©
1996 Microchip Technology Inc.
DS21125B-page 1
FEATURES
• Voltage operating range: 4.5V to 5.5V
- Maximum write current 3 mA at 5.5V
- Maximum read current 150
µ
A at 5.5V
- Standby current 1
µ
A typical
• 1 MHz SE2.bus two wire protocol
• Up to eight devices may be connected to the
same bus for up to 512K bits total memory
• Programmable block security options
• Programmable endurance options
• Schmitt trigger inputs for noise suppression
• Self-timed ERASE and WRITE cycles
• Power on/off data protection circuitry
• Endurance:
- 10,000,000 E/W cycles guaranteed for a 4K
block
- 1,000,000 E/W cycles guaranteed for a 60K
block
• Variable page size up to 64 bytes
• 8 byte x 8 line input cache (64 bytes)
for fast write loads
• <3 ms typical write cycle time, byte or page
• Electrostatic discharge protection > 4000V
• Data retention > 200 years
• 8-pin PDIP/SOIC packages
• Temperature ranges
DESCRIPTION
The Microchip Technology Inc. 24FC65 is a “smart”
8K 8x 8 Serial Electrically Erasable PROM (EEPROM)
with a high-speed 1MHz SE2.bus whose protocol is
functionally equivalent to the industry-standard I
2
C bus.
This device has been developed for advanced applica-
tions such as personal communications, and provides
the systems designer with flexibility through the use of
many new user-programmable features. The 24FC65
offers a relocatable 4K-bit block of ultra-high-endurance
memory for data that changes frequently. The remain-
der of the array, or 60K bits, is rated at 1,000,000
ERASE/WRITE (E/W) cycles guaranteed. The 24FC65
features an input cache for fast write loads with a
capacity of eight pages, or 64 bytes. This device also
features programmable security options for E/W pro-
- Commercial (C):
0
°
C to +70
°
C
- Industrial (I):
-40
°
C to +85
°
C
tection of critical data and/or code of up to fifteen 4K
blocks. Functional address lines allow the connection of
up to eight 24FC65's on the same bus for up to 512K bits
contiguous EEPROM memory. The 24FC65 is available
in the standard 8-pin plastic DIP and 8-pin surface
mount SOIC package.
24FC65
64K 5.0V 1 MHz I
2
C
™
Smart Serial
™
EEPROM
PACKAGE TYPES
BLOCK DIAGRAM
24FC65
A0
A1
A2
V
SS
1
2
3
4
8
7
6
5
V
CC
NC
SCL
SDA
24FC65
A0
A1
A2
V
SS
1
2
3
4
8
7
6
5
V
CC
NC
SCL
SDA
PDIP
SOIC
A0..A2
I/O
CONTROL
LOGIC
I/O
SDA
SCL
Vcc
Vss
MEMORY
CONTROL
LOGIC
XDEC
HV GENERATOR
EEPROM
ARRAY
PAGE LATCHES
YDEC
CACHE
SENSE AMP
R/W CONTROL
I
2
C is a trademark of Philips Corporation.
Smart Serial is a trademark of Microchip Technology Inc.
