NM34C02 2K-Bit Standard 2-Wire Bus Interface Designed with Permanent Write-Protection for First 128 Bytes for Serial Presence Detect Application on Memory Modules Features General Description The NM34C02 is 2048 bits of CMOS non-volatile electrically erasable memory. It is designed to support Serial Presence Detect circuitry in memory modules. This communications protocol uses CLOCK (SCL) and DATA I/O (SDA) lines to synchronously clock data between the master (for example a microprocessor) and the slave EEPROM device(s). ■ Extended Operating Voltage: 2.7V-5.5V ■ Write-Protection for first 128 bytes ■ 200 µA active current typical – 10 µA standby current typical – 1.0 µA standby current typical (L) – 0.1 µA standby current typical (LZ) The contents of the non-volatile memory allows the CPU to determine the capacity of the module and the electrical characteristics of the memory devices it contains. This will enable "plug and play" capability as the module is read and PC main memory resources utilized through the memory controller. ■ IIC compatible interface – Provides bidirectional data transfer protocol ■ Sixteen byte page write mode – Minimizes total write time per byte The first 128 bytes of the memory of the NM34C02 can be permanently Write Protected by writing to the "WRITE PROTECT" Register. Write Protect implementation details are described under the section titled Addressing the WP Register. ■ Self timed write cycle - Typical write cycle time of 6ms ■ Endurance: 1,000,000 data changes ■ Data retention greater than 40 years The NM34C02 is available in a JEDEC standard TSSOP package for low profile memory modules for systems requiring efficient space utilization such as in a notebook computer. Two options are available: L - Low Voltage and LZ - Low Power, allowing the part to be used in systems where battery life is of primary importance. ■ Packages available: 8-pin TSSOP and 8-pin SO Block Diagram VCC VSS H.V. GENERATION TIMING &CONTROL START CYCLE START STOP LOGIC SDA CONTROL LOGIC SLAVE ADDRESS REGISTER & COMPARATOR SCL 16 XDEC LOAD A2 A1 A0 E2PROM ARRAY 16 x 16 x 8 INC WORD ADDRESS COUNTER 0/1/2/3 4 16 4 R/W YDEC Device Address Bits Write Protect Register 8 CK DATA REGISTER DIN DOUT DS012821-1 © 1999 Fairchild Semiconductor Corporation NM34C02 Rev. D.2 1 www.fairchildsemi.com NM34C02 2K-Bit Standard 2-Wire Bus Interface March 1999 NM34C02 2K-Bit Standard 2-Wire Bus Interface Connection Diagram SO (M8) and TSSOP (MT8) Package A0 1 8 VCC A1 2 7 NC A2 3 6 SCL VSS 4 5 SDA NM34C02 DS012821-2 Top View See Package Number M08A and MTC08 Pin Names A0,A1,A2 Device Address Inputs VSS Ground SDA Data I/O SCL Clock Input NC No Connection VCC Power Supply Ordering Information NM34C02 XX X X Package M8 = 8 pin SOIC MT8 = 8 pin TSSOP Temperature Range Blank = 0°C to +70°C E = -40°C to +85°C Voltage Range Blank = 4.5V to 5.5V L = 2.7V to 4.5V LZ = 2.7V to 4.5V and < 1µA standby current Device 2K IIC Serial EEPROM DS012821-21 2 NM34C02 Rev. D.2 www.fairchildsemi.com Operating Conditions Absolute Maximum Ratings Ambient Storage Temperature Ambient Operating Temperature NM34C02 NM34C02E –65°C to +150°C All Input or Output Voltages with Respect to Ground 6.5V to –0.3V Lead Temperature (Soldering, 10 seconds) Positive Power Supply NM34C02 NM34C02L NM34C02LZ +300°C ESD Rating 0°C to +70°C -40°C to +85°C 2000V min. 4.5V to 5.5V 2.7V to 4.5V 2.7V to 4.5V Standard VCC (4.5V to 5.5V) DC Electrical Characteristics Symbol Parameter Test Conditions Min Limits Typ (Note 1) Max Units ICCA Active Power Supply Current fSCL = 100 kHz 0.2 1.0 mA ISB Standby Current VIN = GND or VCC 10 50 µA ILI Input Leakage Current VIN = GND to VCC 0.1 1 µA ILO Output Leakage Current VOUT = GND to VCC 0.1 1 µA VIL Input Low Voltage –0.3 VCC x 0.3 V VIH Input High Voltage VCC x 0.7 VCC + 0.5 V VOL Output Low Voltage 0.4 V IOL = 3 mA Low VCC (2.7V to 5.5V) DC Electrical Characteristics Symbol Parameter Test Conditions