24LCS22A 2K VESA® E-EDID™ Serial EEPROM • Single Supply with Operation down to 2.5V • Supports Enhanced EDID™ (E-EDID™) 1.3 • Completely Implements DDC1™/DDC2™ Interface for Monitor Identification, including Recovery to DDC1 • 2 Kbit Serial EEPROM Low-Power CMOS Technology: - 1 mA active current, typical - 10 μA standby current, typical at 5.5V • 2-Wire Serial Interface Bus, I2C™ Compatible • 100 kHz (2.5V) and 400 kHz (5V) Compatibility • Self-Timed Write Cycle (including Auto-Erase) • Hardware Write-Protect Pin • Page Write Buffer for up to Eight Bytes • 1,000,000 Erase Write Cycles • Data Retention >200 years • ESD Protection >4000V • 8-pin PDIP and SOIC Packages • Available Temperature Ranges: - Industrial (I) -40°C to +85°C • Pb-Free and RoHS Compliant Package Types PDIP/SOIC *NC 1 *NC 2 WP 3 VSS 4 24LCS22A Features: 8 VCC 7 VCLK 6 SCL 5 SDA * Pins labeled ‘NC’ have no internal connection Block Diagram WP HV Generator I/O Control Logic Memory Control Logic XDEC EEPROM Array Page Latches Description: The Microchip Technology Inc. 24LCS22A is a 256 x 8-bit dual-mode Electrically Erasable PROM (EEPROM). This device is designed for use in applications requiring storage and serial transmission of configuration and control information. Two modes of operation have been implemented: Transmit-Only mode (1 Kbit) and Bidirectional mode (2 Kbit). Upon power-up, the device will be in the Transmit-Only mode, sending a serial bit stream of the memory array from 00h to 7Fh, clocked by the VCLK pin. A valid high-to-low transition on the SCL pin will cause the device to enter the Transition mode, and look for a valid control byte on the I2C bus. If it detects a valid control byte from the master, it will switch into Bidirectional mode, with byte selectable read/write capability of the entire 2K memory array using SCL. If no control byte is received, the device will revert to the Transmit-Only mode after it receives 128 consecutive VCLK pulses while the SCL pin is idle. The 24LCS22A is available in standard 8-pin PDIP and SOIC packages. The 24LCS22A features a flexible write-protect pin which is enabled by writing to address 7Fh (usually the checksum in VESA® applications. © 2009 Microchip Technology Inc. SDA SCL YDEC VCLK Vcc Sense Amp. R/W Control Vss DS21682E-page 1 24LCS22A 1.0 ELECTRICAL CHARACTERISTICS Absolute Maximum Ratings(†) VCC .............................................................................................................................................................................7.0V All inputs and outputs w.r.t. VSS ......................................................................................................... -0.6V to VCC +1.0V Storage temperature ...............................................................................................................................-65°C to +150°C Ambient temperature with power applied ................................................................................................-40°C to +125°C ESD protection on all pins ......................................................................................................................................................≥ 4 kV † Notice: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operational listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability. TABLE 1-1: DC CHARACTERISTICS Vcc = +2.5V to 5.5V Industrial (I): TA = -40°C to +85°C DC CHARACTERISTICS Param. No. Sym Characteristic Min. Max. Units Test Conditions SCL and SDA pins: D1 VIH High-level input voltage 0.7 VCC — V D2 VIL Low-level input voltage — 0.3 VCC V Input levels on VCLK pin: D3 VIH High-level input voltage 2.0 — V VCC ≥ 2.7V (Note) D4 VIL Low-level input voltage — 0.2 VCC V VCC ≤ 2.7V (Note) D5 VHYS Hysteresis of Schmitt Trigger Inputs .05 VCC — V (Note) D6 VOL1 Low-level output voltage — 0.4 V IOL = 3 mA, VCC = 2.5V (Note) D7 VOL2 Low-level output voltage — 0.6 V IOL = 6 mA, VCC = 2.5V D8 ILI Input leakage current — ±1 μA VIN = 0.1V to VCC D9 ILO Output leakage current — ±1 μA VOUT = 0.1V to VCC D10 CIN, COUT Pin capacitance (all inputs/outputs) — 10 pF VCC = 5.0V (Note) TA = 25°C, FCLK = 1 MHz Operating current: D10 ICC WRITE Operating current — 3 mA VCC = 5.5V, D11 ICC READ Operating current — 1 mA VCC = 5.5V, SCL = 400 kHz D12 ICCS Standby current — — 30 100 μA μA VCC = 3.0V, SDA = SCL = VCC VCC = 5.5V, SDA = SCL = VCC VCLK = VSS Note: This parameter is periodically sampled and not 100% tested. DS21682E-page 2 © 2009 Microchip Technology Inc. 24LCS22A TABLE 1-2: AC CHARACTERISTICS Vcc = +2.5V to 5.5V Industrial (I): TA = -40°C to +85°C AC CHARACTERISTICS Param. No. Sym Parameter Min Max Units Conditions 1 FCLK Clock frequency — — 100 400 kHz 2.5V ≤ VCC ≤ 5.5V 4.5V ≤ VCC ≤ 5.5V 2 THIGH Clock high time 4000 600 — — ns 2.5V ≤ VCC ≤ 5.5V 4.5V ≤ VCC ≤ 5.5V 3 TLOW Clock low time 4700 1300 — — ns 2.5V ≤ VCC ≤ 5.5V 4.5V ≤ VCC ≤ 5.5V 4 TR SDA and SCL rise time — — 1000 300 ns 