ADIS16240/PCBZ Analog Devices Inc, ADIS16240/PCBZ Datasheet - Page 13

• Manufacturer Part Number: ADIS16240/PCBZ
• Description: BOARD EVAL FOR ADIS16240
• Manufacturer: Analog Devices Inc
• Series: iMEMS®, iSensor™r

Specifications of ADIS16240/PCBZ

• Sensor Type: Accelerometer, 3 Axis
• Sensing Range: ±19g
• Interface: SPI Serial
• Sensitivity: 51.4mg/LSB
• Voltage - Supply: 2.4 V ~ 3.6 V
• Embedded: No
• Utilized Ic / Part: ADIS16240
• Silicon Manufacturer: Analog Devices
• Application Sub Type: Shock Sensor
• Kit Application Type: Sensing - Motion / Vibration / Shock
• Silicon Core Number: ADIS16240
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption

For example, if CAPT_CTRL[2:0] = 100, then T = 4, which
organizes the buffer memory into 128 events of 64 samples each.
Event Organization
Each event contains a header, pretrigger data, and posttrigger data,
as shown in Figure 21. The event header provides information
about the conditions that occur when the capture takes place.
CAPT_CTRL[7:4] sets the number of pretrigger samples in
each event. If N
the first sample after the trigger follows the header.
Reading Event Data
The CAPT_BUF1, CAPT_BUF2, and CAPT_PNTR registers
manage user access to data in the capture buffer (see Table 18,
Table 19, and Table 20). The address pointer, CAPT_PNTR,
determines which capture memory location loads into the capture
buffer registers. It increments automatically with every CAPT_
BUF2 read. The most efficient method for reading the entire
buffer memory space is to alternate between the CAPT_BUF1
(DIN = 0x9600) and CAPT_BUF2 (DIN = 0x9800) read com-
mands. When alternating the read sequences in this manner,
the CAP_PNTR increments automatically and optimizes SPI
processing resources. Writing to the CAPT_PNTR register pro-
vides access to individual locations in the capture. For example,
writing 0x0138 (DIN = 0xC038, DIN = 0xC101) to the CAPT_
PNTR register causes the 311
to load into the CAP_BUF1 and CAPT_BUF2 locations (see
Figure 22).
POSTTRIGGER
PRETRIGGER
N
PRE
DATA
DATA
=
SAMPLES
N
16
Figure 20. Event Storage in Buffer Memory
8192
L
PRE
Figure 21. Default Event Organization
−
is negative, there is no pretrigger data and
6
BUFFER 2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
EVENT N
EVENT 1
EVENT 2
Z
Z
Z
Z
Z
Z
–26
–25
223
–1
0
1
th
sample in each buffer memory
E
XYZPEAK_OUT
Y
Y
Y
SUPPLY_OUT
Y
Y
Y
BUFFER 1
–26
–25
223
TEMP_OUT
–1
N
AUX_ADC
0
1
L
DATE
TIME
N
N
L
E
=
= 8 × 2
X
X
X
X
1024
X
X
–26
–25
223
–1
2
0
1
T
T
0
1
2
3
4
5
6
7
31
32
33
255
EVENT
HEADER
Rev. 0 | Page 13 of 16
Table 18. CAPT_BUF1 Register Bit Descriptions
Bit
[15:8]
[7:0]
1
Table 19. CAPT_BUF2 Register Bit Descriptions
Bit
[15:8]
[7:0]
1
Table 20. CAPT_PNTR Register Bit Descriptions
Bit
[15:13]
[7:0]
1
The EVNT_CNTR register (see Table 21) provides a running count
for the number of triggers (internal and external) that occur after
a buffer clear and/or reset. If this number is greater than the
number of events, this indicates that the device has experienced
trigger events that it could not capture because its capture buffer
is full. The EVNT_CNTR returns to 0x0000 after a buffer clear
(GLOB_CMD[6] = 1 by DIN = 0xCA40), or a factory reset
(GLOB_CMD[1] = 1 by DIN = 0xCA02). After a power cycle or
software reset command, the EVNT_CNTR contains the number
of events stored in the buffer memory.
Table 21. EVNT_CNTR Register Bit Descriptions
Bit
[15:0]
1
The EVNT_CNTR register is located at Address 0x1D[15:8] and Address 0x1C[7:0].
The CAPT_BUF1 register is located at Address 0x17[15:8] and Address 0x16[7:0].
The CAPT_BUF2 register is located at Address 0x19[15:8] and Address 0x18[7:0].
The CAPT_PNTR register is located at Address 0x41[15:8] and Address 0x40[7:0].
BUFFER 2
Description
Y-axis acceleration
X-axis acceleration
Description
Unused
Z-axis acceleration
Description
Unused
Buffer address that loads into CAPT_BUF1, CAPT_BUF2
Description
Binary event counter
CAPT_BUF2
Figure 22. Capture Buffer Data Flow Diagram
CAPT_PNTR
USER ACCESIBLE
INTERNAL MEMORY STRUCTURE
CAPT_BUF1
BUFFER 1
Format
Twos complement,
205.7 mg/LSB
Format
Twos complement,
205.7 mg/LSB
ADIS16240
1
1
1
1