Min Limits Typ (Note 1) Max Units ICCA Active Power Supply Current fSCL = 100 kHz 0.2 1.0 mA ISB Standby Current for L Standby Current for LZ VIN = GND or VCC VIN = GND or VCC 1 0.1 10 1 µA µA ILI Input Leakage Current VIN = GND to VCC 0.1 1 µA ILO Output Leakage Current VOUT = GND to VCC 0.1 1 µA VIL Input Low Voltage –0.3 VCC x 0.3 V VIH Input High Voltage VCC x 0.7 VCC + 0.5 V VOL Output Low Voltage 0.4 V IOL = 3 mA Capacitance TA = +25°C, f = 100/400 KHz, VCC = 5V (Note 2) Symbol Test Conditions Max Units CI/O Input/Output Capacitance (SDA) VI/O = 0V 8 pF CIN Input Capacitance (A0, A1, A2, SCL) VIN = 0V 6 pF Note 1: Typical values are TA = 25°C and nominal supply voltage (5V). Note 2: This parameter is periodically sampled and not 100% tested. 3 NM34C02 Rev. D.2 www.fairchildsemi.com NM34C02 2K-Bit Standard 2-Wire Bus Interface Product Specifications Input Pulse Levels VCC x 0.1 to VCC x 0.9 Input Rise and Fall Times 10 ns Input & Output Timing Levels VCC x 0.5 Output Load 1 TTL Gate and CL = 100 pF Read and Write Cycle Limits (Standard and Low VCC Range 2.7V - 4.5V) Symbol fSCL TI Parameter 100 KHz Min Max 400 KHz Min Max Units SCL Clock Frequency 100 400 KHz Noise Suppression Time Constant at SCL, SDA Inputs (Minimum VIN Pulse width) 100 50 ns 0.9 µs tAA SCL Low to SDA Data Out Valid 0.3 tBUF Time the Bus Must Be Free before a New Transmission Can Start 4.7 1.3 µs Start Condition Hold Time 4.0 0.6 µs tLOW Clock Low Period 4.7 1.5 µs tHIGH Clock High Period 4.0 0.6 µs tSU:STA Start Condition Setup Time (for a Repeated Start Condition) 4.7 0.6 µs tHD:DAT Data in Hold Time 0 0 µs tSU:DAT Data in Setup Time 250 100 ns tHD:STA tR SDA and SCL Rise Time tF SDA and SCL Fall Time tSU:STO tDH tWR (Note 3) 3.5 0.1 1 300 0.3 µs 300 ns Stop Condition Setup Time 4.7 0.6 µs Data Out Hold Time 300 50 ns Write Cycle Time - NM34C02 - NM34C02L, NM34C02LZ 10 15 10 15 ms Note 3: The write cycle time (tWR) is the time from a valid stop condition of a write sequence to the end of the internal erase/program cycle. During the write cycle, the NM34C02 bus interface circuits are disabled, SDA is allowed to remain high per the bus-level pull-up resistor, and the device does not respond to its slave address. 4 NM34C02 Rev. D.2 www.fairchildsemi.com NM34C02 2K-Bit Standard 2-Wire Bus Interface AC Conditions of Test tR tF tHIGH tLOW tLOW SCL ,, tSU:STA tHD:DAT tHD:STA SDA tSU:DAT tSU:STO IN tBUF tAA tDH SDA OUT DS012821-4 Background Information (IIC Bus) DEFINITIONS As mentioned, the IIC bus allows synchronous bidirectional communication between Transmitter/Receiver using the SCL (clock) and SDA (Data I/O) lines. All communication must be started with a valid START condition, concluded with a STOP condition and acknowledged by the Receiver with an ACKNOWLEDGE condition. BYTE 8 bits of data PAGE 16 sequential addresses (one byte each) that may be programmed during a 'Page Write' programming cycle In addition, since the IIC bus is designed to support other devices such as RAM, EPROMs, etc., a device type identifier string must follow the START condition. For EEPROMs, this 4-bit string is 1010. Also refer the Addressing the WP Register section. PAGE BLOCK 2,048 (2K) bits organized into 16 pages of addressable memory. (8 bits) x (16 bytes) x (16 pages) = 2,048 bits MASTER Any IIC device CONTROLLING the transfer of data (such as a microprocessor) As shown below, although the EEPROMs on the IIC bus may be configured in any manner required, the total memory addressed can not exceed 16K (16,384 bits) on the Standard IIC protocol. EEPROM memory address programming is controlled by 2 methods: SLAVE • Hardware configuring the A0, A1, and A2 pins (Device Address pins) with pull-up or pull-down resistors. All unused pins must be grounded (tied to VSS). Device being controlled (EEPROMs are always considered Slaves) TRANSMITTER • Software addressing the required PAGE BLOCK within the device memory array (as sent