BMA020 Bosch Sensortec, BMA020 Datasheet - Page 34

• Manufacturer Part Number: BMA020
• Description: 3-AXIS ACCELEROMETER DIGITAL I/F
• Manufacturer: Bosch Sensortec

Specifications of BMA020

• Axis: X, Y, Z
• Acceleration Range: ± 2g, 4g, 8g
• Sensitivity: 256LSB/g, 128LSB/g, 64LSB/g
• Voltage - Supply: 2 V ~ 3.6 V
• Output Type: Digital
• Bandwidth: 3kHz
• Interface: I²C, SPI
• Mounting Type: Surface Mount
• Package / Case: 12-LGA
• For Use With: 828-1014 - BMA020 TRIBOX DEMO BOARD W/USB828-1008 - BMA020 DAUGHTERCARD FOR DEV KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 828-1000-2

4.2.1 I²C protocol:
The BMA020 I²C slave address is coded on 7 bits (0111000b=38h) fixed by a metal option.
Thus I²C write address is 01110000b (=70h), read address is 01110001b (=71h).
After a start condition, the slave address + RW bit must be send. If the slave address does not
match with BMA020 there is no acknowledgement and the following data transfer will not affect
the chip. If the slave address corresponds to BMA020 it will acknowledge (pull SDA down
during 9th clock pulse) and data transfer is enabled. The 8th bit RW sets the chip in read or
write mode, RW=1 for reading, RW=0 for writing.
After slave address and RW bit, the master sends 1 control byte: the 7-bit register address and
one dummy bit.
When BMA020 is accessed in write mode, sequences of 2 bytes (= 1 control byte to define
which address will be written and 1 data byte) must be sent:
Figure 15: I²C multiple write protocol
Rev. 1.2
© 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.
Start
S
0
1
Slave Adress
1
1
0
0
0
RW ACK
0
Digital, triaxial acceleration sensor
…
X
X
0
0
0
0
Data sheet
BMA020
Register adress (0Fh)
Register adress (09h)
Page 34
Control byte
Control byte
0
0
1
1
0
1
0
1
1
1
ACK
ACK
X
X
X
X
Register data - adress 09h
Register data - adress 0Fh
X
X
Data byte
Data byte
X
X
Bosch Sensortec
X
X
X
X
30 May 2008
X
X
X
X
ACK
ACK Stop
…
P