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Part: 24C32
Category:
Memory
Description:
Company: Turbo IC, Inc.
Datasheet: Download 24C32 datasheet File size : 267 kB
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Datasheet text preview:
Turbo IC, Inc.
24C32
CMOS I²C 2-WIRE BUS 32K ELECTRICALLY ERASABLE PROGRAMMABLE ROM 4K X 8 BIT EEPROM
FEATURES : · Extended Power Supply Voltage Single Vcc for Read and Programming (Vcc = 2.7 V to 5.5 V) · Low Power (Isb = 2µa @ 5.5 V) · Extended I²C Bus, 2-Wire Serial Interface · Support Byte Write and Page Write (32 Bytes) · Automatic Page write Operation (maximum 10 ms) Internal Control Timer Internal Data Latches for 32 Bytes · Hardware Data Protection by Write Protect Pin · High Reliability CMOS Technology with EEPROM Cell Endurance : 1,000,000 Cycles Data Retention : 100 Years DESCRIPTION: The Turbo IC 24C32 is a serial 32K EEPROM fabricated with Turbo's proprietary, high reliability, high performance CMOS technology. It's 32K of memory is organized as 4,096 x 8 bits. The memory is configured as 256 pages with each page containing 32 bytes. This device offers significant advantages in low power and low voltage applications. The Turbo IC 24C32 uses the extended I²C addressing protocol and 2-wire serial interface which includes a bidirectional serial data bus synchronized by a clock. It offers a flexible byte write and a faster 32-byte page write. The data in the upper quadrant of memory can be protected by a write protect pin. The Turbo IC 24C32 is assembled in either a 8-pin PDIP or 8-pin SOIC package. Pin #1 (A0), #2 (A1), and #3 (A2) are device address input pins which are hardwired by the user. Pin #4 is the ground (Vss). Pin #5 is the serial data (SDA) pin used for bidirectional transfer of data. Pin #6 is the serial clock (SCL) input pin. Pin #7 is the write protect (WP) input pin, and Pin #8 is the power supply (Vcc) pin. PIN DESCRIPTION All data is serially transmitted in bytes (8 bits) on the SDA bus. To access the Turbo IC 24C32 (slave) for a read or write operation, the controller (master) issues a start condition by pulling SDA from high to low while SCL is high. The master then issues the device address byte which consists of 1010 (A2) (A1) (A0) (R/W). The 4 most significant bits (1010) are a device type code signifying an EEPROM device. The A[2:0] bits represent the input levels on the 3 device address input pins. The read/write bit determines whether to do a read or write operation. After each byte is transmitted, the receiver has to provide an acknowledge by pulling the SDA bus low on the ninth clock cycle. The acknowledge is a handshake signal to the transmitter indicating a successful data transmission.
drain output. A pullup resistor must be connected from SDA to Vcc. SERIAL CLOCK (SCL) The SCL input synchronizes the data on the SDA bus. It is used in conjunction with SDA to define the start and stop conditions. It is also used in conjunction with SDA to transfer data to and from the Turbo IC 24C32.
A0 A1 A2 GND
1 2 3 4
8 7 6 5
VCC WP SCL SDA
A0 A1 A2 GND
1 2 3 4
8 7 6 5
VCC WP SCL SDA
8 pin SOIC
8 pin PDIP
PIN DESCRIPTION DEVICE ADDRESSES (A2-A0) The address inputs are used to define the 3 least significant bits of the 7-bit device address code 1010 (A2) (A1) (A0). These pins can be connected either high or low. A maximum of eight Turbo IC 24C32 can be connected in parallel, each with a unique device address. When these pins are left unconnected, the device addresses are interpreted as zero.
WRITE PROTECT (WP) When the write protect input is connected to Vcc, the upper quadrant of memory (CFF-FFFH) is protected against write operations. For normal write operation, the write protect pin should be grounded. When this pin is left unconnected, WP is interpreted as zero. SERIAL DATA (SDA) SDA is a bidirectional pin used to transfer data in and out of the Turbo IC 24C32. The pin is an open1
Turbo IC, Inc.
