Figure 20-5: 10 - Bit Address Format
1
1
1
1
0
Reserved for 10-Bit Address
S
A6
A7
A5
A4
A3
A2
A1
A0
S: Start Condition
R/W: Read/Write Pulse
ACK: Acknowledge (Sent by Slave)
ACK
ACK
R/W
A8
A9
The following table defines the special purpose and reserved first byte addresses. †
Table 20-1: I2C Definition of Bits in First Byte †
Description
R/W Bit
Slave Address
General call address. The I2C
controller places the data in the
receive buffer and issues a general
call interrupt.
0
0000 000
START byte. For more details,
refer to “START BYTE Transfer
Protocol”
1
0000 000
CBUS address. The I2C controller
ignores these accesses.
X
0000 001
Reserved
X
0000 010
Reserved
X
0000 011
Unused
X
0000 1XX
Reserved
X
1111 1XX
10-bit slave addressing.
X
1111 0XX
Note to Table:
1. ‘X’ indicates do not care.
Related Information
on page 20-8
Transmitting and Receiving Protocol
The master can initiate data transmission and reception to or from the bus, acting as either a master-
transmitter or master-receiver. A slave responds to requests from the master to either transmit data or receive
data to or from the bus, acting as either a slave-transmitter or slave-receiver, respectively. †
Master-Transmitter and Slave-Receiver
All data is transmitted in byte format, with no limit on the number of bytes transferred per data transfer.
After the master sends the address and R/W bit or the master transmits a byte of data to the slave, the slave-
I2C Controller
Altera Corporation
cv_54020
Transmitting and Receiving Protocol
20-6
2013.12.30