Harman Kardon AVR 155 Service Manual ▷ View online
M24C64, M24C32
4/26
SUMMARY DESCRIPTION
These I
2
C-compatible electrically erasable pro-
grammable memory (EEPROM) devices are orga-
nized as 8192 x 8 bits (M24C64) and 4096 x 8 bits
(M24C32).
nized as 8192 x 8 bits (M24C64) and 4096 x 8 bits
(M24C32).
Figure 2. Logic Diagram
I
2
C uses a two-wire serial interface, comprising a
bi-directional data line and a clock line. The devic-
es carry a built-in 4-bit Device Type Identifier code
(1010) in accordance with the I
es carry a built-in 4-bit Device Type Identifier code
(1010) in accordance with the I
2
C bus definition.
The device behaves as a slave in the I
2
C protocol,
with all memory operations synchronized by the
serial clock. Read and Write operations are initiat-
ed by a Start condition, generated by the bus mas-
ter. The Start condition is followed by a Device
Select Code and Read/Write bit (RW) (as de-
scribed in
serial clock. Read and Write operations are initiat-
ed by a Start condition, generated by the bus mas-
ter. The Start condition is followed by a Device
Select Code and Read/Write bit (RW) (as de-
scribed in
Table 3.
), terminated by an acknowl-
edge bit.
When writing data to the memory, the device in-
serts an acknowledge bit during the 9
When writing data to the memory, the device in-
serts an acknowledge bit during the 9
th
bit time,
following the bus master’s 8-bit transmission.
When data is read by the bus master, the bus
master acknowledges the receipt of the data byte
in the same way. Data transfers are terminated by
a Stop condition after an Ack for Write, and after a
NoAck for Read.
When data is read by the bus master, the bus
master acknowledges the receipt of the data byte
in the same way. Data transfers are terminated by
a Stop condition after an Ack for Write, and after a
NoAck for Read.
Table 2. Signal Names
Power On Reset: V
CC
Lock-Out Write Protect
In order to prevent data corruption and inadvertent
Write operations during Power-up, a Power On
Reset (POR) circuit is included. At Power-up, the
internal reset is held active until V
Write operations during Power-up, a Power On
Reset (POR) circuit is included. At Power-up, the
internal reset is held active until V
CC
has reached
the Power On Reset (POR) threshold voltage, and
all operations are disabled – the device will not re-
spond to any command. In the same way, when
V
all operations are disabled – the device will not re-
spond to any command. In the same way, when
V
CC
drops from the operating voltage, below the
Power On Reset (POR) threshold voltage, all op-
erations are disabled and the device will not re-
spond to any command.
A stable and valid V
erations are disabled and the device will not re-
spond to any command.
A stable and valid V
CC
(as defined in
Table 9.
and
Table 10.
) must be applied before applying any
logic signal.
Figure 3. DIP, SO, TSSOP and UFDFPN
Connections
Connections
Note: See
PACKAGE MECHANICAL
section for package dimen-
sions, and how to identify pin-1.
AI01844B
3
E0-E2
SDA
VCC
M24C64
M24C32
M24C32
WC
SCL
VSS
E0, E1, E2
Chip Enable
SDA
Serial Data
SCL
Serial Clock
WC
Write Control
V
CC
Supply Voltage
V
SS
Ground
SDA
VSS
SCL
WC
E1
E0
VCC
E2
AI01845C
M24C64
M24C32
M24C32
1
2
3
4
8
7
6
5
harman/kardon
AVR 155/230 Service Manual
Page 57 of 92
M24C64, M24C32
8/26
DEVICE OPERATION
The device supports the I
2
C protocol. This is sum-
marized in
Figure 5.
. Any device that sends data
on to the bus is defined to be a transmitter, and
any device that reads the data to be a receiver.
The device that controls the data transfer is known
as the bus master, and the other as the slave de-
vice. A data transfer can only be initiated by the
bus master, which will also provide the serial clock
for synchronization. The M24Cxx device is always
a slave in all communication.
Start Condition
Start is identified by a falling edge of Serial Data
(SDA) while Serial Clock (SCL) is stable in the
High state. A Start condition must precede any
data transfer command. The device continuously
monitors (except during a Write cycle) Serial Data
(SDA) and Serial Clock (SCL) for a Start condition,
and will not respond unless one is given.
Stop Condition
Stop is identified by a rising edge of Serial Data
(SDA) while Serial Clock (SCL) is stable and driv-
en High. A Stop condition terminates communica-
tion between the device and the bus master. A
Read command that is followed by NoAck can be
followed by a Stop condition to force the device
into the Stand-by mode. A Stop condition at the
end of a Write command triggers the internal Write
cycle.
Acknowledge Bit (ACK)
The acknowledge bit is used to indicate a success-
ful byte transfer. The bus transmitter, whether it be
bus master or slave device, releases Serial Data
(SDA) after sending eight bits of data. During the
9
any device that reads the data to be a receiver.
