AT83C24 ATMEL Corporation, AT83C24 Datasheet - Page 7

• Manufacturer Part Number: AT83C24
• Description: Smart Card Reader Interface with Power Management
• Manufacturer: ATMEL Corporation

Address Byte
4234E–SCR–09/04
The first byte to send to the device is the address byte. The device controls if the hard-
ware 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 general call on the TWI bus allows to reset all the AT83C24 devices and set
their address after A2/CK to A0/3V are fixed.
Up to 8 devices can be connected on the same TWI bus. Each device is configured with
a different 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
Figure 2. Address Byte
(A2/CK pin)
A2
0
0
0
0
1
1
1
1
b7
0
(A1/RST pin)
Slave Address on 7 Bits
b6
1
A1
0
0
1
1
0
0
1
1
b5
0
b4
0
(A0/3V pin)
A2
b3
A0
0
1
0
1
0
1
0
1
b2
A1
1 for READ Command
0 for WRITE Command
b1
A0
Address Byte
R/W
b0
Command
Read
0x4D
0x4B
0x4F
0x41
0x43
0x45
0x47
0x49
for
AT83C24
Address Byte
Command
Write
0x4A
0x4C
0x4E
0x40
0x42
0x44
0x46
0x48
for
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