in the Slave Address string). Addressing an EEPROM memory location involves sending a command string with the following information: Device currently SENDING data on the bus (may be either a Master or Slave). RECEIVER Device currently receiving data on the bus (Master or Slave) [DEVICE TYPE]—[DEVICE ADDRESS]—[PAGE BLOCK ADDRESS]—[BYTE ADDRESS] Example of 16K of Memory on 2-Wire Bus VCC SDA SCL VCC VCC VCC NM34C02L NM24C02 NM24C04 NM24C08 A0 A1 A2 VSS A0 A1 A2 VSS A0 A1 A2 VSS A0 A1 A2 VSS To VCC or VSS Note: VCC To VCC or VSS To VCC or VSS To VCC or VSS DS012821-5 The SDA pull-up resistor is required due to the open-drain/open collector output of IIC bus devices The SCL pull-up resistor is recommended because of the normal SCL line inactive 'high' state. It is recommended that the total line capacitance be less than 400pF. Specific timing and addressing considerations are described in greater detail in the following sections. 5 NM34C02 Rev. D.2 www.fairchildsemi.com NM34C02 2K-Bit Standard 2-Wire Bus Interface Bus Timing Address Pins A0 A1 A2 NM34C02 ADR ADR ADR Memory Size Number of Page Blocks 2048 Bits 1 Pin Descriptions Start Condition Serial Clock (SCL) All commands are preceded by the start condition, which is a HIGH to LOW transition of SDA when SCL is HIGH. The NM34C02 continuously monitors the SDA and SCL lines for the start condition and will not respond to any command until this condition has been met. The SCL input is used to clock all data into and out of the device. Serial Data (SDA) SDA is a bidirectional pin used to transfer data into and out of the device. It is an open drain output and may be wire–ORed with any number of open drain or open collector outputs. Stop Condition All communications are terminated by a stop condition, which is a LOW to HIGH transition of SDA when SCL is HIGH. The stop condition is also used by the NM34C02 to place the device in the standby power mode. Device Operation Inputs (A0, A1, A2) Device address pins A0, A1, and A2 are connected to VCC or VSS to configure the EEPROM chip address. Table A shows the active pins across the NM34C02 device family. ACKNOWLEDGE Acknowledge is a software convention used to indicate successful data transfers. The transmitting device, either master or slave, will release the bus after transmitting eight bits. Table 1. Device NM34C02L A0 A1 A2 ADR ADR ADR Effects of Addresses During the ninth clock cycle the receiver will pull the SDA line to LOW to acknowledge that it received the eight bits of data. Refer to Figure 3. 8 devices max. Device Operation The NM34C02 device will always respond with an acknowledge after recognition of a start condition and its slave address. If both the device and a write operation have been selected, the NM34C02 will respond with an acknowledge after the receipt of each subsequent eight bit byte. The NM34C02 supports a bidirectional bus oriented protocol. The protocol defines any device that sends data onto the bus as a transmitter and the receiving device as the receiver. The device controlling the transfer is the master and the device that is controlled is the slave. The master will always initiate data transfers and provide the clock for both transmit and receive operations. Therefore, the NM34C02 will be considered a slave in all applications. In the Read mode the NM34C02 slave will transmit eight bits of data, release the SDA line and monitor the line for an acknowledge. If an acknowledge is detected and no stop condition is generated by the master, the slave will continue to transmit data. If an acknowledge is not detected, the slave will terminate further data transmissions and await the stop condition to return to the standby power mode. Clock and Data Conventions Data states on the SDA line can change only during SCL LOW. SDA state changes during SCL HIGH are reserved for indicating start and stop conditions. Refer to Figures 1 and 2. 