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Features

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Fast Read Access Time - 100 ns 5-Volt-Only Reprogramming Sector Program Operation Single Cycle Reprogram (Erase and Program) 2048 Sectors (256 bytes/sector) Internal Address and Data Latches for 256-Bytes Internal Program Control and Timer Hardware and Software Data Protection Two 16 KB Boot Blocks with Lockout Fast Sector Program Cycle Time - 10 ms DATA Polling for End of Program Detection Low Power Dissipation 40 mA Active Current 100 µA CMOS Standby Current Typical Endurance > 10,000 Cycles Single 5V ± 10% Supply CMOS and TTL Compatible Inputs and Outputs

Description
The AT29C040A is a 5-volt-only in-system Flash Programmable and Erasable Read Only Memory (PEROM). Its 4 megabits of memory is organized as 524,288 words by 8 bits. Manufactured with Atmel's advanced nonvolatile CMOS EEPROM technology, the device offers access times up to 100 ns, and a low 220 mW power dissipation. When the device is deselected, the CMOS standby current is less than 100 µA. The device endurance is such that any sector can typically be written to in excess of 10,000 times. The programming algorithm is compatible with other devices in Atmel's 5-volt-only Flash family. (continued)

4-Megabit (512K x 8) 5-volt Only 256-Byte Sector CMOS Flash Memory AT29C040A

AT29C040A

Pin Configurations
Pin Name A0 - A18 CE OE WE Function Addresses Chip Enable Output Enable Write Enable

I/O0 - I/O7 Data Inputs/Outputs NC No Connect

DIP Top View

TSOP Top View

Type 1

0333E­9/97

Description (Continued)
To allow for simple in-system reprogrammability, the AT29C040A does not require high input voltages for programming. Five-volt-only commands determine the operation of the device. Reading data out of the device is similar to reading from an EPROM. Reprogramming the AT29C040A is performed on a sector basis; 256-bytes of data are loaded into the device and then simultaneously programmed. During a reprogram cycle, the address locations and 256bytes of data are internally latched, freeing the address and data bus for other operations. Following the initiation of a program cycle, the device will automatically erase the sector and then program the latched data using an internal control timer. The end of a program cycle can be detected by DATA polling of I/O7. Once the end of a program cycle has been detected, a new access for a read or program can begin.

Block Diagram

Device Operation
READ: The AT29C040A is accessed like an EPROM. When CE and OE are low and WE is high, the data stored at the memory location determined by the address pins is asserted on the outputs. The outputs are put in the high impedance state whenever CE or OE is high. This dualline control gives designers flexibility in preventing bus contention. BYTE LOAD: Byte loads are used to enter the 256bytes of a sector to be programmed or the software codes for data protection. A byte load is performed by applying a low pulse on the WE or CE input with CE or WE low (respectively) and OE high. The address is latched on the falling edge of CE or WE, whichever occurs last. The data is latched by the first rising edge of CE or WE. PROGRAM: The device is reprogrammed on a sector basis. If a byte of data within a sector is to be changed, data for the entire sector must be loaded into the device. Any byte that is not loaded during the programming of its sector will be erased to read FFH. Once the bytes of a sector are loaded into the device, they are simultaneously programmed during the internal programming period. After the first data byte has been loaded into the device, successive bytes are entered in the same manner. Each new byte to be programmed must have its high to low transition on WE (or CE) within 150 µs of the low to high transition of WE (or CE) of the preceding byte. If a high to low transition is not detected within 150 µs of the last low to high transition, the load period will end and the internal programming period will start. A8 to A18 specify the sector address. The sector address must be valid during each high to low tran2 sition of WE (or CE). A0 to A7 specify the byte address within the sector. The bytes may be loaded in any order; sequential loading is not required. Once a programming operation has been initiated, and for the duration of tWC, a read operation will effectively be a polling operation. SOFTWARE DATA PROTECTION: A software controlled data protection feature is available on the AT29C040A. Once the software protection is enabled a software algorithm must be issued to the device before a program may be performed. The software protection feature may be enabled or disabled by the user; when shipped from Atmel, the software data protection feature is disabled. To enable the software data protection, a series of three program commands to specific addresses with specific data must be performed. After the software data protection is enabled the same three program commands must begin each program cycle in order for the programs to occur. All software program commands must obey the sector program timing specifications. The SDP feature protects all sectors, not just a single sector. Once set, the software data protection feature remains active unless its disable command is issued. Power transitions will not reset the software data protection feature, however the software feature will guard against inadvertent program cycles during power transitions. After setting SDP, any attempt to write to the device without the three-byte command sequence will start the internal write timers. No data will be written to the device; however, for the duration of t WC, a read operation will effectively be a polling operation. (continued)

