Last active
August 29, 2015 14:16
-
-
Save cltnschlosser/e747efae07a76e117e02 to your computer and use it in GitHub Desktop.
Provide a frequency and this will provide the arduino code needed to create a timer interrupt
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
def OCR(freq, prescaler): | |
return (16000000 / (prescaler * freq)) - 1 | |
def HZ(ocr, prescaler): | |
return (16000000 / (prescaler * (ocr+1))) | |
def checkBit(data, bit): | |
return bool(data & (1<<bit)) | |
def checkTimerValid(li): | |
for li1 in li: | |
for li2 in li: | |
if type(li2[1]) is not str: | |
return True | |
def twoDec(val): | |
return "{0:.2f}".format(val) | |
def stringifyTop(timer, freq, actual): | |
return "\n\ | |
void setup()\n\ | |
{\n\ | |
cli();\n\ | |
\n\ | |
//set timer"+str(timer)+" interrupt at "+str(freq)+"Hz ("+twoDec(actual)+")\n\ | |
TCCR"+str(timer)+"A = 0;\n\ | |
TCCR"+str(timer)+"B = 0;\n\ | |
TCNT"+str(timer)+" = 0;\n\ | |
\n" | |
def stringifyBottom(timer): | |
return "\n\ | |
sei();\n\ | |
}\n\ | |
\n\ | |
ISR(TIMER"+str(timer)+"_COMPA_vect){\n\ | |
//Interrupt Code Here\n\ | |
}" | |
def stringifyOCR(timer, n): | |
return " OCR"+ str(timer)+"A = "+str(n)+";\n" | |
def stringifyPrescaler(timer, index): | |
line = " TCCR"+str(timer)+"B |=" | |
for bit in [2,1,0]: | |
if checkBit(index+1, bit): | |
line+=" (1 << CS"+str(timer)+str(bit)+") |" | |
return line[:-2]+";\n" | |
def stringifyCTC(timer): | |
return " TCCR"+str(timer)+("A" if timer!=1 else "B")+" |= (1 << WGM"+str(timer)+("1" if timer!=1 else "2")+");\n" | |
def stringifyEnable(timer): | |
return " TIMSK"+str(timer)+" |= (1 << OCIE"+str(timer)+"A);\n" | |
#main | |
prescalers = [1,8,64,256,1024] | |
prescalers2 = [1,8,32,64] | |
output = [[],[],[]]#timer0,timer1,timer2 inner [prescaler, OCR] | |
desired_freq = int(input("Desired Frequency? (Hz): ")) | |
for timer in range(3): | |
maxOCR = 255 | |
if timer == 1: | |
maxOCR = 65535 | |
for prescaler in (prescalers if timer!=2 else prescalers2): | |
ocr = OCR(desired_freq, prescaler) | |
acc = 0; | |
if ocr > maxOCR or ocr < 1: | |
acc = "" | |
ocr = "" | |
else: | |
acc = twoDec(100-abs(ocr-int(round(ocr)))/ocr*100) | |
ocr = int(round(ocr)) | |
output[timer].append([prescaler, ocr, acc]) | |
head = ["index", "prescaler", "OCR", "accuracy"] | |
row_format = "{!s:>6}{!s:>11}{!s:>7}{!s:>11}" | |
for i in range(len(output)): | |
timer = output[i] | |
print() | |
print(row_format.format("","timer"+str(i),"","")) | |
print(row_format.format(*head)) | |
for i in range(len(timer)): | |
print(row_format.format(i,*timer[i])) | |
timer = int(input("Choose a timer (0,1,2): ")) | |
while not (timer >= 0 and timer <= 2 and checkTimerValid(output[timer])): | |
timer = int(input("Not an option. Choose a timer (0,1,2): ")) | |
pscale = int(input("Choose a prescaler index: ")) | |
while not (pscale >= 0 and pscale <= (4 if timer!=2 else 3) and type(output[timer][pscale][1]) is not str): | |
pscale = int(input("Not an option. Choose a prescaler index: ")) | |
print(stringifyTop(timer,desired_freq,HZ(output[timer][pscale][1], output[timer][pscale][0]))+\ | |
stringifyOCR(timer, output[timer][pscale][1])+\ | |
stringifyCTC(timer)+\ | |
stringifyPrescaler(timer,pscale)+\ | |
stringifyEnable(timer)+\ | |
stringifyBottom(timer)) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Very useful! Thanks