19-01-2013, 01:26 PM
INTERFACING OF EEPROM WITH SPI PROTOCOL
INTERFACING OF EEPROM.ppt (Size: 1.38 MB / Downloads: 75)
ABSTRACT
By using the SPI protocols the EEPROM is interfaced with the LPC2148 microcontroller. To display the data stored in the EEPROM we use the LCD display and a matrix keyboard to enter the data into the EEPROM.
REQUIREMENTS
Matrix keypad to send the data that has to be stored into EEPROM(93C46).
LCD to display the data which we is stored in EEPROM.
LPC2148 Micro controller is used.
Data is transferred and received between LPC2148 and EEPROM by using SPI protocol.
LPC2148
The LPC2148 microcontroller is based on 32/16 bit ARM7TDMI-S CPU.
A 128-bit wide memory interface and unique accelerator architecture enable 32-bit code execution at the maximum clock rate.
16-bit Thumb mode reduces code by more than 30% with minimal performance penalty.
SPECIFICATIONS
16/32-bit ARM7TDMI-S microcontroller in a tiny LQFP64 package.
8 to 40 kB of on-chip static RAM and 32 to 512 kB of on-chip Flash program memory.128 bit wide interface/accelerator enables high speed 60 MHz operation.
One or two (LPC2141/2 vs. LPC2144/6/8) 10-bit A/D converters with conversion times as low as 2.44 µs per channel.
Two 32-bit timers/external event counters. PWM unit (six outputs) and watchdog.
60 MHz maximum CPU clock available from programmable on-chip Phase-Locked Loop (PLL) with settling time of 100 µs.
Vectored interrupt controller with configurable priorities and vector addresses.
60 MHz maximum CPU clock available.
Processor wake-up from Power-down mode via external interrupt, USB, Brown - Out Detect (BOD) or Real-time Clock.
SPI PROTOCOL IN ARM
SPI module in LPC2138 is characterized with 4-pins and 5-registers.
The SPI is illustrated with CPOL set to both 0 and 1.
When CPHA = 0, the SSEL signal will always go inactive between data transfers.
This is not guaranteed when CPHA = 1 (the signal can remain active).
LCD
LCD (Liquid Crystal Display) screen is an electronic display module and find a wide range of applications.
A 16x2 LCD means it can display 16 characters per line and there are 2 such lines. In this LCD each character is displayed in 5x7 pixel matrix. This LCD has two registers, namely, Command and Data.
The command register - To do a predefined task.
The data register - To store the data.
The data is the ASCII value of the character to be displayed on the LCD.
In the backside of LCD, a PCB is attached which contains the required circuitry to process the signals. The key component of the circuitry is a controller and memory in the form of COB IC.
PCB : PCBs are a composite of organic and/or inorganic dielectric materials with many layers with wiring interconnects and also house components like inductors and capacitors
COB IC : Chip-on-Board (COB) a semiconductor chip is placed directly on a PCB, eliminating the packaging step.
APPLICATIONS
By using SPI we can send the data with MBPS speed.
It is Full Duplex communications.
Mainly used for short distance communications