Rainbow Electronics AT83C26 - Manual (Page 11)

11
7511B–SCR–10/05
AT83C26
Figure 1. Data transfer on TWI bus
Address Byte The first byte to send to the device is the address byte. The device controls if the hardware
address (A2/CK, A1/RST pins on reset) corresponds to the address given in the address byte
(A2, A1 bits).
If the level is not stable on A2/CK pin at reset, the user has to manage the possible address
taken by the device.
Figure 2. Address Byte
Up to 4 devices can be connected on the same TWI bus. Each device is configured with a differ-
ent combination on A2/CK, A1/RST pins. The address byte of each device for read/write
operations are listed below.
SDA
SCL
start condition stop condition
1 2 3 4 5 6 7 8 9
acknowledgement
from slave
Address byte
command
and/or data
Table 2. Address Byte Values
A2
(A2/CK pin)
A1
(A1/RST pin)
Address Byte
for
Read
Command
Address Byte
for
Write
Command
0 0 0x43 0x42
0 1 0x47 0x46
1 0 0x4B 0x4A
1 1 0x4F 0x4E
b7 b6 b5 b4 b3 b2 b1 b0
0 0 1 0 A2 A1 1 R/W
Slave Address on 7 Bits
1 for READ Command
0 for WRITE Command