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diff code_part1/OSTC_code_asm_part1/spbrgselect.inc @ 0:96a35aeda5f2

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Initial setup
author heinrichsweikamp
date Tue, 12 Jan 2010 15:05:59 +0100
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/code_part1/OSTC_code_asm_part1/spbrgselect.inc	Tue Jan 12 15:05:59 2010 +0100
@@ -0,0 +1,33 @@
+RoundResult SET 0				; Rounding function.  RoundResult = Round(aa/bb)
+Round	macro aa,bb
+	LOCAL rr = aa/bb
+	LOCAL d1 = aa - rr*bb
+	LOCAL d2 = (rr+1)*bb - aa
+RoundResult = rr
+	if d1 >= d2
+RoundResult++
+	endif
+	endm
+
+AbsResult SET 0
+Abs		macro nr
+	if nr>=0
+AbsResult = nr
+	else
+AbsResult = -nr
+	endif
+	endm
+		
+	Round xtal,(16*baud)
+spbrg_value EQU RoundResult-1
+
+	Round xtal,(16*(spbrg_value+1))
+baud_real EQU RoundResult
+	Abs(baud_real-baud)
+errpercent EQU AbsResult*100/baud
+	if errpercent > 4
+		ERROR big error in baudrate: #v(errpercent)%
+	endif
+	if errpercent >= 2
+		messg baudrate not exact: #v(errpercent)%
+	endif
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