Par Port Speed

Howdy! I was thinking about Parallel Port speed and seem to recall
hearing some wise and august person say the speed depends mostly on the
bus, not on the CPU. I have been playing with BASIC and the following
code will give you a rough idea of your upper speed limit. On a 486/33
DOS box, that turns out to be ~11 ipm. YMMWV (your mileage WILL vary).

Rick Dulas

CLS
INPUT "Number of Micro Steps/Full Step: ", Micro%
IF Micro% = 0 THEN
Micro% = 1
END IF
IPM:
INPUT "Number of Steps/Inch of travel:[no commas] ", StepsInch%
SELECT CASE StepsInch%
CASE IS <= 0
PRINT "Please put in the positive, whole number of steps to move
the machine 1 inch."
GOSUB IPM
CASE 1 TO 10000
StepsInch% = StepsInch%
CASE IS > 10000
PRINT "Check your decimal place."
GOSUB IPM
END SELECT
INPUT "Number of Iterations: "; k%
InchFactor% = StepsInch% * Micro%
AvgCPS& = 0
FOR i = 1 TO k%
StartTime = TIMER
n = 0
WHILE (TIMER - StartTime) <= 1
OUT &H378, 1
OUT &H378, 3
n = n + 1
WEND
AvgCPS& = (AvgCPS& + n)
'PRINT "cycles/second: "; n; "inches/min: "; ((n - 1) / InchFactor%)
* 60
'PRINT AvgCPS& / i
NEXT i
PRINT "Average cycles/second: "; AvgCPS& / (i - 1); " Average IPM:
"; ((AvgCPS& / (i - 1)) / InchFactor%) * 60



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