EVAL-ADXL346Z Analog Devices Inc, EVAL-ADXL346Z Datasheet - Page 14

no-image

EVAL-ADXL346Z

Manufacturer Part Number
EVAL-ADXL346Z
Description
Inertial Sensor Evaluation System
Manufacturer
Analog Devices Inc
Datasheets

Specifications of EVAL-ADXL346Z

Silicon Manufacturer
Analog Devices
Silicon Core Number
ADXL346
Kit Application Type
Sensing - Motion / Vibration / Shock
Application Sub Type
Accelerometer
Silicon Family Name
IMEMS
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
ADXL346
SERIAL COMMUNICATIONS
I
the ADXL346 operates as a slave. I
is tied high to V
V
default mode if the CS pin is left unconnected. Therefore, not
taking these precautions may result in an inability to communicate
with the part. In SPI mode, the CS pin is controlled by the bus
master. In both SPI and I
from the ADXL346 to the master device should be ignored during
writes to the ADXL346.
SPI
For SPI, either 3- or 4-wire configuration is possible, as shown in
the connection diagrams in Figure 34 and Figure 35. Clearing the
SPI bit (Bit D6) in the DATA_FORMAT register (Address 0x31)
selects 4-wire mode, whereas setting the SPI bit selects 3-wire
mode. The maximum SPI clock speed is 5 MHz with 100 pF
maximum loading, and the timing scheme follows clock polarity
(CPOL) = 1 and clock phase (CPHA) = 1. If power is applied to
the ADXL346 before the clock polarity and phase of the host
processor are configured, the CS pin should be brought high
before changing the clock polarity and phase. When using 3-wire
SPI, it is recommended that the SDO pin either be pulled up to
V
2
C and SPI digital communications are available. In both cases,
DD I/O
DD I/O
or be driven by an external controller because there is no
or be pulled down to GND via a 10 kΩ resistor.
Figure 34. 3-Wire SPI Connection Diagram
Figure 35. 4-Wire SPI Connection Diagram
DD I/O
ADXL346
ADXL346
. The CS pin should always be tied high to
SCLK
SCLK
SDIO
SDO
SDO
SDI
CS
CS
2
C modes of operation, data transmitted
2
C mode is enabled if the CS pin
PROCESSOR
PROCESSOR
D OUT
D IN/OUT
D OUT
D OUT
D OUT
D IN
D OUT
Rev. A | Page 14 of 40
CS is the serial port enable line and is controlled by the SPI master.
This line must go low at the start of a transmission and high at
the end of a transmission, as shown in
serial port clock and is supplied by the SPI master. SCLK should
idle high during a period of no transmission. SDI and SDO are
the serial data input and output, respectively. Data is updated
on the falling edge of SCLK and should be sampled on the
rising edge of SCLK.
To read or write multiple bytes in a single transmission, the
multiple-byte bit, located after the R/ W bit in the first byte transfer
(MB in
addressing and the first byte of data, each subsequent set of
clock pulses (eight clock pulses) causes the ADXL346 to point
to the next register for a read or write. This shifting continues
until the clock pulses cease and
or writes on different, nonsequential registers, CS must be
deasserted between transmissions and the new register must be
addressed separately.
The timing diagram for 3-wire SPI reads or writes is shown in
Figure 38. The 4-wire equivalents for SPI writes and reads are
shown in Figure 36 and Figure 37, respectively. For correct
operation of the part, the logic thresholds and timing parameters
in Table 9 and Table 10 must be met at all times.
Use of the 3200 Hz and 1600 Hz output data rates is recom-
mended only with SPI communication rates greater than or
equal to 2 MHz. The 800 Hz output data rate is recommended
only for communication speeds greater than or equal to 400 kHz,
and the remaining data rates scale proportionally. For example,
the minimum recommended communication speed for a 200 Hz
output data rate is 100 kHz. Operation at an output data rate
above the recommended maximum may result in undesirable
effects on the acceleration data, including missing samples or
additional noise.
Figure 36
to
Figure 38
), must be set. After the register
CS is deasserted. To perform reads
Figure 36
. SCLK is the

Related parts for EVAL-ADXL346Z