ST M24C64, M24C32 User Manual

M24C64

M24C32

64Kbit and 32Kbit Serial I²C Bus EEPROM

FEATURES SUMMARY

■Two-Wire I2C Serial Interface Supports 400kHz Protocol

■Single Supply Voltage:

–4.5 to 5.5V for M24Cxx

–2.5 to 5.5V for M24Cxx-W

–1.8 to 5.5V for M24Cxx-R

■Write Control Input

■BYTE and PAGE WRITE (up to 32 Bytes)

■RANDOM and SEQUENTIAL READ Modes

■Self-Timed Programming Cycle

■Automatic Address Incrementing

■Enhanced ESD/Latch-Up Protection

■More than 1 Million Erase/Write Cycles

■More than 40-Year Data Retention

Table 1. Product List

Reference

Part Number

M24C64

M24C64 M24C64-W

M24C64-R

M24C32

M24C32 M24C32-W

M24C32-R

Figure 1. Packages

PDIP8 (BN)

SO8 (MN) 150 mil width

TSSOP8 (DW) 169 mil width

UFDFPN8 (MB) 2x3mm² (MLP)

January 2005

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M24C64, M24C32

TABLE OF CONTENTS

FEATURES SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Table 1. Product List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Figure 1. Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

SUMMARY DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Figure 2. Logic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Table 2. Signal Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Power On Reset: VCC Lock-Out Write Protect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Figure 3. DIP, SO, TSSOP and UFDFPN Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

SIGNAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Serial Clock (SCL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Serial Data (SDA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Chip Enable (E0, E1, E2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Write Control (WC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Figure 4. Maximum RL Value versus Bus Capacitance (CBUS) for an I2C Bus . . . . . . . . . . . . . . . . 5 Figure 5. I2C Bus Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Table 3. Device Select Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Table 4. Most Significant Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Table 5. Least Significant Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

MEMORY ORGANIZATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Figure 6. Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

DEVICE OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Start Condition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Stop Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Acknowledge Bit (ACK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Data Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Memory Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Table 6. Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Figure 7. Write Mode Sequences with WC=1 (data write inhibited) . . . . . . . . . . . . . . . . . . . . . . . . . 9

Write Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Byte Write. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Page Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Figure 8. Write Mode Sequences with WC=0 (data write enabled) . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 9. Write Cycle Polling Flowchart using ACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Minimizing System Delays by Polling On ACK. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Figure 10.Read Mode Sequences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Read Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Random Address Read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Current Address Read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Sequential Read. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

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M24C64, M24C32

Acknowledge in Read Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

INITIAL DELIVERY STATE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

MAXIMUM RATING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Table 7. Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

DC AND AC PARAMETERS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Table 8. Operating Conditions (M24Cxx-6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Table 9. Operating Conditions (M24Cxx-W) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Table 10. Operating Conditions (M24Cxx-R). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Table 11. AC Measurement Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Figure 11.AC Measurement I/O Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Table 12. Input Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Table 13. DC Characteristics (M24Cxx(1), M24Cxx-W6 and M24Cxx-W3) . . . . . . . . . . . . . . . . . . . 16

Table 14. DC Characteristics (M24Cxx-W6 and M24Cxx-W3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Table 15. DC Characteristics (M24Cxx-R) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Table 16. AC Characteristics (M24Cxx-6, M24Cxx-W6 and M24Cxx-W3) . . . . . . . . . . . . . . . . . . . 18 Table 17. AC Characteristics (M24Cxx-R). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Figure 12.AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

PACKAGE MECHANICAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 13.PDIP8 – 8 pin Plastic DIP, 0.25mm lead frame, Package Outline . . . . . . . . . . . . . . . . . 20 Table 18. PDIP8 – 8 pin Plastic DIP, 0.25mm lead frame, Package Mechanical Data . . . . . . . . . . 20 Figure 14.SO8 narrow – 8 lead Plastic Small Outline, 150 mils body width, Package Outline . . . . 21 Table 19. SO8 narrow – 8 lead Plastic Small Outline, 150 mils body width,