AT29C040A

AT29C040A
Device Operation (Continued)
After the software data protection's 3-byte command code is given, a byte load is performed by applying a low pulse on the WE or CE input with CE or WE low (respectively) and OE high. The address is latched on the falling edge of CE or WE, whichever occurs last. The data is latched by the first rising edge of CE or WE. The 256-bytes of data must be loaded into each sector by the same procedure as outlined in the program section under device operation. HARDWARE DATA PROTECTION: Hardware features protect against inadvertent programs to the AT29C040A in the following ways: (a) VCC sense-- if VCC is below 3.8V (typical), the program function is inhibited. (b) VCC power on delay-- once VCC has reached the VCC sense level, the device will automatically time out 5 ms (typical) before programming. (c) Program inhibit-- holding any one of OE low, CE high or WE high inhibits program cycles. (d) Noise filter-- pulses of less than 15 ns (typical) on the WE or CE inputs will not initiate a program cycle. PRODUCT IDENTIFICATION: The product identification mode identifies the device and manufacturer as Atmel. It may be accessed by hardware or software operation. The hardware operation mode can be used by an external programmer to identify the correct programming algorithm for the Atmel product. In addition, users may wish to use the software product identification mode to identify the part (i.e. using the device code), and have the system software use the appropriate sector size for program operations. In this manner, the user can have a common board design for 256K to 4-megabit densities and, with each density's sector size in a memory map, have the system software apply the appropriate sector size. For details, see Operating Modes (for hardware operation) or Software Product Identification. The manufacturer and device code is the same for both modes. DATA POLLING: The AT29C040A features DATA polling to indicate the end of a program cycle. During a program cycle an attempted read of the last byte loaded will result in the complement of the loaded data on I/O7. Once the program cycle has been completed, true data is valid on all outputs and the next cycle may begin. DATA polling may begin at any time during the program cycle. TOGGLE BIT: I n a d d i t i o n t o DATA p o l l i n g t h e AT29C040A provides another method for determining the end of a program or erase cycle. During a program or erase operation, successive attempts to read data from the device will result in I/O6 toggling between one and zero. Once the program cycle has completed, I/O6 will stop toggling and valid data will be read. Examining the toggle bit may begin at any time during a program cycle. OPTIONAL CHIP ERASE MODE: The entire device can be erased by using a 6-byte software code. Please see Software Chip Erase application note for details. BOOT BLOCK PROGRAMMING LOCKOUT: The AT29C040A has two designated memory blocks that have a programming lockout feature. This feature prevents programming of data in the designated block once the feature has been enabled. Each of these blocks consists of 16K bytes; the programming lockout feature can be set independently for either block. While the lockout feature does not have to be activated, it can be activated for either or both blocks. These two 16K memory sections are referred to as boot blocks. Secure code which will bring up a system can be contained in a boot block. The AT29C040A blocks are located in the first 16K bytes of memory and the last 16K bytes of memory. The boot block programming lockout feature can therefore support systems that boot from the lower addresses of memory or the higher addresses. Once the programming lockout feature has been activated, the data in that block can no longer be erased or programmed; data in other memory locations can still be changed through the regular programming methods. To activate the lockout feature, a series of seven program commands to specific addresses with specific data must be performed. Please see Boot Block Lockout Feature Enable Algorithm. If the boot block lockout feature has been activated on either block, the chip erase function will be disabled.

Absolute Maximum Ratings*
Temperature Under Bias................. -55°C to +125°C Storage Temperature...................... -65°C to +150°C All Input Voltages (including NC Pins) with Respect to Ground ................... -0.6V to +6.25V All Output Voltages with Respect to Ground .............-0.6V to V CC + 0.6V Voltage on OE with Respect to Ground ................... -0.6V to +13.5V

(continued)

*NOTICE: Stresses beyond 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 these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

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Device Operation (Continued)
BOOT BLOCK LOCKOUT DETECTION: A software method is available to determine whether programming of either boot block section is locked out. See Software Product Identification Entry and Exit sections. When the device is in the software product identification mode, a read from location 00002H will show if programming the lower address boot block is locked out while reading location FFFF2H will do so for the upper boot block. If the data is FE, the corresponding block can be programmed; if the data is FF, the program lockout feature has been activated and the corresponding block cannot be programmed. The software product identification exit mode should be used to return to standard operation.

DC and AC Operating Range
AT29C040A-10 Operating Temperature (Case) VCC Power Supply Com. Ind. 0°C - 70°C -40°C - 85°C 5V ± 10% AT29C040A-12 0°C - 70°C -40°C - 85°C 5V ± 10% AT29C040A-15 0°C - 70°C -40°C - 85°C 5V ± 10%

Operating Modes
Mode Read Program (2) Standby/Write Inhibit Program Inhibit Program Inhibit Output Disable Product Identification Hardware Software (5)
Notes: 1. X can be VIL or VIH. 2. Refer to AC Programming Waveforms. 3. VH = 12.0V ± 0.5V.