This document was created with FrameMaker 4 0 4
24FC65
DS21125B-page 2
©
1996 Microchip Technology Inc.
1.0
ELECTRICAL CHARACTERISTICS
1.1
Maximum Ratings*
V
CC
...................................................................................7.0V
All inputs and outputs w.r.t. V
SS
............... -0.6V to V
CC
+1.0V
Storage temperature .....................................-65
°
C to +150
°
C
Ambient temp. with power applied ................-65
°
C to +125
°
C
Soldering temperature of leads (10 seconds) ............. +300
°
C
ESD protection on all pins
..................................................≥
4 kV
*Notice:
Stresses above those listed under “Maximum Ratings”
may cause permanent damage to the device. This is a stress rat-
ing 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:
PIN FUNCTION TABLE
Name
Function
A0..A2
User Configurable Chip Selects
V
SS
Ground
SDA
Serial Address/Data I/O
SCL
Serial Clock
V
CC
+4.5V to 5.5V Power Supply
NC
No Internal Connection
TABLE 1-2:
DC CHARACTERISTICS
FIGURE 1-1:
BUS TIMING START/STOP
V
CC
= +4.5V to +5.5V
Commercial (C): Tamb = 0
°
C to +70
°
C
Industrial (I):
Tamb = -40
°
C to +85
°
C
Parameter
Symbol
Min
Max
Units
Conditions
A0, A1, A2, SCL and SDA pins:
High level input voltage
Low level input voltage
Hysteresis of SCL and SDA
Low level output voltage of SDA
V
IH
V
IL
V
HYS
V
OL
0.7 V
CC
—
0.05 V
CC
—
—
0.3 Vcc
—
0.40
V
V
V
V
(Note)
I
OL
= 3.0 mA
Input leakage current
I
LI
-10
10
µ
A
V
IN
= 0.1V to V
CC
Output leakage current
I
LO
-10
10
µ
A
V
OUT
= 0.1V to V
CC
Pin capacitance
(all inputs/outputs)
C
INT
—
10
pF
V
CC
= 5.0V (Note)
Tamb = 25˚C, F
CLK
= 1 MHz
Operating current
I
CC
Write
I
CC
Read
—
—
3
150
mA
µ
A
V
CC
= 5.5V, SCL = 1 MH
Z
V
CC
= 5.5V, SCL = 1 MHz
Standby current
I
CCS
—
5
(1 typical)
µ
A
V
CC
= 5.5V, SCL = SDA =V
CC
(Note)
Note:
This periodically sampled and not 100% tested.
SCL
SDA
START
STOP
V
HYS
T
SU
:
STO
T
HD
:
STA
T
SU
:
STA
This document was created with FrameMaker 4 0 4
©
1996 Microchip Technology Inc.
DS21125B-page 3
24FC65
TABLE 1-3:
AC CHARACTERISTICS
FIGURE 1-2:
BUS TIMING DATA
Parameter
Symbol
1 MHz Bus
Units
Remarks
Min
Max
Clock frequency
F
CLK
0
1000
kHz
Clock high time
THIGH
500
—
ns
Clock low time
T
LOW
500
—
ns
SDA and SCL rise time
T
R
—
300
ns
(Note 1)
SDA and SCL fall time
T
F
—
100
ns
(Note 1)
START hold time
T
HD
:
STA
250
—
ns
After this period the first clock pulse is
generated
START setup time
T
SU
:
STA
250
—
ns
Only relevant for repeated START
Data input hold time
T
HD
:
DAT
0
—
ns
Data input setup time
T
SU
:
DAT
100
—
ns
STOP setup time
T
SU
:
STO
250
—
ns
Output valid from clock
T
AA
—
350
ns
(Note 2)
Bus free time
T
BUF
500
—
ns
Time the bus must be free before a
new transmission can start
Write cycle time
T
WR
—
5
ms/page (Note 3)
Endurance
High Endurance Block
Rest of Array
10M
1M
—
—
cycles
25
°
Note 1: Not 100 percent tested.
2: As a transmitter, the device must provide an internal minimum delay time to bridge the undefined region (min-
imum 100 ns) of the falling edge of SCL to avoid unintended generation of START or STOPs.
3: The times shown are for a single page of 8 bytes. Multiply by the number of pages loaded into the write cache
for total time.
4: This parameter is not tested but guaranteed by characterization. For endurance estimates in a specific appli-
cation, please consult the Total Endurance Model which can be obtained on our BBS or website.
SCL
SDA
IN
SDA
OUT
T
SU
:
STA
T
SP
T
AA
T
F
T
LOW
T
HIGH
T
HD
:
STA
T
HD
:
DAT
T
SU
:
DAT
T
SU
:
STO
T
BUF
T
AA
T
R
24FC65
DS21125B-page 4
©
1996 Microchip Technology Inc.
2.0
FUNCTIONAL DESCRIPTION
The 24FC65 supports a bidirectional two-wire bus and
data transmission protocol. A device that sends data
onto the bus is defined as transmitter, and a device
receiving data as receiver. The bus must be controlled
by a master device which generates the serial clock
(SCL), controls the bus access, and generates the
START and STOPs, while the 24FC65 works as slave.
