Datasheet

page 37
v7
EEPROM is short for Electrically Erasable
Programmable Read Only Memory. It is
usually a secondary storage memory in devices
containing data that is retained even if the device
looses power supply. EEPROMs come with parallel
or serial interface to the master device. Because
of the ability to alter single bytes of data, EEPROM
devices are used to store personal preference and
conguration data in a wide spectrum of consumer,
automotive, telecommunication, medical, industrial, and
PC applications.
EasyPIC Fusion
™
v7 supports serial EEPROM which uses I
2
C
communication interface and has 1024 bytes of available memory.
EEPROM itself supports single byte or 16-byte (page) write and read
operations. Data rates are dependent of power supply voltage, and go up to
400 kHz for 3.3V power supply.
other modules
I
2
C EEPROM
In order to connect I
2
C EEPROM to the
microcontroller you must enable SW14.3 and
SW14.4 or SW14.5 and SW14.6 switches. 2K2
pull-up resistors necessary for I
2
C communication
are already provided on SDA and SCL lines once
switches are turned on. Prior to using EEPROM in
your application, make sure to disconnect other
peripherals, LEDs and additional pull-up or pull-
down resistors from the interface lines in order
not to interfere with signal/data integrity.
I
2
C is a multi-master serial single-ended bus that is used to attach low-speed peripherals to computer or embedded
systems. I²C uses only two open-drain lines, Serial Data Line (SDA) and Serial Clock (SCL), pulled up with
resistors. SCL line is driven by a master, while SDA is used as bidirectional line either by master or slave device.
Up to 112 slave devices can be connected to the same bus. Each slave must have a unique address.
Enabling I
2
C EEPROM
What is I
2
C?
Figure 23-2:
Activate
SW14.3 and
SW14.4 or
SW14.5 and
SW14.6
switches
Figure 23-1:
Schematic of
I
2
C EEPROM
module
C36
100nF
1
2
3
54
6
7
8
A0
A1
A2
VSS SDA
SCL
WP
VCC
U9
24AA01 EEPROM
VCC-3.3VVCC-3.3V
VCC-3.3V
R72
2K2
R73
2K2
VCC-3.3V
EEPROM-SCL
EEPROM-SDA
EEPROM-SDA
EEPROM-SDA
EEPROM-SCL
EEPROM-SCL
1 2 3 4 5 6 7 8
O
N
SW14
RA2
RA3
DATA BUS