Using AVR Studio

AVR STK500 User Guide 5-3

1925C–AVR–3/03

5.3.1.4 EEPROM If the STK500 user interface is opened without a project loaded in AVR Studio, the “Use

Current Simulator/Emulator EEPROM Memory” option will be grayed out. When a

project is open, this option allows programming of the EEPROM memory content cur-

rently present in the EEPROM Memory view. For more information about AVR Studio

memory views, please take a look in the AVR Studio Help file.

If no project is running, or the source code is stored in a separate hex file, select the

“Input HEX File” option. Browse to the correct file by pressing the button or type the

complete path and filename in the text field. The selected file must be in “Intel-hex” for-

mat or “extended Intel-hex” format.

5.3.2 “Fuses” Settings In the “Fuses” tab an overview of accessible fuses are presented. Some fuses are only

available during High-voltage Programming. These will be displayed but not accessible

if operating in ISP programming mode. Press the “Read” button to read the current

value of the fuses, and the “Write” button to write the current fuse setting to the device.

Checking one of these check boxes indicates that this fuse should be enabled/pro-

grammed, which means writing a “0” to the fuse location in the actual device. Note that

the selected fuse setting is not affected by erasing the device with a chip-erase cycle

(i.e., pressing “Chip Erase” button in the “Program” settings).

Detailed information on what fuses are available in the different programming modes

and their functions can be found in the appropriate device datasheet.

Figure 5-3. Fuses

Using AVR Studio

5-4 AVR STK500 User Guide

1925C–AVR–3/03

5.3.3 “LockBits” Settings Similar to the “Fuses” tab, the “LockBits” tab shows which lock modes are applicable to

the selected device. All lock bits are accessible in both ISP and High-voltage Program-

ming. A lock mode may consist of a combination of setting multiple Lock bits. This is

handled by the STK500 user interface, and the correct lock bits are programmed auto-

matically for the selected lock mode. Once a Lock mode protection level is enabled, it is

not possible to lower the protection level by selecting a “lower” degree of protection or

by setting a different Lock mode. The only way to remove a programmed Lock bit is to

perform a complete chip erase, erasing both program and data memories. One excep-

tion exists: If the target device has a programmed “EESAVE” fuse, the contents of the

EEPROM will be saved even though a complete chip erase on the device is performed.

Figure 5-4. LockBits

5.3.4 “Advanced”

Settings

The “Advanced” tab is currently divided into two subgroups.

5.3.4.1 Signature Bytes By pressing the “Read Signature” button, the signature bytes are read from the target

device. The signature bytes act like an identifier for the part. After reading the signature,

the software will check if it is the correct signature according to the chosen device.

Please refer to the AVR datasheets to read more about signature bytes.

Using AVR Studio

AVR STK500 User Guide 5-5

1925C–AVR–3/03

Figure 5-5. Advanced

5.3.4.2 Oscillator

Calibration Byte

The oscillator calibration byte is written to the device during manufacturing, and cannot

be erased or altered by the user. The calibration byte is a tuning value that should be

written to the OSCCAL register in order to tune the internal RC oscillator.

5.3.4.3 Reading Oscillator

Calibration Byte

By pressing the “Read Cal. Byte” button, the calibration value is read from the device

and is shown in the “Value” text box. Note that the calibration byte is not directly acces-

sible during program execution and must be written to a memory location during

programming if it shall be used by the program. If this option is grayed out, the selected

device does not have a tunable internal RC oscillator.

5.3.4.4 Writing Oscillator

Calibration Byte

Since the calibration byte is not directly accessible during program execution, the user

should write the calibration byte into a known location in Flash or EEPROM memory. Do

this by writing the desired memory address in the “Write Address” text box and then

press the “Write to Memory” button. The calibration byte is then written to the memory

indicated by the “Flash” and “Eeprom” radio buttons.

5.3.5 “Board” Settings The “Board” tab allows the changing of operating conditions on the STK500 develop-

ment board. The following properties can be modified: VTARGET, AREF and oscillator

frequency.

The interface is very flexible and it is possible to force the operating conditions beyond

the recommended specifications for the device. Doing this is not recommended, and

may damage the target device. The recommended operating conditions for the part are

stated in the device datasheet.

Part #	C1925
Description	BLOCK, JUNCTION - Bulk
Category	HARDWARE
Availability	In Stock
Qty	2

C1925

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