X28LC512/X28LC513
512K |
X28LC512/X28LC513 |
64K x 8 Bit |
3.3 Volt, Byte Alterable E2PROM
FEATURES
•Low VCC Operation: VCC = 3.3V ±10%
•Access Time: 150ns
•Simple Byte and Page Write —Self-Timed
—No Erase Before Write
—No Complex Programming Algorithms —No Overerase Problem
•Low Power CMOS:
—Active: 25mA —Standby: 150 μA
•Software Data Protection
—Protects Data Against System Level Inadvertant Writes
•High Speed Page Write Capability
•Highly Reliable Direct Write™ Cell —Endurance: 10,000 Write Cycles —Data Retention: 100 Years
•Early End of Write Detection
— DATA Polling
—Toggle Bit Polling
PIN CONFIGURATIONS
PLASTIC DIP
NC |
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1 |
32 |
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VCC |
A11 |
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1 |
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A9 |
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2 |
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NC |
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2 |
31 |
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WE |
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A8 |
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3 |
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A15 |
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3 |
30 |
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NC |
A13 |
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4 |
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A14 |
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5 |
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A12 |
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4 |
29 |
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A14 |
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NC |
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6 |
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A7 |
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5 |
28 |
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A13 |
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NC |
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7 |
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NC |
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8 |
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A6 |
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6 |
27 |
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A8 |
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WE |
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9 |
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A5 |
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7 |
26 |
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A9 |
VCC |
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10 |
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A4 |
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8 |
25 |
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A11 |
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NC |
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11 |
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NC |
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12 |
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X28LC512 |
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A3 |
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9 |
24 |
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NC |
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13 |
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OE |
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NC |
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14 |
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A2 |
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10 |
23 |
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A10 |
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A15 |
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15 |
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A1 |
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11 |
22 |
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CE |
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A12 |
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16 |
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A0 |
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12 |
21 |
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I/O7 |
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A7 |
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17 |
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A6 |
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18 |
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I/O0 |
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13 |
20 |
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I/O6 |
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A5 |
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19 |
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I/O1 |
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14 |
19 |
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I/O5 |
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A4 |
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20 |
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I/O2 |
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15 |
18 |
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I/04 |
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VSS |
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16 |
17 |
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I/O3 |
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3005 ILL F02.1
© Xicor, Inc. 1991, 1995, 1996 Patents Pending 3005-3.2 8/5/97 T2/C0/D0 EW
•Two PLCC and LCC Pinouts —X28LC512
—X28LC010 E 2PROM Pin Compatible —X28LC513
—Compatible with Lower Density E 2PROMs
DESCRIPTION
The X28LC512/513 is a low-power 64K x 8 E2PROM, fabricated with Xicor’s proprietary, high performance, floating gate CMOS technology. The X28LC512/513 features the JEDEC approved pinout for bytewide memories, compatible with industry standard EPROMS.
The X28LC512/513 supports a 128-byte page write operation, effectively providing a 39μs/byte write cycle and enabling the entire memory to be written in less than 2.5 seconds. The X28LC512/513 also features DATA Polling and Toggle Bit Polling, system software support schemes used to indicate the early completion of a write cycle. In addition, the X28LC512/513 supports the Software Data Protection option.
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PLCC |
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12 |
15 |
NC |
NC |
CC |
WE |
NC |
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A |
A |
V |
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30 |
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TSOP |
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A7 |
5 4 3 |
2 |
1 |
32 31 29 |
A14 |
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A6 |
6 |
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28 |
A13 |
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40 |
OE |
A5 |
7 |
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27 |
A8 |
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39 |
A10 |
A4 |
8 |
X28LC512 |
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26 |
A9 |
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38 |
CE |
A3 |
9 |
(TOP VIEW) |
25 |
A11 |
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37 |
I/O7 |
A2 |
10 |
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24 |
OE |
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36 |
I/O6 |
A1 |
11 |
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23 |
A10 |
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35 |
I/O5 |
A0 |
12 |
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22 |
CE |
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34 |
I/O4 |
I/O0 |
13 |
15 16 17 18 19 20 21 |
I/O7 |
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33 |
I/O3 |
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14 |
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32 |
NC |
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1 |
2 |
SS |
3 |
4 |
5 6 |
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X28LC512 |
31 |
NC |
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I/O |
I/O |
V |
I/O |
I/O |
I/O |
I/O |
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3005 ILL F03 |
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30 |
VSS |
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29 |
NC |
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PLCC |
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28 |
NC |
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12 |
14 |
15 |
CC |
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13 |
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27 |
I/O2 |
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7 |
WE |
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26 |
I/O1 |
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A |
A A |
A V |
A |
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30 |
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25 |
I/O0 |
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24 |
A0 |
A6 |
5 4 3 2 |
1 |
32 31 29 |
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A8 |
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23 |
A1 |
A5 |
6 |
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28 |
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A9 |
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22 |
A2 |
A4 |
7 |
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27 |
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A11 |
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21 |
A3 |
A3 |
8 |
X28LC513 |
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26 |
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NC |
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A2 |
9 |
(TOP VIEW) |
25 |
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OE |
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24 |
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3005 ILL F22.2 |
A1 |
10 |
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A10 |
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A0 |
11 |
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23 |
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CE |
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NC |
12 |
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22 |
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I/O7 |
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I/O0 |
13 |
15 16 17 18 19 20 |
21 |
I/O6 |
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14 |
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1 |
2 |
SS |
NC |
3 |
4 5 |
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I/O |
I/O |
V |
I/O |
I/O |
I/O |
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3005 ILL F04.1
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1 |
Characteristics subject to change without notice |
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X28LC512/X28LC513
PIN DESCRIPTIONS
Addresses (A –A )
0 15
The Address inputs select an 8-bit memory location during a read or write operation.