Package Mechanical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Figure 15.TSSOP8 – 8 lead Thin Shrink Small Outline, Package Outline . . . . . . . . . . . . . . . . . . . 22 Table 20. TSSOP8 – 8 lead Thin Shrink Small Outline, Package Mechanical Data . . . . . . . . . . . . 22 Figure 16.UFDFPN8 (MLP8) – 8-lead Ultra thin Fine pitch Dual Flat Package No lead 2x3mm. . . 23 Table 21. UFDFPN8 (MLP8) – 8-lead Ultra thin Fine pitch Dual Flat Package No lead 2x3mm,

Package Mechanical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

PART NUMBERING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Table 22. Ordering Information Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

REVISION HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Table 23. Document Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

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M24C64, M24C32

SUMMARY DESCRIPTION

These I2C-compatible electrically erasable programmable memory (EEPROM) devices are organized as 8192 x 8 bits (M24C64) and 4096 x 8 bits (M24C32).

Figure 2. Logic Diagram

VCC

E0-E2

SDA

M24C64

SCL M24C32

VSS

AI01844B

I2C uses a two-wire serial interface, comprising a bi-directional data line and a clock line. The devices carry a built-in 4-bit Device Type Identifier code (1010) in accordance with the I2C bus definition.

The device behaves as a slave in the I2C protocol, with all memory operations synchronized by the serial clock. Read and Write operations are initiated by a Start condition, generated by the bus master. The Start condition is followed by a Device Select Code and Read/Write bit (RW) (as described in Table 3.), terminated by an acknowledge bit.

When writing data to the memory, the device inserts an acknowledge bit during the 9th 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.

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Table 2. Signal Names

	E0, E1, E2		Chip Enable

	SDA		Serial Data

	SCL		Serial Clock

			Write Control
	WC		Write Control

	VCC		Supply Voltage
	VSS		Ground

Power On Reset: VCC 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 VCC has reached the Power On Reset (POR) threshold voltage, and all operations are disabled – the device will not respond to any command. In the same way, when VCC drops from the operating voltage, below the Power On Reset (POR) threshold voltage, all operations are disabled and the device will not respond to any command.

A stable and valid VCC (as defined in Table 9. and Table 10.) must be applied before applying any logic signal.

Figure 3. DIP, SO, TSSOP and UFDFPN

Connections

M24C64

M24C32

E0	1	8	VCC
E1	2	7	WC
E2	3	6	SCL
VSS	4	5	SDA
		AI01845C

Note: See PACKAGE MECHANICAL section for package dimensions, and how to identify pin-1.

M24C64, M24C32

SIGNAL DESCRIPTION

Serial Clock (SCL). This input signal is used to strobe all data in and out of the device. In applications where this signal is used by slave devices to synchronize the bus to a slower clock, the bus master must have an open drain output, and a pull-up resistor must be connected from Serial Clock (SCL) to VCC. (Figure 4. indicates how the value of the pull-up resistor can be calculated). In most applications, though, this method of synchronization is not employed, and so the pull-up resistor is not necessary, provided that the bus master has a push-pull (rather than open drain) output.

Serial Data (SDA). This bi-directional signal is used to transfer data in or out of the device. It is an open drain output that may be wire-OR’ed with other open drain or open collector signals on the bus. A pull up resistor must be connected from Se-

rial Data (SDA) to VCC. (Figure 4. indicates how the value of the pull-up resistor can be calculated).

Chip Enable (E0, E1, E2). These input signals are used to set the value that is to be looked for on the three least significant bits (b3, b2, b1) of the 7- bit Device Select Code. These inputs must be tied to VCC or VSS, to establish the Device Select Code.

Write Control (WC). This input signal is useful for protecting the entire contents of the memory from inadvertent write operations. Write operations are disabled to the entire memory array when Write Control (WC) is driven High. When unconnected, the signal is internally read as VIL, and Write operations are allowed.

When Write Control (WC) is driven High, Device Select and Address bytes are acknowledged, Data bytes are not acknowledged.

