User`s guide
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
conguration data in a wide spectrum of consumer,
automotive, telecommunication, medical, industrial, and
PC applications.
EasyMx PRO
™
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 dependant of power supply voltage, and go up to
400 kHz for 3.3V power supply. EEPROM address on I
2
C bus is 0xA2.
other modules
page 37
I
2
C EEPROM
In order to connect I
2
C EEPROM to the
microcontroller you must enable SW13.4 and
SW13.5 switches, as shown on Figure 23-2. 4K7
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 PB2 and PB3
communication lines that could interfere with the
data signals and cause data corruption.
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 bidirectional open-drain lines, Serial Data Line (SDA) and Serial Clock (SCL), pulled
up with resistors. Data and clock lines are driven with a master 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
SW13.4
and SW13.5
switches to
enable pull-up
resistors in I
2
C
lines of Serial
EEPROM.
Figure 23-1:
Schematic of
I
2
C EEPROM
module
EasyMx PRO
v7
O
N
SW13
PB3
PB2
1 2 3 4 5
6
7 8
DATA BUS
C38
100nF
1
2
3
5 4
6
7
8
A0
A1
A2
VSSSDA
SCL
WP
VCC
U8
24AA01
VCC-3.3V VCC-3.3V VCC-3.3V
R61
2K2
R62
2K2
VCC-3.3V
EEPROM-SCL
EEPROM-SDA