stoneship.org.uk Git - bootloader/blob - mybootload.X/spbrgselect.inc

   1 RoundResult SET 0                               ; Rounding function.  RoundResult = Round(aa/bb)\r
   2 Round   macro aa,bb\r
   3         LOCAL rr = aa/bb\r
   4         LOCAL d1 = aa - rr*bb\r
   5         LOCAL d2 = (rr+1)*bb - aa\r
   6 RoundResult = rr\r
   7         if d1 >= d2\r
   8 RoundResult++\r
   9         endif\r
  10         endm\r
  11 \r
  12 AbsResult SET 0\r
  13 Abs             macro nr\r
  14         if nr>=0\r
  15 AbsResult = nr\r
  16         else\r
  17 AbsResult = -nr\r
  18         endif\r
  19         endm\r
  20                 \r
  21         Round xtal,(16*baud)\r
  22 spbrg_value EQU RoundResult-1\r
  23 \r
  24         Round xtal,(16*(spbrg_value+1))\r
  25 baud_real EQU RoundResult\r
  26         Abs(baud_real-baud)\r
  27 errpercent EQU AbsResult*100/baud\r
  28         if errpercent > 4\r
  29                 ERROR big error in baudrate: #v(errpercent)%\r
  30         endif\r
  31         if errpercent >= 2\r
  32                 messg baudrate not exact: #v(errpercent)%\r
  33         endif