24C32
DESCRIPTION (Continued) For a write operation, the master issues a start condition, device address byte, 2 memory address bytes, and then up to 32 data bytes. The Turbo IC 24C32 acknowledges after each byte transmission. To terminate the transmission, the master issues a stop condition by pulling SDA from low to high while SCL is high.
For a read operation, the master issues a start condition and a device address byte. The Turbo IC 24C32 acknowledges, and then transmits a data byte, which is accessed from the EEPROM memory. The master acknowledges, indicating that it requires more data bytes. The Turbo IC 24C32 transmits more data bytes, with the memory address counter automatically incrementing for each data byte, until the master does not acknowledge, indicating that it is terminating the transmission. The master then issues a stop condition.
DEVICE OPERATION: BIDIRECTIONAL BUS PROTOCOL: The Turbo IC 24C32 follows the extended I²C bus protocol. The protocol defines any device that sends data onto the SDA bus as a transmitter, and the receiving device as a receiver. The device controlling the transfer is the master and the device being controlled is the slave. The master always initiates the data transfers, and provides the clock for both transmit and receive operations. The Turbo IC 24C32 acts as a slave device in all applications. Either the master or the slave can take control of the SDA bus, depending on the requirement of the protocol. START/STOP CONDITION AND DATA TRANSITIONS: While SCL clock is high, a high to low transition on the SDA bus is recognized as a START condition which precedes any read or write operation. While SCL clock is high, a low to high transition on the SDA bus is recognized as a STOP condition which terminates the communication and places the Turbo IC 24C32 into standby mode. All other data transitions on the SDA bus must occur while SCL clock is low to ensure proper operation. ACKNOWLEDGE: All data is serially transmitted in bytes (8 bits) on the SDA bus. The acknowledge protocol is used as a handshake signal to indicate successful transmission of a byte of data. The bus transmitter, either the master or the slave (Turbo IC 24C32), releases the bus after sending a byte of data on the SDA bus. The receiver pulls the SDA bus low during the ninth clock cycle to acknowledge the successful transmission of a byte of data. If the SDA is not pulled low during the ninth clock cycle, the Turbo IC 24C32 terminates the data transmission and goes into standby mode. For the write operation, the Turbo IC 24C32 acknowledges after the device address byte, acknowledges after each memory address byte, and acknowledges after each subsequent data byte. For the read operation, the Turbo IC 24C32 acknowledges after the device address byte. Then the Turbo IC 24C32 transmits each subsequent data byte, and the master acknowledges after each data byte transfer, indicating that it requires more data bytes. The Turbo IC 24C32 monitors the SDA bus for the acknowledge. To terminate the transmission, the master does not acknowledge, and then sends a stop condition.
Write Cycle Timing
SCL
SDA
8th BIT WORD n
ACK
t WC
STOP CONDITION
START CONDITION
Note: The write cycle time tWC is the time from a valid stop condition of a write sequence to the end of the internal clear / write cycle.
2
Turbo IC, Inc.
24C32
Data Valid
SDA
SCL
DATA STABLE DATA STABLE DATA CHANGE
Start and Stop Definition
SDA
SCL
START STOP
Output Acknowledge
SCL
1
8
9
DATA IN DATA OUT
START ACKNOWLEDGE
3
Turbo IC, Inc.