Chip Enable (CE)
The Chip Enable input must be LOW to enable all read/ write operations. When CE is HIGH, power consumption is reduced.
Output Enable (OE)
The Output Enable input controls the data output buffers and is used to initiate read operations.
Data In/Data Out (I/O –I/O)
0 7
Data is written to or read from the X28LC512/513 through the I/O pins.
FUNCTIONAL DIAGRAM
Write Enable (WE)
The Write Enable input controls the writing of data to the X28LC512/513.
PIN NAMES
Symbol |
Description |
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A0–A15 |
Address Inputs |
I/O0–I/O7 |
Data Input/Output |
WE |
Write Enable |
CE |
Chip Enable |
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OE |
Output Enable |
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VCC |
3.3V ± 10% |
VSS |
Ground |
NC |
No Connect |
3005 PGM T01
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X BUFFERS |
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512K-BIT |
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A7–A15 |
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E2PROM |
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LATCHES AND |
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ARRAY |
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DECODER |
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Y BUFFERS |
I/O BUFFERS |
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AND LATCHES |
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A0–A6 |
LATCHES AND |
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DECODER |
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I/O0–I/O7
DATA INPUTS/OUTPUTS
CE |
CONTROL |
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OE |
LOGIC AND |
WE |
TIMING |
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VCC |
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VSS |
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3005 ILL F01
2
X28LC512/X28LC513
DEVICE OPERATION
Read
Read operations are initiated by both OE and CE LOW. The read operation is terminated by either CE or OE returning HIGH. This two line control architecture eliminates bus contention in a system environment. The data bus will be in a high impedance state when either OE or CE is HIGH.
Write
Write operations are initiated when both CE and WE are LOW and OE is HIGH. The X28LC512/513 supports both a CE and WE controlled write cycle. That is, the address is latched by the falling edge of either CE or WE, whichever occurs last. Similarly, the data is latched internally by the rising edge of either CE or WE, whichever occurs first. A byte write operation, once initiated, will automatically continue to completion, typically within 5ms.
Page Write Operation
The page write feature of the X28LC512/513 allows the entire memory to be written in 2.5 seconds. Page write allows two to one hundred twenty-eight bytes of data to be consecutively written to the X28LC512/513 prior to the commencement of the internal programming cycle. The host can fetch data from another device within the system during a page write operation (change the source address), but the page address (A7 through A15) for each subsequent valid write cycle to the part during this operation must be the same as the initial page address.
The page write mode can be initiated during any write operation. Following the initial byte write cycle, the host can write an additional one to one hundred twentyseven bytes in the same manner as the first byte was written. Each successive byte load cycle, started by the WE HIGH to LOW transition, must begin within 100μs of the falling edge of the preceding WE. If a subsequent WE HIGH to LOW transition is not detected within 100μs, the internal automatic programming cycle will commence. There is no page write window limitation.
Effectively the page write window is infinitely wide, so long as the host continues to access the device within the byte load cycle time of 100μs.
Write Operation Status Bits
The X28LC512/513 provides the user two write operation status bits. These can be used to optimize a system write cycle time. The status bits are mapped onto the I/O bus as shown in Figure 1.