The device that controls the data transfer is known
as the bus master, and the other as the slave de-
vice. A data transfer can only be initiated by the
bus master, which will also provide the serial clock
for synchronization. The M24Cxx device is always
a slave in all communication.
Start Condition
Start is identified by a falling edge of Serial Data
(SDA) while Serial Clock (SCL) is stable in the
High state. A Start condition must precede any
data transfer command. The device continuously
monitors (except during a Write cycle) Serial Data
(SDA) and Serial Clock (SCL) for a Start condition,
and will not respond unless one is given.
Stop Condition
Stop is identified by a rising edge of Serial Data
(SDA) while Serial Clock (SCL) is stable and driv-
en High. A Stop condition terminates communica-
tion between the device and the bus master. A
Read command that is followed by NoAck can be
followed by a Stop condition to force the device
into the Stand-by mode. A Stop condition at the
end of a Write command triggers the internal Write
cycle.
Acknowledge Bit (ACK)
The acknowledge bit is used to indicate a success-
ful byte transfer. The bus transmitter, whether it be
bus master or slave device, releases Serial Data
(SDA) after sending eight bits of data. During the
9
th
clock pulse period, the receiver pulls Serial
Data (SDA) Low to acknowledge the receipt of the
eight data bits.
Data Input
During data input, the device samples Serial Data
(SDA) on the rising edge of Serial Clock (SCL).
For correct device operation, Serial Data (SDA)
must be stable during the rising edge of Serial
Clock (SCL), and the Serial Data (SDA) signal
must change
eight data bits.
Data Input
During data input, the device samples Serial Data
(SDA) on the rising edge of Serial Clock (SCL).
For correct device operation, Serial Data (SDA)
must be stable during the rising edge of Serial
Clock (SCL), and the Serial Data (SDA) signal
must change
only
when Serial Clock (SCL) is driv-
en Low.
Memory Addressing
To start communication between the bus master
and the slave device, the bus master must initiate
a Start condition. Following this, the bus master
sends the Device Select Code, shown in
Memory Addressing
To start communication between the bus master
and the slave device, the bus master must initiate
a Start condition. Following this, the bus master
sends the Device Select Code, shown in
Table 3.
(on Serial Data (SDA), most significant bit first).
The Device Select Code consists of a 4-bit Device
Type Identifier, and a 3-bit Chip Enable “Address”
(E2, E1, E0). To address the memory array, the 4-
bit Device Type Identifier is 1010b.
Up to eight memory devices can be connected on
a single I
The Device Select Code consists of a 4-bit Device
Type Identifier, and a 3-bit Chip Enable “Address”
(E2, E1, E0). To address the memory array, the 4-
bit Device Type Identifier is 1010b.
Up to eight memory devices can be connected on
a single I
2
C bus. Each one is given a unique 3-bit
code on the Chip Enable (E0, E1, E2) inputs.
When the Device Select Code is received, the de-
vice only responds if the Chip Enable Address is
the same as the value on the Chip Enable (E0, E1,
E2) inputs.
The 8
When the Device Select Code is received, the de-
vice only responds if the Chip Enable Address is
the same as the value on the Chip Enable (E0, E1,
E2) inputs.
The 8
th
bit is the Read/Write bit (RW). This bit is
set to 1 for Read and 0 for Write operations.
If a match occurs on the Device Select code, the
corresponding device gives an acknowledgment
on Serial Data (SDA) during the 9
If a match occurs on the Device Select code, the
corresponding device gives an acknowledgment
on Serial Data (SDA) during the 9
th
bit time. If the
device does not match the Device Select code, it
deselects itself from the bus, and goes into Stand-
by mode.
deselects itself from the bus, and goes into Stand-
by mode.
Table 6. Operating Modes
Note: 1. X =
V
IH
or V
IL
.
Mode
RW bit
WC
1
Bytes
Initial Sequence
Current Address Read
1
X
1
START, Device Select, RW = 1
Random Address Read
0
X
1
START, Device Select, RW = 0, Address
1
X
reSTART, Device Select, RW = 1
Sequential Read
1
X
≥
1
Similar to Current or Random Address Read
Byte Write
0
V
IL
1
START, Device Select, RW = 0
Page Write
0
V
IL
≤
32
START, Device Select, RW = 0
harman/kardon
AVR 155/230 Service Manual
Page 58 of 92
MITSUMI
Video Switch · 75
Ω
driver · Y/C mix MM1501
Measuring Circuit
MM1501
MM1502
MM1503
MM1504
harman/kardon
AVR 155/230 Service Manual
Page 59 of 92
MITSUMI
Video Switch · 75
Ω
driver · Y/C mix MM1501
MM1505
MM1506
MM1507
MM1508
harman/kardon
AVR 155/230 Service Manual
Page 60 of 92
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