CE VIL VIL VIH X X X

OE VIL VIH X
(1)

WE VIH VIL X VIH X X

Ai Ai Ai X

I/O DOUT DIN High Z

X VIL VIH

High Z
A1 - A18 = VIL, A9 = VH, (3) A0 = VIL A1 - A18 = VIL, A9 = VH, (3) A0 = VIH A0 = VIL A0 = VIH

Manufacturer Code (4) Device Code (4) Manufacturer Code (4) Device Code (4)

VIL

VIL

VIH

4. Manufacturer Code: 1F, Device Code: A4 5. See details under Software Product Identification Entry/Exit.

DC Characteristics
Symbol ILI ILO ISB1 ISB2 ICC VIL VIH VOL VOH1 VOH2 4 Parameter Input Load Current Output Leakage Current VCC Standby Current CMOS VCC Standby Current TTL VCC Active Current Input Low Voltage Input High Voltage Output Low Voltage Output High Voltage Output High Voltage CMOS IOL = 2.1 mA IOH = -400 µA IOH = -100 µA; VCC = 4.5V 2.4 4.2 2.0 .45 Condition VIN = 0V to VCC VI/O = 0V to VCC CE = VCC - 0.3V to VCC CE = 2.0V to VCC f = 5 MHz; IOUT = 0 mA Com. Ind. Min Max 10 10 100 300 3 40 0.8 Units µA µA µA µA mA mA V V V V V

AT29C040A

AT29C040A
AC Read Characteristics
AT29C040A-10 Symbol tACC tCE tOE tDF tOH
(1) (2) (3, 4)

AT29C040A-12
Min Max

AT29C040A-15
Min Max

Parameter Address to Output Delay CE to Output Delay OE to Output Delay CE or OE to Output Float Output Hold from OE, CE or Address, whichever occurred first

Min

Max

Units ns ns ns ns ns

100 100 0 0 0 40 25 0 0 0

120 120 50 30 0 0 0

150 150 70 40

AC Read Waveforms (1, 2, 3, 4)

Notes: 1. CE may be delayed up to tACC - tCE after the address transition without impact on tACC . 2. OE may be delayed up to tCE - tOE after the falling edge of CE without impact on tCE or by tACC - tOE after an address change without impact on tACC .

3. tDF is specified from OE or CE whichever occurs first (CL = 5 pF). 4. This parameter is characterized and is not 100% tested.

Input Test Waveforms and Measurement Level

Output Test Load

tR, tF < 5 ns

Pin Capacitance (f = 1 MHz, T = 25°C) (1)
Typ CIN COUT
Note:

Max 6 12

Units pF pF

Conditions VIN = 0V VOUT = 0V

4 8
1. This parameter is characterized and is not 100% tested.

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AC Byte Load Characteristics
Symbol tAS, tOES tAH tCS tCH tWP tDS tDH, tOEH tWPH Parameter Address, OE Set-up Time Address Hold Time Chip Select Set-up Time Chip Select Hold Time Write Pulse Width (WE or CE) Data Set-up Time Data, OE Hold Time Write Pulse Width High Min 10 50 0 0 90 50 10 100 Max Units ns ns ns ns ns ns ns ns

AC Byte Load Waveforms (1)
WE Controlled

CE Controlled

Note:

1. A complete sector (256-bytes) should be loaded using the waveforms shown in these byte load waveform diagrams.

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AT29C040A

AT29C040A
Program Cycle Characteristics
Symbol tWC tAS tAH tDS tDH tWP tBLC tWPH Parameter Write Cycle Time Address Set-up Time Address Hold Time Data Set-up Time Data Hold Time Write Pulse Width Byte Load Cycle Time Write Pulse Width High 100 10 50 50 10 90 150 Min Max 10 Units ms ns ns ns ns ns µs ns

Program Cycle Waveforms (1, 2, 3)

Notes: 1. A8 through A18 must specify the sector address during each high to low transition of WE (or CE). 2. OE must be high when WE and CE are both low.

3. All bytes that are not loaded within the sector being programmed will be indeterminate.

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Software Data (1) Protection Enable Algorithm
LOAD DATA AA TO ADDRESS 5555 LOAD DATA 55 TO ADDRESS 2AAA LOAD DATA A0 TO ADDRESS 5555 LOAD DATA TO (4) SECTOR (256 BYTES)

Software Data (1) Protection Disable Algorithm
LOAD DATA AA TO ADDRESS 5555 LOAD DATA 55 TO ADDRESS 2AAA LOAD DATA 80 TO ADDRESS 5555 LOAD DATA AA TO ADDRESS 5555 LOAD DATA 55 TO ADDRESS 2AAA LOAD DATA 20 TO ADDRESS 5555 LOAD DATA TO (4) SECTOR (256 BYTES)

WRITES ENABLED

ENTER DATA PROTECT STATE

(2)

Notes for software program code: 1. Data Format: I/O7 - I/O0 (Hex); Address Format: A14 - A0 (Hex). 2. Data Protect state will be activated at end of program cycle. 3. Data Protect state will be deactivated at end of program period. 4. 256-bytes of data MUST BE loaded.

