15-05-2013, 11:53 AM
OVERVIEW OF ARCHITECTURE & MICROCONTROLLER RESOURCES
[attachment=53909]
Central Processing Unit (CPU)
It is the hardware within a computer system which carries out the instructions of a computer program by performing the basic arithmetical, logical, and input/output operations of the system
General-purpose microprocessor
CPU for Computers
No RAM, ROM, I/O on CPU chip itself
Example：Intel’s x86, Motorola’s 680x0
Three criteria in Choosing a Microcontroller
Meeting the computing needs of the task efficiently and cost effectively
speed, the amount of ROM and RAM, the number of I/O ports and timers, size, packaging, power consumption
easy to upgrade
cost per unit
Availability of software development tools
assemblers, debuggers, C compilers, emulator, simulator, technical support
Wide availability and reliable sources of the microcontrollers.
Microcontroller Resources
BUS WIDTH
Internal (Fixed)
8 BIT for 8051
16 BIT for 68HC11
External (Optional)
8 BIT Data bus (for 8051 & 68HC11)
16 BIT Address BUS (for 8051/68HC11)
PROGRAM AND DATA MEMORIES
Program Memory
Programs, routines, ISRs
Permanent constants like standard messages
String data for example welcome messages and operational menus
Modifiable constants, for example password, user id, calibration constants
Data Memory
On chip RAM for variables, pointers, lookup tables
On Chip registers (SFRs) for port/device control
External RAM for large buffers, queues, etc address indirectly
PARALLEL PORTS
8BIT on chip ports
Programmable as input/output
Individual bits accessible (or ) modifiable
Simple I/O Port (P1 of 8051)
Port with buffer/latch (P0, P2 of 8051)
Port with data direction control (Port C&D of 68HC11)
Port with analog input capability (PORT E of 68HC11)
Port with hand shaking signals (PORT C of 68HC11)
Open drain port (Requires external pullup ). P1 of 8051
Quasi by directional (external pull-ups not required).P0,P2,P3 of 8051
[attachment=53909]
Central Processing Unit (CPU)
It is the hardware within a computer system which carries out the instructions of a computer program by performing the basic arithmetical, logical, and input/output operations of the system
General-purpose microprocessor
CPU for Computers
No RAM, ROM, I/O on CPU chip itself
Example：Intel’s x86, Motorola’s 680x0
Three criteria in Choosing a Microcontroller
Meeting the computing needs of the task efficiently and cost effectively
speed, the amount of ROM and RAM, the number of I/O ports and timers, size, packaging, power consumption
easy to upgrade
cost per unit
Availability of software development tools
assemblers, debuggers, C compilers, emulator, simulator, technical support
Wide availability and reliable sources of the microcontrollers.
Microcontroller Resources
BUS WIDTH
Internal (Fixed)
8 BIT for 8051
16 BIT for 68HC11
External (Optional)
8 BIT Data bus (for 8051 & 68HC11)
16 BIT Address BUS (for 8051/68HC11)
PROGRAM AND DATA MEMORIES
Program Memory
Programs, routines, ISRs
Permanent constants like standard messages
String data for example welcome messages and operational menus
Modifiable constants, for example password, user id, calibration constants
Data Memory
On chip RAM for variables, pointers, lookup tables
On Chip registers (SFRs) for port/device control
External RAM for large buffers, queues, etc address indirectly
PARALLEL PORTS
8BIT on chip ports
Programmable as input/output
Individual bits accessible (or ) modifiable
Simple I/O Port (P1 of 8051)
Port with buffer/latch (P0, P2 of 8051)
Port with data direction control (Port C&D of 68HC11)
Port with analog input capability (PORT E of 68HC11)
Port with hand shaking signals (PORT C of 68HC11)
Open drain port (Requires external pullup ). P1 of 8051
Quasi by directional (external pull-ups not required).P0,P2,P3 of 8051