Figure 4. Maximum RL Value versus Bus Capacitance (CBUS) for an I2C Bus

Maximum RP value (kΩ)

VCC

SDA

MASTER

CBUS

SCL

fc = 100kHz

fc = 400kHz

CBUS

100

1000

CBUS (pF)

AI01665

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M24C64, M24C32

Figure 5. I2C Bus Protocol

SCL

SDA

START

SDA

STOP

Input

Change

Condition

SCL

SDA

MSB

ACK

START

Condition

SCL

SDA

MSB

ACK

STOP

Condition

AI00792B

Table 3. Device Select Code

Device Type Identifier1

Chip Enable Address2

Device Select Code

Note: 1. The most significant bit, b7, is sent first.

2. E0, E1 and E2 are compared against the respective external pins on the memory device.

Table 4. Most Significant Byte

Table 5. Least Significant Byte

b15

b14

b13

b12

b11

b10

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M24C64, M24C32

MEMORY ORGANIZATION

The memory is organized as shown in Figure 6..

Figure 6. Block Diagram

	WC
	E0	High Voltage
	Control Logic	Generator
	E1	Generator
	E1
	E2
	SCL
	SDA	I/O Shift Register
	Address Register	Data
	and Counter	Register

Y Decoder

1 Page

X Decoder

AI06899

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M24C64, M24C32

DEVICE OPERATION

The device supports the I2C protocol. This is summarized 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 device. 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 driven High. A Stop condition terminates communication 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 successful 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 9th clock pulse period, the receiver pulls Serial

Table 6. Operating Modes

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 only when Serial Clock (SCL) is driven 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 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 I2C 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 device only responds if the Chip Enable Address is the same as the value on the Chip Enable (E0, E1, E2) inputs.

The 8th 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 9th bit time. If the device does not match the Device Select code, it deselects itself from the bus, and goes into Standby mode.

Mode

RW bit

WC 1

Bytes

Initial Sequence

Current Address Read

= 1

START, Device Select, RW

= 0, Address

Random Address Read

START, Device Select, RW

reSTART, Device Select, RW

= 1

Sequential Read

≥ 1

Similar to Current or Random Address Read

Byte Write

VIL

= 0

START, Device Select, RW

Page Write

VIL

≤ 32

= 0

START, Device Select, RW

Note: 1. X = VIH or VIL.

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M24C64, M24C32

Figure 7. Write Mode Sequences with WC=1 (data write inhibited)

ACK

NO ACK

BYTE WRITE

DEV SEL

BYTE ADDR BYTE ADDR

DATA IN

START

R/W

STOP

ACK

NO ACK

PAGE WRITE

DEV SEL

BYTE ADDR

DATA IN 1

DATA IN 2

START

WC (cont'd)

PAGE WRITE (cont'd)

R/W

NO ACK

DATA IN N

STOP

AI01120C

Write Operations

Following a Start condition the bus master sends a Device Select Code with the Read/Write bit (RW) reset to 0. The device acknowledges this, as shown in Figure 8., and waits for two address bytes. The device responds to each address byte with an acknowledge bit, and then waits for the data byte.

Writing to the memory may be inhibited if Write Control (WC) is driven High. Any Write instruction with Write Control (WC) driven High (during a period of time from the Start condition until the end of the two address bytes) will not modify the memory contents, and the accompanying data bytes are not acknowledged, as shown in Figure 7..

Each data byte in the memory has a 16-bit (two byte wide) address. The Most Significant Byte (Table 4.) is sent first, followed by the Least Significant Byte (Table 5.). Bits b15 to b0 form the address of the byte in memory.

When the bus master generates a Stop condition immediately after the Ack bit (in the “10th bit” time

slot), either at the end of a Byte Write or a Page Write, the internal Write cycle is triggered. A Stop condition at any other time slot does not trigger the internal Write cycle.

After the Stop condition, the delay tW, and the successful completion of a Write operation, the device’s internal address counter is incremented automatically, to point to the next byte address after the last one that was modified.

During the internal Write cycle, Serial Data (SDA) is disabled internally, and the device does not respond to any requests.

Byte Write

After the Device Select code and the address bytes, the bus master sends one data byte. If the addressed location is Write-protected, by Write Control (WC) being driven High, the device replies with NoAck, and the location is not modified. If, instead, the addressed location is not Write-protect- ed, the device replies with Ack. The bus master terminates the transfer by generating a Stop condition, as shown in Figure 8..

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