2.5V ≤ VCC ≤ 5.5V (Note 1) 4.5V ≤ VCC ≤ 5.5V (Note 1) 5 TF SDA and SCL fall time — — 300 300 ns (Note 1) 6 THD:STA Start condition hold time 4000 600 — — ns 2.5V ≤ VCC ≤ 5.5V 4.5V ≤ VCC ≤ 5.5V 7 TSU:STA Start condition setup time 4700 600 — — ns 2.5V ≤ VCC ≤ 5.5V 4.5V ≤ VCC ≤ 5.5V 8 THD:DAT Data input hold time 0 0 — — ns (Note 2) 9 TSU:DAT Data input setup time 250 100 — — ns 2.5V ≤ VCC ≤ 5.5V 4.5V ≤ VCC ≤ 5.5V 10 TSU:STO Stop condition setup time 4000 600 — — ns 2.5V ≤ VCC ≤ 5.5V 4.5V ≤ VCC ≤ 5.5V 11 TAA Output valid from clock (Note 2) — — 3500 900 ns 2.5V ≤ VCC ≤ 5.5V 4.5V ≤ VCC ≤ 5.5V 12 TBUF Bus free time: Time the bus must be free before a new transmission can start 4700 1300 — — ns 2.5V ≤ VCC ≤ 5.5V 4.5V ≤ VCC ≤ 5.5V 13 TOF Output fall time from VIH minimum to VIL maximum — 20+0.1CB 250 250 ns 2.5V ≤ VCC ≤ 5.5V (Note 1) 4.5V ≤ VCC ≤ 5.5V (Note 1) 14 TSP Input filter spike suppression (SDA and SCL pins) — — 50 50 ns (Notes 1 and 3) 15 TWR Write cycle time (byte or page) — — 10 10 ms 16 TVAA Output valid from VCLK — — 2000 1000 ns 17 TVHIGH VCLK high time 4000 600 — — ns 18 TVLOW VCLK low time 4700 1300 — — ns 19 TVHST VCLK setup time 0 0 — — ns 20 TSPVL VCLK hold time 4000 600 — — ns 21 TVHZ Mode transition time — — 1000 500 ns 22 TVPU Transmit-only power-up time 0 0 — — ns 23 TSPV Input filter spike suppression (VCLK pin) — — 100 100 ns 24 — Endurance 1M — cycles Note 1: 2: 3: 4: 25°C, VCC = 5.0V, Block mode (Note 4) Not 100% tested. CB = total capacitance of one bus line in pF. As a transmitter, the device must provide an internal minimum delay time to bridge the undefined region (minimum 300 ns) of the falling edge of SCL to avoid unintended generation of Start or Stop conditions. The combined TSP and VHYS specifications are due to Schmitt Trigger inputs which provide improved noise spike suppression. This eliminates the need for a TI specification for standard operation. This parameter is not tested but established by characterization. For endurance estimates in a specific application, please consult the Total Endurance™ Model which can be obtained from Microchip’s web site at www.microchip.com. © 2009 Microchip Technology Inc. DS21682E-page 3 24LCS22A 2.0 FUNCTIONAL DESCRIPTION be initialized prior to valid data being sent in the Transmit-Only mode (Section 2.2 “Initialization Procedure”). In this mode, data is transmitted on the SDA pin in 8-bit bytes, with each byte followed by a ninth, Null bit (Figure 2-1). The clock source for the TransmitOnly mode is provided on the VCLK pin, and a data bit is output on the rising edge on this pin. The eight bits in each byte are transmitted Most Significant bit first. Each byte within the memory array will be output in sequence. After address 7Fh in the memory array is transmitted, the internal Address Pointers will wrap around to the first memory location (00h) and continue. The Bidirectional mode clock (SCL) pin must be held high for the device to remain in the Transmit-Only mode. The 24LCS22A is designed to comply to the DDC Standard proposed by VESA (Figure 3-3) with the exception that it is not Access.bus™ capable. It operates in two modes, the Transmit-Only mode (1 Kbit) and the Bidirectional mode (2 Kbit). There is a separate 2-wire protocol to support each mode, each having a separate clock input but sharing a common data line (SDA). The device enters the Transmit-Only mode upon power-up. In this mode, the device transmits data bits on the SDA pin in response to a clock signal on the VCLK pin. The device will remain in this mode until a valid high-to-low transition is placed on the SCL input. When a valid transition on SCL is recognized, the device will switch into the Bidirectional mode and look for its control byte to be sent by the master. If it detects its control byte, it will stay in the Bidirectional mode. Otherwise, it will revert to the Transmit-Only mode after it sees 128 VCLK pulses. 2.1 2.2 After VCC has stabilized, the device will be in the Transmit-Only mode. Nine clock cycles on the VCLK pin must be given to the device for it to perform internal sychronization. During this period, the SDA pin will be in a high-impedance state. On the rising edge of the tenth clock cycle, the device will output the first valid data bit which will be the Most Significant bit in address 00h. (Figure 2-2). Transmit-Only Mode The device will power up in the Transmit-Only mode at address 00h. This mode supports a unidirectional 2-wire protocol for continuous transmission of the first 1 Kbit of the memory array. This device requires that it FIGURE 2-1: Initialization Procedure TRANSMIT-ONLY MODE SCL TVAA TVAA SDA Null Bit Bit 1 (LSB) Bit 1 (MSB) Bit 7 VCLK TVHIGH TVLOW FIGURE 2-2: DEVICE INITIALIZATION VCC SCL SDA TVAA High-impedance for 9 clock cycles TVAA Bit 8 Bit 7 TVPU VCLK DS21682E-page 4 1 2 8 9 10 11 © 2009 Microchip Technology Inc. 24LCS22A 3.0 BIDIRECTIONAL MODE Once the device has switched into the Bidirectional