6 NM34C02 Rev. D.2 www.fairchildsemi.com NM34C02 2K-Bit Standard 2-Wire Bus Interface Device SCL SDA 8th BIT ACK WORD n tWR STOP CONDITION START CONDITION DS012821-6 SCL DATA CHANGE DATA STABLE SDA DS012821-7 Data Validity (Figure 1). SCL START CONDITION STOP CONDITION SDA DS012821-8 Start and Stop Definition (Figure 2). SCL FROM MASTER 1 8 9 DATA OUTPUT FROM TRANSMITTER DATA OUTPUT FROM RECEIVER START ACKNOWLEDGE Acknowledge Responses from Receiver (Figure 3). DS012821-9 Device Addressing Following a start condition the master must output the address of the slave it is accessing. The most significant four bits of the slave address are those of the device type identifier (see Figure 4). This is fixed as 1010 for all EEPROM devices. All IIC EEPROMs use an internal protocol that defines a PAGE BLOCK size of 2K bits (for Byte addresses 00 through FF). 7 NM34C02 Rev. D.2 www.fairchildsemi.com NM34C02 2K-Bit Standard 2-Wire Bus Interface Write Cycle Timing Device Type Identifier 1 0 1 instead of terminating the write cycle after the first data byte is transferred, the master can transmit up to fifteen more bytes. After the receipt of each byte, the NM34C02 will respond with an acknowledge. Device Address 0 A2 A1 A0 R/W NM34C02 After the receipt of each byte, the internal address counter increments to the next address and the next SDA data is accepted. If the master should transmit more than sixteen bytes prior to generating the stop condition, the address counter will 'roll over' and the previously written data will be overwritten. As with the byte write operation, all inputs are disabled until completion of the internal write cycle. Refer to Figure 6 for the address, acknowledge, and data transfer sequence. (LSB) DS012821-10 Slave Addresses (Figure 4). Refer to the following table for Slave Address string details: Device A0 NM34C02 A A1 A2 A A Page Blocks Page Block Addresses 1 (2K) (None) Acknowledge Polling Once the stop condition is issued to indicate the end of the host’s write operation the NM34C02 initiates the internal write cycle. ACK polling can be initiated immediately. This involves issuing the start condition followed by the slave address for a write operation. If the NM34C02 is still busy with the write operation no ACK will be returned. If the NM34C02 has completed the write operation an ACK will be returned and the host can then proceed with the next read or write operation. Write Operations The last bit of the slave address defines whether a write or read condition is requested by the master. A '1' indicates that a read operation is to be executed, and a '0' initiates the write mode. A simple review: After the NM34C02 recognizes the start condition, the devices interfaced to the IIC bus wait for a slave address to be transmitted over the SDA line. If the transmitted slave address matches an address of one of the devices, the designated slave pulls the line LOW with an acknowledge signal and awaits further transmissions. Software Write Protect Write protection on the NM34C02 protects the first 128 bytes of the EEPROM memory. Write protection is implemented through a seperate register called the WRITE PROTECT (WP) Register and writing to this WP register permanently WRITE protects the memory. This WP register is a "one-time-only-write" register. Once this register is written, it cannot be erased. After the first WRITE to this register, all future access' to this register are ignored as if an invalid IIC cycle occured. To write protect, the user must perform a byte write to the WP register. This will permanently disable programming to the first 128 bytes of memory. Byte Write For a write operation a second address field is required which is a byte address that is comprised of eight bits and provides access to any one of the 256 bytes in the selected page block of memory. Upon receipt of the byte address the NM34C02 responds with an acknowledge and waits for the next eight bits of