Atmel AVR STK500, User Manual

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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.