mode, the VCLK input is disregarded, with the exception that a logic high level is required to enable write capability. In Bidirectional mode the user has access to the entire 2K array, whereas in the TransmitOnly mode, the user can only access the first 1K. This mode supports a two-wire bidirectional data transmission protocol (I2C). In this protocol, a device that sends data on the bus is defined to be the transmitter, and a device that receives data from the bus is defined to be the receiver. The bus must be controlled by a master device that generates the Bidirectional mode clock (SCL), controls access to the bus and generates the Start and Stop conditions, while the 24LCS22A acts as the slave. Both master and slave can operate as transmitter or receiver, but the master device determines which mode is activated. In the Bidirectional mode, the 24LCS22A only responds to commands for device ‘1010 000X’. Before the 24LCS22A can be switched into the Bidirectional mode (Figure 3-1), it must enter the Transition mode, which is done by applying a valid high-to-low transition on the Bidirectional mode clock (SCL). As soon as it enters the Transition mode, it looks for a control byte ‘1010 000X’ on the I2C™ bus, and starts to count pulses on VCLK. Any high-to-low transition on the SCL line will reset the count. If it sees a pulse count of 128 on VCLK while the SCL line is idle, it will revert back to the Transmit-Only mode, and transmit its contents starting with the Most Significant bit in address 00h. However, if it detects the control byte on the I2C bus (Figure 3-2), it will switch to the Bidirectional mode. Once the device has made the transition to the Bidirectional mode, the only way to switch the device back to the Transmit-Only mode is to remove power from the device. The mode transition process is shown in detail in Figure 3-3. FIGURE 3-1: MODE MODE TRANSITION WITH RECOVERY TO TRANSMIT-ONLY MODE Transmit-Only Recovery to Transmit-Only mode Bidirectional TVHZ SCL (MSB of data in 00h) Bit8 SDA VCLK count = VCLK FIGURE 3-2: 1 2 3 4 127 128 SUCCESSFUL MODE TRANSITION TO BIDIRECTIONAL MODE Transmit-Only MODE Transition mode with possibility to return to Transmit-Only mode Bidirectional permanently SCL SDA VCLK count = VCLK 1 2 n S 0 1 0 1 0 0 0 0 0 ACK n < 128 © 2009 Microchip Technology Inc. DS21682E-page 5 24LCS22A DISPLAY OPERATION PER DDC STANDARD PROPOSED BY VESA® FIGURE 3-3: Display Power-on or DDC Circuit Powered from +5 volts Communication is idle Is Vsync present? No Yes High-to-low transition on SCL? Send EDID™ continuously using Vsync as clock No Yes High-to-low transition on SCL? No Yes Stop sending EDID. Switch to DDC2™ mode. Display has optional transition state ? DDC2 communication idle. Display waiting for address byte. No DDC2B address received? Yes Receive DDC2B command Yes Set Vsync counter = 0 or start timer Reset counter or timer Respond to DDC2B command Change on SCL, SDA or VCLK lines? No Is display Access.bus™ capable? Yes No High-low transition on SCL ? Reset Vsync counter = 0 Valid DDC2 address received? No VCLK cycle? No Yes Valid Access.bus address? Yes No No Yes No Yes See Access.bus specification to determine correct procedure. Yes Increment VCLK counter (if appropriate) No Counter=128 or timer expired? The 24LCS22A was designed to comply to the portion of flowchart inside dash box Yes Switch back to DDC1™ mode. Note 1: The base flowchart is copyright © 1993, 1994, 1995 Video Electronic Standard Association (VESA) from VESA’s Display Data Channel (DDC) Standard Proposal ver. 2p rev. 0, used by permission of VESA. 2: The dash box and text “The 24LCS22A and... inside dash box.” are added by Microchip Technology Inc. 3: Vsync signal is normally used to derive a signal for VCLK pin on the 24LCS22A. DS21682E-page 6 © 2009 Microchip Technology Inc. 24LCS22A 3.1 Bidirectional Mode Bus Characteristics The following bus protocol has been defined: • Data transfer may be initiated only when the bus is not busy • During data transfer, the data line must remain stable whenever the clock line is high. Changes in the data line while the clock line is high will be interpreted as a Start or Stop condition Each data transfer is initiated with a Start condition and terminated with a Stop condition. The number of the data bytes transferred between the Start and Stop conditions is determined by the master device and is theoretically unlimited, although only the last eight will be stored when doing a write operation. When an overwrite does occur it will replace data in a first-in firstout (FIFO) fashion. Note: Accordingly, the following bus conditions have been defined (Figure 3-4). 3.1.1 BUS NOT BUSY (A) 3.1.5 Both data and clock lines remain high. 3.1.2 START DATA TRANSFER (B) A high-to-low transition of the SDA line while the clock (SCL) is high determines a Start condition. All commands must be preceded by a Start condition. 