Figure 1. Status Bit Assignment
I/O |
DP |
TB |
5 |
4 |
3 |
2 |
1 |
0 |
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RESERVED
TOGGLE BIT
DATA POLLING
3005 ILL F11
DATA Polling (I/O7)
The X28LC512/513 features DATA Polling as a method to indicate to the host system that the byte write or page write cycle has completed. DATA Polling allows a simple bit test operation to determine the status of the X28LC512/ 513, eliminating additional interrupt inputs or external hardware. During the internal programming cycle, any attempt to read the last byte written will produce the complement of that data on I/O7 (i.e. write data = 0xxx xxxx, read data = 1xxx xxxx). Once the programming cycle is complete, I/O7 will reflect true data.
Toggle Bit (I/O6)
The X28LC512/513 also provides another method for determining when the internal write cycle is complete. During the internal programming cycle, I/O6 will toggle from HIGH to LOW and LOW to HIGH on subsequent attempts to read the device. When the internal cycle is complete the toggling will cease and the device will be accessible for additional read or write operations.
3
X28LC512/X28LC513
DATA Polling I/O7
Figure 2a. DATA Polling Bus Sequence
LAST
WE WRITE
CE |
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OE |
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VIH |
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HIGH Z |
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V |
OH |
I/O7 |
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VOL |
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X28LC512 |
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READY |
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A0–A15 |
An |
An |
An |
An |
An |
An |
An |
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3005 ILL F12
Figure 2b. DATA Polling Software Flow
WRITE DATA
WRITES NO
COMPLETE?
YES
SAVE LAST DATA
AND ADDRESS
READ LAST |
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ADDRESS |
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IO7 |
NO |
COMPARE? |
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YES |
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X28LC512 |
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READY |
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DATA Polling can effectively halve the time for writing to the X28LC512/513. The timing diagram in Figure 2a illustrates the sequence of events on the bus. The software flow diagram in Figure 2b illustrates one method of implementing the routine.
3005 ILL F13
4
X28LC512/X28LC513
The Toggle Bit I/O6
Figure 3a. Toggle Bit Bus Sequence
LAST
WE WRITE
CE |
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OE |
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I/O6 |
* |
VOH |
HIGH Z |
VOL |
* |
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X28LC512 |
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READY |
* Beginning and ending state of I/O6 will vary.
3005 ILL F14
Figure 3b. Toggle Bit Software Flow
LAST WRITE
LOAD ACCUM
FROM ADDR n
COMPARE
ACCUM WITH
ADDR n
NO
COMPARE
OK?
YES
X28LC512
READY
3005 ILL F15
The Toggle Bit can eliminate the software housekeeping chore of saving and fetching the last address and data written to a device in order to implement DATA Polling. This can be especially helpful in an array comprised of multiple X28LC512/513 memories that is frequently updated. Toggle Bit Polling can also provide a method for status checking in multiprocessor applications. The timing diagram in Figure 3a illustrates the sequence of events on the bus. The software flow diagram in Figure 3b illustrates a method for polling the Toggle Bit.
5
X28LC512/X28LC513
HARDWARE DATA PROTECTION
The X28LC512/513 provides three hardware features that protect nonvolatile data from inadvertent writes.
•Noise Protection—A WE pulse typically less than 10ns will not initiate a write cycle.
•Write Inhibit—Holding either OE LOW, WE HIGH, or CE HIGH will prevent an inadvertent write cycle during power-up and power-down, maintaining data integrity. Write cycle timing specifications must be observed concurrently.
SOFTWARE DATA PROTECTION
The X28LC512/513 offers a software controlled data protection feature. The X28LC512/513 is shipped from Xicor with the software data protection NOT ENABLED; that is, the device will be in the standard operating mode. In this mode data should be protected during power-up/ -down operations through the use of external circuits. The host would then have open read and write access of the device once VCC was stable.
The X28LC512/513 can be automatically protected during power-up and power-down without the need for
external circuits by employing the software data protection feature. The internal software data protection circuit is enabled after the first write operation utilizing the software algorithm. This circuit is nonvolatile and will remain set for the life of the device unless the reset command is issued.
Once the software protection is enabled, the X28LC512/ 513 is also protected from inadvertent and accidental writes in the powered-up state. That is, the software algorithm must be issued prior to writing additional data to the device. Note: The data in the three-byte enable sequence is not written to the memory array.
SOFTWARE ALGORITHM
Selecting the software data protection mode requires the host system to precede data write operations by a series of three write operations to three specific addresses. Refer to Figure 4a and 4b for the sequence. The three byte sequence opens the page write window enabling the host to write from one to one hundred twenty-eight bytes of data. Once the page load cycle has been completed, the device will automatically be returned to the data protected state.
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