3-AXIS ACCELEROMETER DIGITAL I/F

BMA250

Manufacturer Part NumberBMA250
Description3-AXIS ACCELEROMETER DIGITAL I/F
ManufacturerBosch Sensortec
Series-
BMA250 datasheets
 


Specifications of BMA250

Featured ProductBMA250 - Digital, Triaxial Acceleration SensorAxisX, Y, Z
Acceleration Range±2g, 4g, 8g, 16gSensitivity256LSB/g, 128LSB/g, 64LSB/g, 16LSB/g
Voltage - Supply1.62 V ~ 3.6 VOutput TypeI²C™, SPI™
Bandwidth8Hz ~ 1kHzInterfaceI²C, SPI
Mounting TypeSurface MountPackage / Case12-VQFN
Lead Free Status / Rohs StatusLead free / RoHS CompliantFor Use With828-1024 - BMA250 DAUGHTERCARD FOR DEV KIT
Other names828-1023-2  
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Page 57/74

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The data bits are used as follows:
Bit0: Read/Write bit. When 0, the data SDI is written into the chip. When 1, the data SDO from
the chip is read.
Bit1-7: Address AD(6:0).
Bit8-15: when in write mode, these are the data SDI, which will be written into the address.
When in read mode, these are the data SDO, which are read from the address.
Multiple read operations are possible by keeping CSB low and continuing the data transfer. Only
the first register address has to be written. Addresses are automatically incremented after each
read access as long as CSB stays active low.
The principle of multiple read is shown in figure 13:
Control byte
Register adress (02h)
RW
Start
CSB
=
1
0
0
0
0
0
1
0
X
0
In SPI 3-wire configuration CSB (chip select low active), SCK (serial clock), and SDI (serial
data input and output) pins are used. The communication starts when the CSB is pulled low by
the SPI master and stops when CSB is pulled high. SCK is also controlled by SPI master. SDI is
driven (when used as input of the device) at the falling edge of SCK and should be captured
(when used as the output of the device) at the rising edge of SCK.
The protocol as such is the same in 3-wire configuration as it is in 4-wire configuration. The
basic operation waveform (read or write access) for 3-wire configuration is depicted in figure 14:
CSB
SCK
SDI
RW
AD6
AD5
Figure 14: 3-wire basic SPI read or write sequence (mode ´11´)
Rev. 1.0
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
BMA250
Data sheet
Data byte
Data byte
Data register - adress 02h
Data register - adress 03h
X
X
X
X
X
X
X
X
X
X
X
Figure 13: SPI multiple read
AD4
AD3
AD2
AD1
AD0
DI7
DI6
DI5
Page 57 / not for publishing
Bosch Sensortec
Data byte
Data register - adress 04h
X
X
X
X
X
X
X
X
X
X
X
DI4
DI3
DI2
DI1
DI0
03 March 2011
Stop
CSB
=
X
1