data, again, responding with an acknowledge. The master then terminates the transfer by generating a stop condition, at which time the NM34C02 begins the internal write cycle to the nonvolatile memory. While the internal write cycle is in progress the NM34C02 inputs are disabled, and the device will not respond to any requests from the master. Refer to Figure 5 for the address, acknowledge and data transfer sequence. Addressing the WP Register Addressing the WP register is very similar to accessing any memory array with the following difference: Instead of the conventional "1010" IIC device address, the unused IIC device address "0110" is used to access just the WP register. Device address "1010" will be used for all the typical memory array access. With this difference in place, accessing the WP register is same as a typical IIC byte write cycle as described under "Write Operations" section. All timing information and waveform details remain the same. The "Byte Address" and the "Data" fields of the Byte write cycle serve as place holders and can be of any value (Don't Care). Refer to Figure 7. Page Write The NM34C02 is capable of a sixteen byte page write operation. It is initiated in the same manner as the byte write operation; but 8 NM34C02 Rev. D.2 www.fairchildsemi.com NM34C02 2K-Bit Standard 2-Wire Bus Interface Device Addressing (Continued) Bus Activity: Master S T A R T SLAVE ADDRESS WORD ADDRESS S T O P DATA SDA Line A C K A C K A C K DS012821-14 Byte Write (Figure 5). Bus Activity: Master S T A R T SLAVE ADDRESS BYTE ADDRESS (n) DATA n DATA n + 1 S T O P DATA n + 15 SDA Line A C K A C K A C K A C K A C K DS012821-15 Page Write (Figure 6). Bus Activity: Master S T A R T SLAVE ADDRESS BYTE ADDRESS S T O P DATA SDA Line Bus Activity: DEVICE ADDRESS A C K DON'T CARE A C K DON'T CARE A C K DS012821-16 WP Register Write (Figure 7). Read Operations slave address, R/W bit set to zero, and then the word address to be read. After the Slave word address acknowledge, the master immediately reissues the start condition and the slave address with the R/W bit set to one. This will be followed by an acknowledge from the NM34C02 and then by the eight bit word. The master will not acknowledge the transfer but does generate the stop condition, and therefore the NM34C02 discontinues transmission. Refer to Figure 9 for the address, acknowledge and data transfer sequence. Read operations are initiated in the same manner as write operations, with the exception that the R/W bit of the slave address is set to a one. There are three basic read operations: current address read, random read, and sequential read. CURRENT ADDRESS READ Internally the NM34C02 contains an address counter that maintains the address of the last word accessed, incremented by one. Therefore, if the last access (either a read or write) was to address n, the next read operation would access data from address n + 1. Upon receipt of the slave address with R/W set to one, the NM34C02 issues an acknowledge and transmits the data byte. The master will not acknowledge the transfer but does generate a stop condition, and therefore the NM34C02 discontinues transmission. Refer to Figure 8 for the sequence of address, acknowledge and data transfer. SEQUENTIAL READ Sequential reads can be initiated as either a current address read or random access read. The first word is transmitted in the same manner as the other read modes; however, the master now responds with an acknowledge, indicating it requires additional data. The NM34C02 continues to output data for each acknowledge received. The read operation is terminated by the master not responding with an acknowledge or by generating a stop condition. RANDOM READ Random read operations allow the master to access any memory location in a random manner. Prior to issuing the slave address with the R/W bit set to one, the master must first perform a “dummy” write operation. The master issues the