3.1.3 3.1.4 DATA VALID (D) The state of the data line represents valid data when, after a Start condition, the data line is stable for the duration of the high period of the clock signal. The data on the line must be changed during the low period of the clock signal. There is one clock pulse per bit of data. FIGURE 3-4: SCL (A) ACKNOWLEDGE Each receiving device, when addressed, is obliged to generate an acknowledge after the reception of each byte. The master device must generate an extra clock pulse which is associated with this Acknowledge bit. Note: STOP DATA TRANSFER (C) A low-to-high transition of the SDA line while the clock (SCL) is high determines a Stop condition. All operations must be ended with a Stop condition. Once switched into Bidirectional mode, the 24LCS22A will remain in that mode until power is removed. Removing power is the only way to reset the 24LCS22A into the Transmit-Only mode. The 24LCS22A does not generate any Acknowledge bits if an internal programming cycle is in progress. The device that acknowledges has to pull down the SDA line during the Acknowledge clock pulse in such a way that the SDA line is stable low during the high period of the acknowledge related clock pulse. Of course, setup and hold times must be taken into account. A master must signal an end of data to the slave by not generating an Acknowledge bit on the last byte that has been clocked out of the slave. In this case, the slave must leave the data line high to enable the master to generate the Stop condition. DATA TRANSFER SEQUENCE ON THE SERIAL BUS (B) (D) Start Condition Address or Acknowledge Valid (D) (C) (A) SDA © 2009 Microchip Technology Inc. Data Allowed to Change Stop Condition DS21682E-page 7 24LCS22A FIGURE 3-5: BUS TIMING START/STOP SCL VHYS THD:STA TSU:STO TSU:STA SDA Start FIGURE 3-6: Stop BUS TIMING DATA TF TR THIGH TLOW SCL TSU:STA THD:DAT TSU:DAT TSU:STO THD:STA SDA IN TSP TBUF TAA TAA SDA OUT 3.1.6 SLAVE ADDRESS FIGURE 3-7: After generating a Start condition, the bus master transmits the slave address consisting of a 7-bit device code (1010000) for the 24LCS22A. Start Read/Write The eighth bit of slave address determines whether the master device wants to read or write to the 24LCS22A (Figure 3-7). The 24LCS22A monitors the bus for its corresponding slave address continuously. It generates an Acknowledge bit if the slave address was true and it is not in a Programming mode. Operation Slave Address R/W Read Write 1010000 1010000 1 0 DS21682E-page 8 CONTROL BYTE ALLOCATION R/W Slave Address 1 0 1 0 0 0 A 0 © 2009 Microchip Technology Inc. 24LCS22A 4.0 WRITE OPERATION 4.1 Byte Write Following the Start signal from the master, the slave address (four bits), three zero bits (000) and the R/W bit which is a logic low are placed onto the bus by the master transmitter. This indicates to the addressed slave receiver that a byte with a word address will follow after it has generated an Acknowledge bit during the ninth clock cycle. Therefore, the next byte transmitted by the master is the word address and will be written into the Address Pointer of the 24LCS22A. After receiving another Acknowledge signal from the 24LCS22A the master device will transmit the data word to be written into the addressed memory location. The 24LCS22A acknowledges again and the master generates a Stop condition. This initiates the internal write cycle, and during this time the 24LCS22A will not generate Acknowledge signals (Figure 4-1). It is required that VCLK be held at a logic high level during command and data transfer in order to program the device. This applies to both byte write and page write operation. Note, however, that the VCLK is ignored during the self-timed program operation. Changing VCLK from high-to-low during the self-timed program operation will not halt programming of the device. © 2009 Microchip Technology Inc. 4.2 Page Write The write control byte, word address and the first data byte are transmitted to the 24LCS22A in the same way as in a byte write. But instead of generating a Stop condition the master transmits up to eight data bytes to the 24LCS22A which are temporarily stored in the onchip page buffer and will be written into the memory after the master has transmitted a Stop condition. After the receipt of each word, the three lower order Address Pointer bits are internally incremented by one. The higher order five bits of the word address remains constant. If the master should transmit more than eight words prior to generating the Stop condition, the address counter will roll over and the previously received data will be overwritten. As with the byte write operation, once the Stop condition is received an internal write cycle will begin (Figure 5-2). It is required that VCLK be held at a logic high level during command and data transfer in order to program the device. This applies to both byte write and page write operation. Note, however, that the VCLK is ignored during the self-timed program