Both master and slave can operate as transmitter or
receiver but the master device determines which mode
is activated.
3.0
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.
Accordingly, the following bus conditions have been
3.1
Bus not Busy (A)
Both data and clock lines remain HIGH.
3.2
Start Data Transfer (B)
A HIGH to LOW transition of the SDA line while the
clock (SCL) is HIGH determines a START. All
commands must be preceded by a START.
3.3
Stop Data Transfer (C)
A LOW to HIGH transition of the SDA line while the
clock (SCL) is HIGH determines a STOP. All operations
must be ended with a STOP.
3.4
Data Valid (D)
The state of the data line represents valid data when,
after a START, 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.
Each data transfer is initiated with a START and
terminated with a STOP. The number of the data bytes
transferred between the START and STOPs is
determined by the master device.
3.5
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.
A device that acknowledges must 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.
During reads, 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 (24FC65) must leave the data line
HIGH to enable the master to generate the STOP.
Note:
The 24FC65 does not generate any
acknowledge bits if an internal program-
ming cycle is in progress.
FIGURE 3-1:
DATA TRANSFER SEQUENCE ON THE SERIAL BUS
SCL
SDA
(A)
(B)
START
(C)
(A)
(D)
(D)
Address
or
Acknowledge
Valid
Data Allowed
to Change
STOP
Condition
Condition
©
1996 Microchip Technology Inc.
DS21125B-page 5
24FC65
3.6
Device Addressing
A control byte is the first byte received following the
START from the master device. The control byte consists
of a four bit control code, for the 24FC65 this is set as
1010 binary for read and write operations. The next three
bits of the control byte are the device select bits (A2, A1,
A0). They are used by the master device to select which
of the eight devices are to be accessed. These bits are
in effect the three most significant bits of the word
address. The last bit of the control byte (R/W) defines the
operation to be performed. When set to a one a read
operation is selected, when set to a zero a write opera-
tion is selected. The next two bytes received define the
A12..A0 are used, the upper three address bits must be
zeros. The most significant bit of the most significant byte
is transferred first. Following the START, the 24FC65
monitors the SDA bus checking the device type identifier
being transmitted. Upon receiving a 1010 code and
appropriate device select bits, the slave device (24FC65)
outputs an acknowledge signal on the SDA line.
Depending upon the state of the R/W bit, the 24FC65 will
select a read or write operation.
FIGURE 3-2:
CONTROL BYTE
ALLOCATION
Operation
Control
Code
Device Select
R/W
Read
1010
Device Address
1
Write
1010
Device Address
0
SLAVE ADDRESS
X = Don’t care
1
0
1
0
A2
A1
A0
R/W
A
START
READ/WRITE
4.0
WRITE OPERATION
4.1
Byte Write
Following the START from the master, the control code
(four bits), the device select (three bits), and the R/W bit
which is a logic low is placed onto the bus by the master
transmitter. This indicates to the addressed slave
receiver (24FC65) 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 high-order byte of the word address
and will be written into the address pointer of the
24FC65. The next byte is the least significant address
byte. After receiving another acknowledge signal from
the 24FC65 the master device will transmit the data word
to be written into the addressed memory location. The
24FC65 acknowledges again and the master generates
a STOP. This initiates the internal write cycle, and during
this time the 24FC65 will not generate acknowledge sig-
4.2
Page Write
The write control byte, word address and the first data
byte are transmitted to the 24FC65 in the same way as
in a byte write. But instead of generating a STOP the
master transmits up to eight pages of eight data bytes
each (64 bytes total) which are temporarily stored in the
on-chip page cache of the 24FC65. They will be written
from the cache into the EEPROM array after the master
has transmitted a STOP. After the receipt of each word,
the six lower order address pointer bits are internally
incremented by one. The higher order seven bits of the
word address remain constant. If the master should
transmit more than eight bytes prior to generating the
STOP (writing across a page boundary), the address
counter (lower three bits) will roll over and the pointer will
be incremented to point to the next line in the cache. This
can continue to occur up to eight times or until the cache
is full, at which time a STOP should be generated by the
master. If a STOP is not received, the cache pointer will
roll over to the first line (byte 0) of the cache, and any
further data received will overwrite previously captured
data. The STOP can be sent at any time during the
transfer. As with the byte write operation, once the STOP
is received an internal write cycle will begin. The 64 byte
cache will continue to capture data until a STOP occurs
FIGURE 4-1:
BYTE WRITE
BUS ACTIVITY
MASTER
SDA LINE
BUS ACTIVITY
CONTROL
BYTE
WORD
ADDRESS (1)
A
C
K
S
T
A
R
T
WORD
ADDRESS (0)
