For anyone interested, I finally broke down and built/posted a M.S. Excel 2000 Spreadsheet (Yes I know its microsoft but thats the office suite I have access to) that can be used to calculate timer preload values (in decimal and hex) to achieve specific user input sampling rates based off a manual Crystal frequency input (For both 16 & 8 bit). Will also calculate UBRR register values for specific baud rates given the same maunal Crystal frequency input and the associated baud error rates. Will calculate the Crystal frequency required for a 0% baud error rate for a user input desired baud rate.
NOTE: This calculators require hex conversion functions found in the Excel Analysis TookPak.
If you modify Cells and and view #NAME? in the answer cells you do not have the Analysis ToolPak available. If this function is not available, run the Setup program (M.S. Office or Excel) to install the Analysis ToolPak. After you install the Analysis ToolPak, you must enable it by using the Add-Ins command on the Tools menu.
It can be found under the Lab Resources Link on this web page
comments would be appreciated.
Erick L. Oberstar
Mechatronics Lab Manager/Engineer
University of Wisconsin - Madison
1513 University Ave.
Madison, WI 53706