Programmer Manual

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®
www.digilentinc.com
1/31/2006 215 E Main Suite D | Pullman, WA 99163
[phone] Voice and Fax
Doc: 506-006 page 1 of 8
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Introduction
The Digilent AVR Programmer is a Microsoft
®
Windows
® application used for in-system
programming of Atmel AVR
® microcontrollers.
It is specifically designed for programming
AVR devices on Digilent products, but is also a
general purpose AVR device programmer for
those AVR devices that support the serial in-
system programming protocol.
The AVR Programmer supports the in-system
programming of Atmel AVR devices using a
programming cable connected to a 6-pin
programming connector on the target board.
All Digilent products with a AVR microcontroller
have a suitable connector.
Installation Information
The AVR Programmer is installed by running
the Windows installer application available for
download from the Digilent web site.
The installer will copy the application program
files, required device drivers, AVR Part
Description files, and documentation file to the
user’s computer.
The part description files are copied to the
folder: Program Files\Common
Files\Digilent\AvrParts.
Overview of AVR Microcontrollers
The Atmel AVR devices are 8-bit
microcontrollers with various I/O peripheral
functions and varying amounts of program and
data memory.
There are two different ways that AVR devices
can be programmed. High-voltage parallel
programming involves placing the AVR device
into a special device programmer. This can
only be done before the device is soldered to a
PC board. In-system programming uses a
serial interface and an in-system programming
protocol to program the devices in circuit. Any
AVR device can be programmed using the
parallel programming method. Most, but not all,
AVR devices also support the in-system
programming method. The AVR Programmer
only works with in-system programming.
There are four basic parts of an AVR device
that can be programmed: the program flash,
the data EEPROM, fuses, and lock bits.
The program flash holds program instructions
to be executed. The data EEPROM is non-
volatile memory that can be programmed via
the in-system programming protocol, and can
also be read or written by the program running
on the device. Program flash and data
EEPROM are configured using the Program
tab in the AVR Programmer.
Fuses and lock bits are used to select the
device’s operating modes. They are described
in more detail below.
Before programming the flash or EEPROM
memory, you must first erase the device. When
flash or EEPROM memory are erased, the bits
are set to the 1 state. When programming, 0
bits are programmed to 0 and 1 bits are left
unchanged. It is not possible to program a bit
from 0 to 1. This can only be accomplished by
erasing.
Flash and EEPROM memory can only be
erased and reprogrammed a limited number of
times before they wear out. Atmel rates the
memories in the AVR parts as having an
endurance of 10,000 erase/reprogram cycles.
Programming over already-programmed bits
will wear them out prematurely. The AVR
Programmer allows you to manually erase the
device and has an option to automatically
erase the device while programming.