Logging Ports 
The user can log the activity on the output ports to a file or to the output window. 
The user must select which of the Ports to log. If a Port is selected, the user must
 also select the file (or screen) 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: 

Cycle:Data

IMPORTANT: The Cycle field is in decimal format and the Data field is in hexadecimal
 format. Maximum 9 digits for the cycle value. 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, settings are not saved between project sessions.


External Stimuli 
The user can set values on any of the available ports from a file. 
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. Example:
000000000:00
000000009:AB
000000014:AC

Note that only pins set as inputs are affected.
The last line of the stimuli file must be like this: 
999999999:FF 
fig, stimuli and logging options

See also 
Simulator options
Simulator modules