24C32
address counter is automatically incremented by one. The stop condition starts the internal EEPROM write cycle only if the stop condition occurs in the clock cycle immediately following the acknowledge (10th clock cycle). All inputs are disabled until the completion of the write cycle. If the WP pin is high (1) and the memory address is within the upper quadrant (CFF-FFFH) of memory, then the stop condition does not start the internal write cycle, and the Turbo IC 24C32 is immediately ready for the next command. POLLING ACKNOWLEDGE: During the internal write cycle of a write operation in the Turbo IC 24C32, the completion of the write cycle can be detected by polling acknowledge. The master starts acknowledge polling by issuing a start condition, then followed by the device address byte 1010 (A2) (A1) (A0) 0. If the internal write cycle is finished, the Turbo IC 24C32 acknowledges by pulling the SDA bus low. If the internal write cycle is still ongoing, the Turbo IC 24C32 does not acknowledge because it's inputs are disabled. Therefore, the device will not respond to any command. By using polling acknowledge, the system delay for write operations can be reduced. Otherwise, the system needs to wait for the maximum internal write cycle time, tWC, given in the spec. POWER ON RESET: The Turbo IC 24C32 has a Power On Reset circuit (POR) to prevent data corruption and accidental write operations during power up. On power up, the internal reset signal is on and the Turbo IC 24C32 will not respond to any command until the VCC voltage has reached the POR threshold value.
DEVICE ADDRESSING: Following the start condition, the master will issue a device address byte consisting of 1010 (A2) (A1) (A0) (R/W) to access the selected Turbo IC 24C32 for a read or write operation. The A[2:0] bits must match with the address input pins of the selected Turbo IC 24C32. If there is a match, the selected Turbo IC 24C32 acknowledges during the ninth clock cycle by pulling the SDA bus low. If there is no match, the Turbo IC 24C32 does not acknowledge during the ninth clock cycle and goes into standby mode. The (R/W) bit is a high (1) for read and low (0) for write. DATA INPUT DURING WRITE OPERATION: During the write operation, the Turbo IC 24C32 latches the SDA bus signal on the rising edge of the SCL clock. DATA OUTPUT DURING READ OPERATION: During the read operation, the Turbo IC 24C32 serially shifts the data onto the SDA bus on the falling edge of the SCL clock. MEMORY ADDRESSING: The memory address is sent by the master in the form of 2 memor y address bytes. The memory address bytes can only be sent as part of a write operation. The most significant address byte XXX (B11) (B10) (B9) (B8) is sent first, where X represents "don't care". Then the least significant address byte (B7) (B6) (B5) (B4) (B3) (B2) (B1) (B0) is sent last. BYTE WRITE OPERATION: The master initiates the byte write operation by issuing a star t condition, followed by the device address byte 1010 (A2) (A1) (A0) 0, followed by 2 memory address bytes, followed by one data byte, followed by an acknowledge, then a stop condition. After each byte transfer, the Turbo IC 24C32 acknowledges the successful data transmission by pulling the SDA bus low. The stop condition starts the internal EEPROM write cycle, and all inputs are disabled until the completion of the write cycle. If the WP pin is high (1) and the memor y address is within the upper quadrant (1800-1FFFH) of memory, then the stop condition does not start the internal write cycle and the Turbo IC 24C32 is immediately ready for the next command. PAGE WRITE OPERATION: The master initiates the page write operation by issuing a star t condition, followed by the device address byte 1010 (A2) (A1) (A0) 0, followed by 2 memory address bytes, followed by up to 32 data bytes, followed by an acknowledge, then a stop condition. After each byte transfer, the Turbo IC24C64 acknowledges the successful data transmission by pulling SDA low. After each data byte transfer, the memory
4
Turbo IC, Inc.
24C32
Device Address
1 MSB
0
1
0
A2
A1
A0
R/W LSB
Byte Write
S T A R T SDA LINE M S B
DEVICE ADDRESS
W R I T E
FIRST WORD ADDRESS ** **
SECOND WORD ADDRESS
DATA
S T O P
L RA S/C B WK
M S B
A C K
LA SC BK
A C K
Page Write
S T A R T SDA LINE M S B
DEVICE ADDRESS
W R I T FIRST SECOND E WORD ADDRESS (n) WORD ADDRESS (n) ** ** L RA S/C B WK M S B A C K LA SC BK
DATA (n)
A C K
// //
DATA (n + x)
S T O P
A C K
* = Don't care bits
5
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