EXIT DATA PROTECT STATE

(3)

Software Protected Program Cycle Waveform (1, 2, 3)

Notes: 1. A8 through A18 must specify the sector address during each high to low transition of WE (or CE) after the software code has been entered.

2. OE must be high when WE and CE are both low. 3. All bytes that are not loaded within the sector being programmed will be indeterminate.

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AT29C040A

AT29C040A
Data Polling Characteristics
Symbol tDH tOEH tOE tWR Parameter Data Hold Time OE Hold Time OE to Output Delay
(2) (1)

Min 10 10 0

Typ

Max

Units ns ns ns ns

Write Recovery Time

Notes: 1. These parameters are characterized and not 100% tested. 2. See tOE spec in AC Read Characteristics.

Data Polling Waveforms

Toggle Bit Characteristics
Symbol tDH tOEH tOE tOEHP tWR Parameter Data Hold Time OE Hold Time OE to Output Delay OE High Pulse Write Recovery Time

(1)

Min 10 10
(2)

Typ

Max

Units ns ns ns ns ns

150 0

Notes: 1. These parameters are characterized and not 100% tested. 2. See tOE spec in AC Read Characteristics.

Toggle Bit Waveforms (1, 2, 3)

Notes: 1. Toggling either OE or CE or both OE and CE will operate toggle bit. The tOEHP specification must be met by the toggling input(s).

2. Beginning and ending state of I/O6 will vary. 3. Any address location may be used but the address should not vary.

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Software Product (1) Identification Entry
LOAD DATA AA TO ADDRESS 5555 LOAD DATA 55 TO ADDRESS 2AAA LOAD DATA 90 TO ADDRESS 5555

Boot Block Lockout (1) Feature Enable Algorithm
LOAD DATA AA TO ADDRESS 5555 LOAD DATA 55 TO ADDRESS 2AAA LOAD DATA 80 TO ADDRESS 5555 LOAD DATA AA TO ADDRESS 5555 LOAD DATA 55 TO ADDRESS 2AAA LOAD DATA 40 TO ADDRESS 5555

PAUSE 10 mS

ENTER PRODUCT IDENTIFICATION (2, 3, 5) MODE

Software Product (1) Identification Exit
LOAD DATA AA TO ADDRESS 5555 LOAD DATA 55 TO ADDRESS 2AAA LOAD DATA F0 TO ADDRESS 5555

LOAD DATA 00 TO ADDRESS 00000H (2)

LOAD DATA FF TO ADDRESS FFFFFH (3)

PAUSE 10 mS

PAUSE 10 mS

PAUSE 10 mS

EXIT PRODUCT IDENTIFICATION (4) MODE

Notes for boot block lockout feature enable: 1. Data Format: I/O7 - I/O0 (Hex); Address Format: A14 - A0 (Hex). 2. Lockout feature set on lower address boot block. 3. Lockout feature set on higher address boot block.

Notes for software product identification: 1. Data Format: I/O7 - I/O0 (Hex); Address Format: A14 - A0 (Hex). 2. A1 - A18 = VIL. Manufacture Code is read for A0 = VIL; Device Code is read for A0 = VIH. 3. The device does not remain in identification mode if powered down. 4. The device returns to standard operation mode. 5. Manufacturer Code: 1F Device Code: A4

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AT29C040A

AT29C040A
Ordering Information
tACC (ns) 100 ICC (mA)
Active Standby

Ordering Code AT29C040A-10PC AT29C040A-10TC AT29C040A-10PI AT29C040A-10TI AT29C040A-12PC AT29C040A-12TC AT29C040A-12PI AT29C040A-12TI AT29C040A-15PC AT29C040A-15TC AT29C040A-15PI

Package 32P6 32T 32P6 32T 32P6 32T 32P6 32T 32P6 32P6

Operation Range Commercial (0° to 70°C) Industrial (-40° to 85°C) Commercial (0° to 70°C) Industrial (-40° to 85°C) Commercial (0° to 70°C) Industrial (-40° to 85°C)

40 40

0.1 0.3 0.1 0.3 0.1 0.3

120

40 40

150

40 40

Package Type
32P6 32T
32 Lead, 0.600" Wide, Plastic Dual Inline Package (PDIP) 32 Lead, Thin Small Outline Package (TSOP)

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