DRV201 Datasheet, PDF (8/17 Pages) Texas Instruments – VOICE COIL MOTOR DRIVER FOR CAMERA AUTO FOCUS

DRV201
SLVSB25 – AUGUST 2011
www.ti.com
Data transmission is initiated with a start bit from the controller as shown in Figure 3. The start condition is
recognized when the SDA line transitions from high to low during the high portion of the SCL signal. Upon
reception of a start bit, the device will receive serial data on the SDA input and check for valid address and
control information. If the appropriate slave address bits are set for the device, then the device will issue an
acknowledge pulse and prepare to receive the register address. Depending on the R/nW bit, the next byte
received from the master is written to the addressed register (R/nW = 0) or the device responds with 8-bit data
from the register (R/nW = 1). Data transmission is completed by either the reception of a stop condition or the
reception of the data word sent to the device. A stop condition is recognized as a low to high transition of the
SDA input during the high portion of the SCL signal. All other transitions of the SDA line must occur during the
low portion of the SCL signal. An acknowledge is issued after the reception of valid address, sub-address and
data words. The I²C interfaces will auto-sequence through register addresses, so that multiple data words can be
sent for a given I²C transmission. Reference Figure 4.
SDA
...
SCL
1
2
3
4
5
6
7
8
9
...
START CONDITION
ACKNOWLEDGE
Figure 3. I²C Start/Stop/Acknowledge Protocol
STOP CONDITION
t_LOW
t_r
t_f
t_H(STA)
SCL
t_H(STA)
SDA
t_(BUF)
P
S
t_H(DAT)
t_HIGH
t_S(DAT)
t_S(STA)
S
Figure 4. I²C Data Transmission Protocol
t_S(STO)
P
8
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