Saturday, November 19, 2011

Introduction to AVR32

The ATmega32 is a CMOS 8-bit microcontroller based on the AVR architecture. The AVR architecture was conceived by Alf-Egil Bogen and Vegard Wollan, the two founders of Atmel Norway. It belongs to the family of RISC (Reduced Instruction Set Computer). The RISC is based on the insight that simplified (as opposed to complex) instructions can provide higher performance if this simplicity enables much faster execution of each instruction.
AVR stands for Alf (Egil Bogen) and Vegard (Wollan) 's Risc processor. It is a 8-bit RISC single chip microcontroller which was developed by Atmel in 1996. The AVR was one of the first microcontroller families to use on-chip flash memory for program storage, as opposed to one-time programmable ROM, EPROM, or EEPROM used by other microcontrollers at the time. It is a modified Harvard architecture machine where program and data is stored in separate physical memory systems that appear in different address spaces, but having the ability to read data items from program memory using special instructions. By combining an 8-bit RISC CPU with In-System Self-Programmable Flash on a monolithic chip, the Atmel ATmega32 is a powerful microcontroller that provides a highly-flexible and cost-effective solution to many embedded control applications. The AVR ATmega32 truly is a robot programmer's delight!!

Features:

The main features of ATmega32 are :-
32K bytes of In-System Programmable Flash Program memory with Read-While-Write capabilities
1024 bytes EEPROM
2K byte SRAM
32 general purpose I/O lines
32 general purpose working registers
a JTAG interface for Boundaryscan
On-chip Debugging support and programming
3 flexible Timer/Counters with compare modes
Internal and External Interrupts
a serial programmable USART
a byte oriented Two-wire Serial Interface
an 8-channel, 10-bit ADC
a programmable Watchdog Timer with Internal Oscillator
an SPI serial port
6 software selectable power saving modes

Thursday, November 3, 2011

Wifi Basic

There are several kinds of hardware that may be used to implement a WiFi wireless network:
  • Wireless adapters or network interface controllers (NICs for short) are network cards with the 802.11 standard which let a machine connect to a wireless network. WiFi adapters are available in numerous formats, such as PCI cards, PCMCIA cards, USB adapters, and CompactFlash cards. A station is any device that has such a card.
  • Access points (AP for short; sometimes called hotspots) can let nearby wifi-equipped stations access a wired network to which the access point is directly connected.
The 802.11 standard defines two operating modes:
  • Infrastructure mode, in which wireless clients are connected to an access point. This is generally the default mode for 802.11b cards.
  • Ad hoc mode, in which clients are connected to one another without any access point. 
Further information fallow  this link:   http://en.kioskea.net/contents/wifi/wifimodes.php3