Rainbow-electronics AT83C24NDS Instrukcja Użytkownika Pobierz pdf (Strona 7)

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/CK pin)

(A1/RST pin)

(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

b3 b2 b1

R/W

Slave Address on 7 Bits

1 for READ Command

0 for WRITE Command

1 2 3 4 5 6 7 8 9 10 11 12 ... 41 42

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Rainbow-electronics AT83C24NDS Instrukcja Użytkownika Strona 7