mikroElektronika EasyPIC v7, Руководство пользователя

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Easy PIC
for dsPIC30
®
v7
page 31
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. Because of the ability to alter single bytes
of data, EEPROM devices are used to store personal
preference and configuration data in a wide spectrum
of consumer, automotive, telecommunication, medical,
industrial, and PC applications.
EasyPIC
™
v7 for dsPIC30
®
supports serial EEPROM which
uses I
2
C communication interface and has 1024 bytes
of available memory. Board contains socket for serial EEPROMs
in DIP8 packaging, so you can easily exchange it with different
memory size EEPROM IC. EEPROM itself supports single byte or 16-byte
(page) write and read operations. Data rate is 400 kHz for both 3.3V and 5V
power supply.
In order to connect I
2
C EEPROM to the
microcontroller you must place J14 (SCL) and J15
(SDA) jumpers in appropriate position. 1kΩ pull-
up resistors necessary for I
2
C communication are
already provided on SDA and SCL lines. 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.
I
2
C EEPROM
5
6
7
8
C41
100nF
VCC-BRD VCC-BRD VCC-BRD
R37
1K
R38
1K
EEPROM-SCL
EEPROM-SDA
A0
A1
A2
VSS SDA
SCL
WP
VCC
1
2
3
4
U7
24C08
J14
J15
RF3
RF8
RB4
RB5
RF7
RF2
DATA BUS
Enabling I
2
C EEPROM
What is I
2
C?
Figure 18-1:
I
2
C EEPROM lines
connected to RF3
(SCL) and RF2(SDA)
microcontroller pins
other modules