PixArt Imaging Inc.
ADBS-A350 Optical Finger Navigation
ADBS-A350 Driven Packets
By request of the host, the ADBS-A350 acknowledges a read request and then outputs a data byte transmitting the most
significant bit (7) first. If the host intends to continue the data transfer, the host acknowledges the ADBS-A350. If the host
intends to terminate the transfer, it responds with not acknowledge (SDA = 1), and then drives SDA to generate a STOP
condition. The host can also drive a START condition if it wants to begin a new data transfer with the same ADBS-A350.
STOP or
START
Condition
ACK
7
6 – 1
0
ACK
7
6 – 1
0
NAK
NAK
SCL driven
by host
D6–D1
D0
ACK
D7
D7
D6–D1
D0
SDA
ADBS Driven
Packet
Host
Driven
ADBS Driven
Packet
Host
Driven
If the host responds with
an acknowledge (ACK),
the ADBS sends another
data byte
The host terminates data
transmission by responding
with a not acknowledge
(NAK), followed by a STOP
condition or another START
condition
Figure 21. Sensor packets
Example: Writing Data to Sensor Registers
The host writes a value of 0x02 to address 0x07 in the following illustration.
The example ADBS-A350 address is 0x57.
ADBS
Address
0 x 57
Register
Address
0 x 07
Data
0 x 02
Packet
Number
1
2
3
Packet
type
DA
RA
DP
7
0
0
7
0
7
0
SDA
host
START 1010111
0
0000111
ai
00000010
STOP
R/W
SDA
ADBS
ACK
ACK
ACK
Figure 22. TWI write
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PixArt Imaging Inc.
E-mail: fae_service@pixart.com.tw
22
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