operation. Changing VCLK from high-to-low during the self-timed program operation will not halt programming of the device. Note: Page write operations are limited to writing bytes within a single physical page, regardless of the number of bytes actually being written. Physical page boundaries start at addresses that are integer multiples of the page buffer size (or ‘page size’) and end at addresses that are integer multiples of [page size – 1]. If a Page Write command attempts to write across a physical page boundary, the result is that the data wraps around to the beginning of the current page (overwriting data previously stored there), instead of being written to the next page as might be expected. It is therefore necessary for the application software to prevent page write operations that would attempt to cross a page boundary. DS21682E-page 9 24LCS22A FIGURE 4-1: BYTE WRITE Bus Activity Master SDA Line S T A R T Word Address Control Byte S T O P Data S P A C K Bus Activity A C K A C K VCLK FIGURE 4-2: VCLK WRITE ENABLE TIMING SCL THD:STA SDA IN TSU:STO VCLK TVHST DS21682E-page 10 TSPVL © 2009 Microchip Technology Inc. 24LCS22A 5.0 ACKNOWLEDGE POLLING FIGURE 5-1: Since the device will not acknowledge during a write cycle, this can be used to determine when the cycle is complete (this feature can be used to maximize bus throughput). Once the Stop condition for a Write command has been issued from the master, the device initiates the internally timed write cycle. ACK polling can be initiated immediately. This involves the master sending a Start condition followed by the control byte for a Write command (R/W = 0). If the device is still busy with the write cycle, then no ACK will be returned. If the cycle is complete, then the device will return the ACK and the master can then proceed with the next Read or Write command. See Figure 5-1 for the flow diagram. ACKNOWLEDGE POLLING FLOW Send Write Command Send Stop Condition to Initiate Write Cycle Send Start Send Control Byte with R/W = 0 Did Device Acknowledge (ACK = 0)? No Yes Next Operation FIGURE 5-2: PAGE WRITE Bus Activity Master S T A R T SDA Line S Word Address Control Byte Bus Activity Data (n) S T O P Data n + 7 Data n + 1 P A C K A C K A C K A C K A C K VCLK © 2009 Microchip Technology Inc. DS21682E-page 11 24LCS22A 6.0 WRITE PROTECTION 7.0 When using the 24LCS22A in the Bidirectional mode, the VCLK pin can be used as a write-protect control pin. Setting VCLK high allows normal write operations, while setting VCLK low prevents writing to any location in the array. Connecting the VCLK pin to VSS would allow the 24LCS22A to operate as a serial ROM, although this configuration would prevent using the device in the Transmit-Only mode. Additionally, pin 3 performs a flexible write-protect function. The 24LCS22A contains a write protection control fuse whose factory default state is cleared. Writing any data to address 7Fh (normally the checksum in DDC applications) sets the fuse which enables the WP pin. Until this fuse is set, the 24LCS22A is always write enabled (if VCLK = 1). After the fuse is set, the write capability of the 24LCS22A is determined by both VCLK and WP pins (Table 6-1). TABLE 6-1: WRITE-PROTECT TRUTH TABLE VCLK WP Address 7Fh Written Mode for 00h-7Fh 0 1 1 1 X X 1/open 0 X No X Yes Read-only R/W R/W Read-only READ OPERATION Read operations are initiated in the same way as write operations with the exception that the R/W bit of the slave address is set to one. There are three basic types of read operations: current address read, random read and sequential read. 7.1 Current Address Read The 24LCS22A contains an address counter that maintains the address of the last word accessed, internally incremented by one. Therefore, if the previous access (either a read or write operation) was to address n, the next current address read operation would access data from address n + 1. Upon receipt of the slave address with R/W bit set to one, the 24LCS22A issues an acknowledge and transmits the eight bit data word. The master will not acknowledge the transfer, but does generate a Stop condition and the 24LCS22A discontinues transmission (Figure 7-1). FIGURE 7-1: Bus Activity Master SDA Line CURRENT ADDRESS READ S T A R T Control Byte Data n S10100001 P A C K Bus Activity 7.2 S T O P N O A C K Random Read Random read operations allow the master to access any memory location in a random manner. To perform this type of read operation, first the word address must be set. This is done by sending the word address to the 24LCS22A as part of a write operation. After the word address is sent, the master generates a Start condition following the acknowledge. This terminates the write operation, but not before the internal Address Pointer is set. Then the master issues the control byte again but with the R/W bit set to a one. The 24LCS22A will then issue an acknowledge and transmits the 8-bit data word. The master will not acknowledge