I created something like this in Excel. It writes binary data (based on the content of the spreadsheet) to a file, which then in turn gets included in a project that is written to some flash chip using the programmer. All is called from a VBA macro inside the document.
Press Alt+F11 to create a new VBA module in the file, go from cell to cell, convert the data, write it out to a file and this should do it.
The interesting parts of the code look like this:
filenum = FreeFile
If Dir(file) <> "" Then
SetAttr file, vbNormal
Kill (file)
End If
Open file For Binary Access Write As #filenum
Seek #filenum, 1
For a = LBound(data) To UBound(data)
by = CByte(data(a))
Put #filenum, a + 1, by
Next a
Close #filenum
where file is the filename with path, data an array containing the bytes.