226 Class 1.ppt) - University of Rhode Island
Transcript of 226 Class 1.ppt) - University of Rhode Island
1
ELE492 – Embedded System Design
Class 1
6/27/06
Eugene Chabot
Outline
� Overview of microcontrollers
� Definition of embedded systems
� Examples of embedded systems
� Development Tools
� Creating a MPLAB project
� Building a basic PIC circuit
ENIAC (electronic numerical integrator and computer)
� first electronic digital computer
Source: ftp.arl.army.mil
Intel 4004
� Integrated
Electronics
� Intel was well
known for RAM technology
� Developed 4004 for
Busicom, which wanted it to replace ASICs in
their calculatorSource: en.wikipedia.org
� Executed programs stored in an
external memory
2
What is a microcontroller?
� Similar to a microprocessor
� CPU executes programs
� Programs stored in a RAM or ROM
� TI called it a computer-on-a-chip
� Microprocessor requires external parts:
� Memory
� ‘Glue logic’ – ex. address decoder and buffer chips
� Peripheral chips
Microprocessor vs Microcontroller
vs
Why do we use them?
� Inexpensive (all on one IC) VLSI design
� Small footprint
� Low number of connections
� Resources fit for application
� Faster time to market (compared to custom ICs)
What type of microcontrollers are out there?
� Intel (4004 in ~1970,8051 in ~1980)� 8051 architecture widely produced today
� Zilog (Z8,Z80 derivatives)� Used in the 1970’s for home computers
� Architecture is still used today
� Motorola (68HC11) –phased out for other product lines
� Microchip (division acquired from GI in 1989)
3
Microchip
� Major player
� 4 billionth PIC sold last year
� Success attributed to:
� Low cost
� Many peripherals
� Development tools
� Lots of documentation
Microchip (Cont’d)
� PIC – Programmable Intelligent Computer
# instr# pinsSeriesClass
7718-80PIC18High Perf.
358-64PIC12,PIC16Mid-Range
336-28PIC10,PIC12,PIC16
Baseline
Microchip (Cont’d)
� Harvard Architecture – separation of data and program memory
� RISC vs CISC
What is an Embedded System?
� A microprocessor (or microcontroller) based system designed to perform one or more specific tasks.
� “Any mechanical or electrical system that is controlled by a computer working as part of an overall system is called an embedded system.” –Steven Barrett
4
Examples of Embedded Systems
Microwaves, toasters, stoves, alarm clocks, remote controls, cell phones, thermostat control, car control systems (ABS, cruise control, navigation systems, radio,…), computer components, network routers/firewalls, copiers, printers, oscilloscopes, medical equipment, …
Special considerations of ES
� Real-Time Execution
� Development and testing environment
� Power Consumption
� User Interface
� Manufacturing Cost
� Limited Memory
� Hardware/software trade-offs
Development Tools
� PIC 18F452 (40 pin DIP)
� Up to 40MHz clock operation (10MIPS)
� 32K ROM (16K Single Word Instructions)
� 1.5KB RAM
� 256Bytes of EEPROM
� 8 10bit D/A converters, Serial, PWM, etc
Development Tools (Cont’d)
� MPLAB IDE
� Program
� Compile
� Simulate
� Debug
� Download
5
Development Tools (Cont’d)
� PICSTART+
� ZIF Socket
� Serial
� MCP
� ICSP
� USB
Source: www.olimex.com
Source: www.microchip.com
Development Tools (Cont’d)
� ICD2
� Program
� Erase
� Debug
� USB/Serial
� ICSP only
Source: www.olimex.com
Development Tools (Cont’d)
� Ceramic Resonator
� 4MHz clock input
� Includes internal
capacitors
� Works when hooked up
in either direction
CLK
GN
D
CLK
Development Tools (Cont’d)
� 5V Regulator (7805)
� Connect 9V battery
� Use Caps to clean up power
on power supplies or long
traces
In (9
V)
GN
D
Out (5
V)
6
Schematic
PIC18F452
ICSP
Header