the transfer, but does generate a Stop condition and the 24LCS22A discontinues transmission (Figure 7-2). DS21682E-page 12 © 2009 Microchip Technology Inc. 24LCS22A FIGURE 7-2: RANDOM READ S T A R T Bus Activity Master Control Byte S T A R T Word Address S 1 0 1 0 0 0 0 0 SDA Line FIGURE 7-3: S T O P Data n S 1 0 1 0 0 0 0 1 A C K Bus Activity Control Byte A C K P A C K N O A C K SEQUENTIAL READ Bus Activity Master Data n Control Byte Data n + 2 Data n + 1 S T O P Data n + x P SDA Line Bus Activity 7.3 A C K A C K Sequential Read Sequential reads are initiated in the same way as a random read except that after the 24LCS22A transmits the first data byte, the master issues an acknowledge as opposed to a Stop condition in a random read. This directs the 24LCS22A to transmit the next sequentially addressed 8-bit word (Figure 7-3). A C K A C K N O A C K 7.4 Noise Protection The 24LCS22A employs a VCC threshold detector circuit which disables the internal erase/write logic if the VCC is below 1.5 volts at nominal conditions. The SDA, SCL and VCLK inputs have Schmitt Trigger and filter circuits which suppress noise spikes to assure proper device operation even on a noisy bus. To provide sequential reads the 24LCS22A contains an internal Address Pointer which is incremented by one at the completion of each operation. This Address Pointer allows the entire memory contents to be serially read during one operation. © 2009 Microchip Technology Inc. DS21682E-page 13 24LCS22A 8.0 PIN DESCRIPTIONS The descriptions of the pins are listed in Table 8-1. TABLE 8-1: PIN FUNCTION TABLE Name WP Write-Protect (active low) VSS Ground SDA Serial Address/Data I/O SCL Serial Clock (Bidirectional mode) VCLK 8.1 Function Serial Clock (Transmit-Only mode) VCC +2.5V to 5.5V Power Supply NC No Internal Connection 8.3 Serial Clock (SCL) This pin is the clock input for the Bidirectional mode, and is used to synchronize data transfer to and from the device. It is also used as the signaling input to switch the device from the Transmit-Only mode to the Bidirectional mode. It must remain high for the chip to continue operation in the Transmit-Only mode. 8.4 Serial Clock (VCLK) This pin is the clock input for the Transmit-Only mode (DDC1). In the Transmit-Only mode, each bit is clocked out on the rising edge of this signal. In the Bidirectional mode, a high logic level is required on this pin to enable write capability. Write-Protect (WP) This pin is used for flexible write protection of the 24LCS22A. When memory location 7Fh is written with any data, this pin is enabled and determines the write capability of the 24LCS22A (Table 6-1). 8.2 Serial Address/Data Input/Output (SDA) This pin is used to transfer addresses and data into and out of the device, when the device is in the Bidirectional mode. In the Transmit-Only mode, which only allows data to be read from the device, data is also transferred on the SDA pin. This pin is an open drain terminal, therefore the SDA bus requires a pull-up resistor to VCC (typical 10 kΩ for 100 kHz, 2 kΩ for 400 kHz). For normal data transfer in the Bidirectional mode, SDA is allowed to change only during SCL low. Changes during SCL high are reserved for indicating the Start and Stop conditions. DS21682E-page 14 © 2009 Microchip Technology Inc. 24LCS22A 9.0 PACKAGING INFORMATION 9.1 Package Marking Information 8-Lead PDIP (300 mil) XXXXXXXX TXX e3 NNN YYWW 8-Lead SOIC (3.90 mm) XXXXXXXT XX e3 YYWW NNN Legend: XX...X T Y YY WW NNN e3 * Example: 24LCS22A I/P e3 NNN 0145 Example: 4LCS22AI SN e3 0145 NNN Part number or part number code Temperature (I, E) Year code (last digit of calendar year) Year code (last 2 digits of calendar year) Week code (week of January 1 is week ‘01’) Alphanumeric traceability code (2 characters for small packages) Pb-free JEDEC designator for Matte Tin (Sn) Note: For very small packages with no room for the Pb-free JEDEC designator e3 , the marking will only appear on the outer carton or reel label. Note: In the event the full Microchip part number cannot be marked on one line, it will be carried over to the next line, thus limiting the number of available characters for customer-specific information. Standard marking consists of Microchip part number, year code, week code, traceability code (facility code, mask rev#, and assembly code). © 2009 Microchip Technology Inc. DS21682E-page 15 24LCS22A 3 &' !&"&4#*!(!!& 4%& &#& &&255***' '54 N NOTE 1 E1 1 3 2 D E A2 A L A1 c e eB b1 b 6&! '! 9'&! 7"') %! 7,8. 7 7 7: ; < & & & = = ##44!! - 1!& & = = "#& "#>#& . - - ##4>#& . < : 9& -< -? & & 9 - 9#4!! < ) ? ) < 1 = = 69#>#& 9 *9#>#& : *+ 1, - !"#$%&"' ()"&'"!&) &#*&&&# +%&,&!& - '! !#.# &"#' #%! &"! ! #%! &"! !! &$#/!# '! #& .0 1,21!'! &$& "! **& "&& ! * ,<1 DS21682E-page 16 © 2009 Microchip Technology Inc. 24LCS22A ! ""#$%& !' 3 &' !&"&4#*!(!!& 4%& &#& &&255***' '54 D e N E E1 NOTE 1 1 2 3 α h b h A2 A c φ L A1 L1 6&! '! 9'&! 7"') %! β 99.. 