How to use avrStudio to..

How to use avrStudio to get the output on portc for example i try to use log file
i.e portc.log but no output and why there isn`t waveform output is there is anther simulation contain that i have ATMEGA8515

As I know, You can see the PORTC register when the program is running and Ii'm not sure you can view the log file

Added after 1 hours 35 minutes:

In AVR Studio, you can read Simulator User's Guide include:
- Simulator Option
- Simulator I/O Module
- Port Logging and Stimuli:

Logging Ports
The user can log the activity on the output ports. If Simulator Port Logging is selected from the Options menu, the log files dialog appears on the screen.

The user must select which of the Ports to log. If a Port is selected, the user must also select the file to place the logged data on. It is the contents of the Port’s PORT register which is placed on the file. Each line of the log file has the following format: Cycleata. The Cycle field is in decimal format and the Data field is in hexadecimal format. If the contents of the port register is unchanged in a cycle, no output is produced.

The log files are deleted each time the program is reset. Logging must be activated manually each time a program is loaded into AVR Studio.

External Stimuli
The user can set values on the ports. If Simulator Port Stimuli is selected from the Options menu, the stimuli file dialog appears on the screen.

If a Port is selected, the user must inform where the stimuli file is placed. The values in the stimuli file are placed in the PIN register on the specified port on the specified cycle. The format of the stimuli file is the same as for the Port logging. Note that only pins set as inputs are affected.

The last line of the stimuli file must be like this: 9999999999:FF (A large number before the :FF), otherwise an error will occur.