Address byte, Table 2, At83c24 – Rainbow Electronics AT83C24NDS User Manual
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4234F–SCR–10/05
AT83C24
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, A0/3V pins on reset) corresponds to the address given in the
address byte (A2, A1, A0 bits).
If the level is not stable on A2/CK pin (or A1/RST pin, or A0/3V pin) at reset, the user has to send
the commands to the possible address taken by the device.
If A2/CK to A0/3V are tied to the host microcontroller and their reset values are unknown, a gen-
eral call on the TWI bus allows to reset all the AT83C24 devices and set their address after
A2/CK to A0/3V are fixed.
Figure 2. Address Byte
Up to 8 devices can be connected on the same TWI bus. Each device is configured with a differ-
ent combination on A2/CK, A1/RST, A0/3V pins. The corresponding address byte values for
read/write operations are listed below.
Table 2. Address Byte Values
A2
(A2/CK pin)
A1
(A1/RST pin)
A0
(A0/3V pin)
Address Byte
for
Read
Command
Address Byte
for
Write
Command
0
0
0
0x41
0x40
0
0
1
0x43
0x42
0
1
0
0x45
0x44
0
1
1
0x47
0x46
1
0
0
0x49
0x48
1
0
1
0x4B
0x4A
1
1
0
0x4D
0x4C
1
1
1
0x4F
0x4E
b7
b6
b5
b4
b3
b2
b1
b0
0
0
1
0
A2
A1
A0
R/W
Slave Address on 7 Bits
1 for READ Command
0 for WRITE Command