7 7 7: ; < & : 8& = 1, = ##44!! = = &# %%+ = : >#& . ##4>#& . -1, : 9& 1, ?1, ,'%@ & A = 3 &9& 9 = 3 && 9 .3 3 & I B = <B 9#4!! = 9#>#& ) - = #%& D B = B #%&1 && ' E B = B !"#$%&"' ()"&'"!&) &#*&&&# +%&,&!& - '! !#.# &"#' #%! &"! ! #%! &"! !! &$#''!# '! #& .0 1,2 1!'! &$& "! **& "&& ! .32 %'! ("!"*& "&& (% % '& " !! * ,1 © 2009 Microchip Technology Inc. DS21682E-page 17 24LCS22A ! ""#$%& !' 3 &' !&"&4#*!(!!& 4%& &#& &&255***' '54 DS21682E-page 18 © 2009 Microchip Technology Inc. 24LCS22A APPENDIX A: REVISION HISTORY Revision B Corrections to Section 1.0, Electrical Characteristics. Revision C Revised Section 8.1. Added new package legend. Revision D (07/2008) Revised Features (added Pb-free); Replaced Package Drawings (Rev. AP); Revised Product ID System. Revision E (06/2009) Revised Package Marking examples. © 2009 Microchip Technology Inc. DS21682E-page 19 24LCS22A NOTES: DS21682E-page 20 © 2009 Microchip Technology Inc. 24LCS22A THE MICROCHIP WEB SITE CUSTOMER SUPPORT Microchip provides online support via our WWW site at www.microchip.com. This web site is used as a means to make files and information easily available to customers. Accessible by using your favorite Internet browser, the web site contains the following information: Users of Microchip products can receive assistance through several channels: • Product Support – Data sheets and errata, application notes and sample programs, design resources, user’s guides and hardware support documents, latest software releases and archived software • General Technical Support – Frequently Asked Questions (FAQ), technical support requests, online discussion groups, Microchip consultant program member listing • Business of Microchip – Product selector and ordering guides, latest Microchip press releases, listing of seminars and events, listings of Microchip sales offices, distributors and factory representatives • • • • • Distributor or Representative Local Sales Office Field Application Engineer (FAE) Technical Support Development Systems Information Line Customers should contact their distributor, representative or field application engineer (FAE) for support. Local sales offices are also available to help customers. A listing of sales offices and locations is included in the back of this document. Technical support is available through the web site at: http://support.microchip.com CUSTOMER CHANGE NOTIFICATION SERVICE Microchip’s customer notification service helps keep customers current on Microchip products. Subscribers will receive e-mail notification whenever there are changes, updates, revisions or errata related to a specified product family or development tool of interest. To register, access the Microchip web site at www.microchip.com, click on Customer Change Notification and follow the registration instructions. © 2009 Microchip Technology Inc. DS21682E-page 21 24LCS22A READER RESPONSE It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip product. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation can better serve you, please FAX your comments to the Technical Publications Manager at (480) 792-4150. Please list the following information, and use this outline to provide us with your comments about this document. To: Technical Publications Manager RE: Reader Response Total Pages Sent ________ From: Name Company Address City / State / ZIP / Country Telephone: (_______) _________ - _________ FAX: (______) _________ - _________ Application (optional): Would you like a reply? Device: 24LCS22A Y N Literature Number: DS21682E Questions: 1. What are the best features of this document? 2. How does this document meet your hardware and software development needs? 3. Do you find the organization of this document easy to follow? If not, why? 4. What additions to the document do you think would enhance the structure and subject? 5. What deletions from the document could be made without affecting the overall usefulness? 6. Is there any incorrect or misleading information (what and where)? 7. How would you improve this document? DS21682E-page 22 © 2009 Microchip Technology Inc. 24LCS22A PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. PART NO. Device X /XX Temperature Range Package Examples: a) b) Device: 24LCS22A: 2K VESA E-EDID Serial EEPROM 24LCS22AT: 2K VESA E-EDID Serial EEPROM (Tape and Reel) Temperature Range: I Package: P = Plastic DIP (300 mil Body), 8-Lead SN = Plastic SOIC (3.90 mm Body), 8-Lead c) 24LCS22A-I/P: Industrial temperature, PDIP package. 24LCS22A-I/SN: Industrial temperature, SOIC package. 24LCS22AT-I/SN:Tape and Reel, Industrial temperature, SOIC package. = -40°C to +85°C © 2009 Microchip Technology Inc. DS21682E-page 23 24LCS22A NOTES: DS21682E-page 24 © 2009 Microchip Technology Inc. Note the following details of the code protection feature on Microchip devices: • Microchip products meet the specification contained in their particular Microchip Data Sheet. • Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. • There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property. • Microchip is willing to work with the customer who is concerned about the integrity of their code. • Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as “unbreakable.” Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act. Information contained in this publication regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer’s risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights. Trademarks The Microchip name and logo, the Microchip logo, dsPIC, KEELOQ, KEELOQ logo, MPLAB, PIC, PICmicro, PICSTART, rfPIC and UNI/O are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. FilterLab, Hampshire, HI-TECH C, Linear Active Thermistor, MXDEV, MXLAB, SEEVAL and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A. Analog-for-the-Digital Age, Application Maestro, CodeGuard, dsPICDEM, dsPICDEM.net, dsPICworks, dsSPEAK, ECAN, ECONOMONITOR, FanSense, HI-TIDE, In-Circuit Serial Programming, ICSP, ICEPIC, Mindi, MiWi, MPASM, MPLAB Certified logo, MPLIB, MPLINK, mTouch, nanoWatt XLP, Omniscient Code Generation, PICC, PICC-18, PICkit, PICDEM, PICDEM.net, PICtail, PIC32 logo, REAL ICE, rfLAB, Select Mode, Total Endurance, TSHARC, WiperLock and ZENA are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. © 2009, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper. Microchip received ISO/TS-16949:2002 certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona; Gresham, Oregon and design centers in California and India. The Company’s quality system processes and procedures are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping devices, Serial EEPROMs, microperipherals, nonvolatile memory and analog products. In addition, Microchip’s quality system for the design and manufacture of development systems is ISO 9001:2000 certified. © 2009 Microchip Technology Inc. DS21682E-page 25 WORLDWIDE SALES AND SERVICE AMERICAS ASIA/PACIFIC ASIA/PACIFIC EUROPE Corporate Office 2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7200 Fax: 480-792-7277 Technical Support: http://support.microchip.com Web Address: www.microchip.com Asia Pacific Office Suites 3707-14, 37th Floor Tower 6, The Gateway Harbour City, Kowloon Hong Kong Tel: 852-2401-1200 Fax: 852-2401-3431 India - Bangalore Tel: 91-80-3090-4444 Fax: 91-80-3090-4080 India - New Delhi Tel: 91-11-4160-8631 Fax: 91-11-4160-8632 Austria - Wels Tel: 43-7242-2244-39 Fax: 43-7242-2244-393 Denmark - Copenhagen Tel: 45-4450-2828 Fax: 45-4485-2829 India - Pune Tel: 91-20-2566-1512 Fax: 91-20-2566-1513 France - Paris Tel: 33-1-69-53-63-20 Fax: 33-1-69-30-90-79 Japan - Yokohama Tel: 81-45-471- 6166 Fax: 81-45-471-6122 Germany - Munich Tel: 49-89-627-144-0 Fax: 49-89-627-144-44 Atlanta Duluth, GA Tel: 678-957-9614 Fax: 678-957-1455 Boston Westborough, MA Tel: 774-760-0087 Fax: 774-760-0088 Chicago Itasca, IL Tel: 630-285-0071 Fax: 630-285-0075 Cleveland Independence, OH Tel: 216-447-0464 Fax: 216-447-0643 Dallas Addison, TX Tel: 972-818-7423 Fax: 972-818-2924 Detroit Farmington Hills, MI Tel: 248-538-2250 Fax: 248-538-2260 Kokomo Kokomo, IN Tel: 765-864-8360 Fax: 765-864-8387 Los Angeles Mission Viejo, CA Tel: 949-462-9523 Fax: 949-462-9608 Santa Clara Santa Clara, CA Tel: 408-961-6444 Fax: 408-961-6445 Toronto Mississauga, Ontario, Canada Tel: 905-673-0699 Fax: 905-673-6509 Australia - Sydney Tel: 61-2-9868-6733 Fax: 61-2-9868-6755 China - Beijing Tel: 86-10-8528-2100 Fax: 86-10-8528-2104 China - Chengdu Tel: 86-28-8665-5511 Fax: 86-28-8665-7889 Korea - Daegu Tel: 82-53-744-4301 Fax: 82-53-744-4302 China - Hong Kong SAR Tel: 852-2401-1200 Fax: 852-2401-3431 Korea - Seoul Tel: 82-2-554-7200 Fax: 82-2-558-5932 or 82-2-558-5934 China - Nanjing Tel: 86-25-8473-2460 Fax: 86-25-8473-2470 Malaysia - Kuala Lumpur Tel: 60-3-6201-9857 Fax: 60-3-6201-9859 China - Qingdao Tel: 86-532-8502-7355 Fax: 86-532-8502-7205 Malaysia - Penang Tel: 60-4-227-8870 Fax: 60-4-227-4068 China - Shanghai Tel: 86-21-5407-5533 Fax: 86-21-5407-5066 Philippines - Manila Tel: 63-2-634-9065 Fax: 63-2-634-9069 China - Shenyang Tel: 86-24-2334-2829 Fax: 86-24-2334-2393 Singapore Tel: 65-6334-8870 Fax: 65-6334-8850 China - Shenzhen Tel: 86-755-8203-2660 Fax: 86-755-8203-1760 Taiwan - Hsin Chu Tel: 886-3-6578-300 Fax: 886-3-6578-370 China - Wuhan Tel: 86-27-5980-5300 Fax: 86-27-5980-5118 Taiwan - Kaohsiung Tel: 886-7-536-4818 Fax: 886-7-536-4803 China - Xiamen Tel: 86-592-2388138 Fax: 86-592-2388130 Taiwan - Taipei Tel: 886-2-2500-6610 Fax: 886-2-2508-0102 China - Xian Tel: 86-29-8833-7252 Fax: 86-29-8833-7256 Thailand - Bangkok Tel: 66-2-694-1351 Fax: 66-2-694-1350 Italy - Milan Tel: 39-0331-742611 Fax: 39-0331-466781 Netherlands - Drunen Tel: 31-416-690399 Fax: 31-416-690340 Spain - Madrid Tel: 34-91-708-08-90 Fax: 34-91-708-08-91 UK - Wokingham Tel: 44-118-921-5869 Fax: 44-118-921-5820 China - Zhuhai Tel: 86-756-3210040 Fax: 86-756-3210049 03/26/09 DS21682E-page 26 © 2009 Microchip Technology Inc.