A
C
K
A
C
K
0
S
T
O
P
A
C
K
0 0
DATA
24FC65
DS21125B-page 6
©
1996 Microchip Technology Inc.
FIGURE 4-2:
FIGURE 4-3:
CURRENT ADDRESS READ
FIGURE 4-4:
RANDOM READ
FIGURE 4-5:
SEQUENTIAL READ
BUS
MASTER
SDA LINE
BUS
CONTROL
BYTE
WORD
ADDRESS (1)
S
T
O
P
S
T
A
R
T
A
C
K
0
A
C
K
A
C
K
ACTIVITY:
ACTIVITY:
A
C
K
A
C
K
DATA n
DATA n+7
0 0
WORD
ADDRESS (0)
CONTROL
A
C
K
S
T
A
R
T
S
T
O
P
BYTE
DATA n
BUS ACTIVITY
MASTER
SDA LINE
BUS ACTIVITY
A
C
K
N
O
BUS
MASTER
SDA LINE
BUS
CONTROL
BYTE
WORD
ADDRESS (1)
S
T
O
P
S
T
A
R
T
A
C
K
A
C
K
A
C
K
ACTIVITY:
ACTIVITY:
A
C
K
N
O
DATA n
0 0 0
WORD
ADDRESS (0)
S
T
A
R
T
CONTROL
BYTE
A
C
K
A
C
K
BUS ACTIVITY
MASTER
SDA LINE
BUS ACTIVITY
CONTROL
BYTE
DATA n
DATA n+1
DATA n+2
DATA n+X
A
C
K
A
C
K
A
C
K
N
O
A
C
K
S
T
O
P
©
1996 Microchip Technology Inc.
DS21125B-page 7
24FC65
5.0
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.
5.1
Current Address Read
The 24FC65 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 (n is any legal address), 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 24FC65 issues an acknowledge
and transmits the eight bit data word. The master will
not acknowledge the transfer but does generate a
STOP and the 24FC65 discontinues transmission
5.2
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
24FC65 as part of a write operation (R/W bit set to 0).
After the word address is sent, the master generates a
START 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 24FC65 will
then issue an acknowledge and transmit the eight bit
data word. The master will not acknowledge the transfer
but does generate a STOP which causes the 24FC65
5.3
Sequential Read
Sequential reads are initiated in the same way as a
random read except that after the 24FC65 transmits the
first data byte, the master issues an acknowledge as
opposed to the STOP used in a random read. This
acknowledge directs the 24FC65 to transmit the next
Following the final byte transmitted to the master, the
master will NOT generate an acknowledge but will
generate a STOP.
To provide sequential reads the 24FC65 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.
5.4
Contiguous Addressing Across
Multiple Devices
The device select bits A2, A1, A0 can be used to
expand the contiguous address space for up to
512K-bits by adding up to eight 24FC65's on the same
bus. In this case, software can use A0 of the control
byte as address bit A13, A1 as address bit A14, and A2
as address bit A15.
5.5
Noise Protection
The SCL and SDA inputs incorporate Schmitt triggers
which suppress noise spikes to assure proper device
operation even on a noisy bus.
5.6
High Endurance Block
The location of the high-endurance block within the
memory map is programmed by setting the leading bit
7 (S/HE) of the configuration byte to 0. The upper bits
of the address loaded in this command will determine
which 4K block within the memory map will be set to
of 10,000,000 erase/write cycles guaranteed.
5.7