start condition, The data output is sequential, with the data from address n followed by the data from n + 1. The address counter for read 9 NM34C02 Rev. D.2 www.fairchildsemi.com NM34C02 2K-Bit Standard 2-Wire Bus Interface Write Protect Scheme (Continued) operations increments all word address bits, allowing the entire memory contents to be serially read during one operation. After the entire memory has been read, the counter 'rolls over' and the NM34C02 continues to output data for each acknowledge received. Refer to Figure 10 for the address, acknowledge, and data transfer sequence. Bus Activity: Master S T A R T S T O P SLAVE ADDRESS SDA Line A C K DATA DS012821-17 Current Address Read (Figure 8). Bus Activity: Master S T A R T SLAVE ADDRESS S T A R T BYTE ADDRESS S T O P SLAVE ADDRESS S SDA Line A C K A C K A C K DATA n DS012821-18 Random Read (Figure 9). Bus Activity: Master A C K Slave Address A C K S T O P A C K SDA Line A C K Data n Data n +1 Data n + 2 Data n + x DS012821-19 Sequential Read (Figure 10). VCC SDA SCL Master Transmitter/ Receiver Note: Slave Receiver Slave Transmitter/ Receiver Master Transmitter Master Transmitter/ Receiver Due to open drain configuration of SDA, a bus-level resistor is called for (Typical value = 4.7Ω) DS012821-20 Typical System Configuration (Figure 11). 10 NM34C02 Rev. D.2 www.fairchildsemi.com NM34C02 2K-Bit Standard 2-Wire Bus Interface Read Operations (Continued) NM34C02 2K-Bit Standard 2-Wire Bus Interface Physical Dimensions inches (millimeters) unless otherwise noted 0.189 - 0.197 (4.800 - 5.004) 8 7 6 5 0.228 - 0.244 (5.791 - 6.198) 1 2 3 4 Lead #1 IDENT 0.010 - 0.020 x 45° (0.254 - 0.508) 0.0075 - 0.0098 (0.190 - 0.249) Typ. All Leads 0.150 - 0.157 (3.810 - 3.988) 8° Max, Typ. All leads 0.04 (0.102) All lead tips 0.053 - 0.069 (1.346 - 1.753) 0.004 - 0.010 (0.102 - 0.254) Seating Plane 0.014 (0.356) 0.016 - 0.050 (0.406 - 1.270) Typ. All Leads 0.050 (1.270) Typ 0.014 - 0.020 Typ. (0.356 - 0.508) 8-Pin Molded Small Outline Package (M8) Order Number NM34C02LM8/LZM8 Package Number M08A 11 NM34C02 Rev. D.2 www.fairchildsemi.com 0.114 - 0.122 (2.90 - 3.10) 8 5 (4.16) Typ (7.72) Typ 0.169 - 0.177 (4.30 - 4.50) 0.246 - 0.256 (6.25 - 6.5) (1.78) Typ (0.42) Typ 0.123 - 0.128 (3.13 - 3.30) (0.65) Typ 1 Land pattern recommendation 4 Pin #1 IDENT 0.0433 Max (1.1) 0.0256 (0.65) Typ. 0.0035 - 0.0079 See detail A 0.002 - 0.006 (0.05 - 0.15) 0.0075 - 0.0098 (0.19 - 0.30) Gage plane 0°-8° DETAIL A Typ. Scale: 40X 0.020 - 0.028 (0.50 - 0.70) Seating plane 0.0075 - 0.0098 (0.19 - 0.25) Notes: Unless otherwise specified 1. Reference JEDEC registration MO153. Variation AA. Dated 7/93 8-Pin Molded TSSOP, JEDEC (MT8) Order Number NM34C02LMT8/LZMT8 Package Number MTC08 Life Support Policy Fairchild's products are not authorized for use as critical components in life support devices or systems without the express written approval of the President of Fairchild Semiconductor Corporation. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. Fairchild Semiconductor Americas Customer Response Center Tel. 1-888-522-5372 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. Fairchild Semiconductor Europe Fax: +44 (0) 1793-856858 Deutsch Tel: +49 (0) 8141-6102-0 English Tel: +44 (0) 1793-856856 Français Tel: +33 (0) 1-6930-3696 Italiano Tel: +39 (0) 2-249111-1 Fairchild Semiconductor Hong Kong 8/F, Room 808, Empire Centre 68 Mody Road, Tsimshatsui East Kowloon. Hong Kong Tel; +852-2722-8338 Fax: +852-2722-8383 Fairchild Semiconductor Japan Ltd. 4F, Natsume Bldg. 2-18-6, Yushima, Bunkyo-ku Tokyo, 113-0034 Japan Tel: 81-3-3818-8840 Fax: 81-3-3818-8841 Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and Fairchild reserves the right at any time without notice to change said circuitry and specifications. 12 NM34C02 Rev. D.2 www.fairchildsemi.com NM34C02 2K-Bit Standard 2-Wire Bus Interface Physical Dimensions inches (millimeters) unless otherwise noted