
Binary, number of samples (both 0x00 and 0x01 = 1)
Address
0x10
0x12
0x14
0x16
0x18
Description
Alarm 1, trigger setting
Alarm 2, trigger setting
Alarm 1, sample period
Alarm 2, sample period
Alarm configuration
Rev. A | Page 14 of 20
Table 26. ALM_CTRL Bit Descriptions
Bits
[15:12]
[11:8]
7
6
5
4
3
2
1
0
1
Alarm Example
Table 27 offers an example that configures Alarm 1 to trigger
when filtered GYRO_OUT data drops below 50°/sec and Alarm 2
to trigger when filtered GYRO_OUT data changes by more
than 50°/sec over a 100 ms period, or 500°/sec
setting helps reduce false triggers from noise and refine the
accuracy of the trigger points. The ALM_SMPL2 setting of
102 samples provides a comparison period that is 99.6 ms for
an internal sample rate of 1024 SPS. There is no need to pro-
gram ALM_SMPL1 because Alarm 1 is a static alarm in this
example.
Table 27. Alarm Configuration Example 1
DIN
0x9911,
0x98AF
0x930A,
0x92AF
0x910A,
0x90AF
0x9666
Filtering applies to GYRO_OUT only.
Description (Default = 0x0000)
Alarm 2 source selection
0000 = disable
0001 = GYRO_OUT (does not include GYRO_OUT2)
0010 = TEMP_OUT
0011 = DIAG_STAT
Alarm 1 source selection (same as Alarm 2)
Rate-of-change enable for Alarm 2
(1 = rate of change, 0 = static level)
Rate-of-change enable for Alarm 1
(1 = rate of change, 0 = static level)
Comparison polarity for Alarm 2
(1 specifies >ALM_MAG2, 0 specifies <ALM_MAG2)
Comparison polarity for Alarm 1
(1 specifies >ALM_MAG1, 0 specifies <ALM_MAG1)
Comparison data filter setting
(1 = Bartlett filter, 0 = no filtering)
Alarm output enable
(1 = enabled, 0 = disabled)
Alarm output polarity
(1 = active high, 0 = active low)
Alarm output line select
(1 = DIO2, 0 = DIO1)
Description
ALM_CTRL = 0x11AF
Alarm 2: dynamic; ΔGYRO_OUT
(Δtime, ALM_ SMPL2) > ALM_MAG2
Alarm 1: static; GYRO_OUT < ALM_MAG1
use filtered data source for comparison
DIO2 output indicator, positive polarity
ALM_MAG2 = 0x0AAF, (+50°/sec)
ALM_MAG1 = 0x0AAF, (+50°/sec)
ALM_SMPL2[7:0] = 0x66, (102 samples)
1
2
Data Sheet
. The filter