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#!/usr/bin/env python
speeds = (9600, 19200, 38400, 57600, 115200, 230400)
master_clk = 100e6
wb_clk = master_clk / 2
def divisor(speed):
div0 = wb_clk // (speed * 16)
div1 = div0 + 1
actual0 = actual_speed(div0)
actual1 = actual_speed(div1)
if abs(actual0 - speed) < abs(actual1 - speed):
return div0
else:
return div1
def actual_speed(divisor):
return (wb_clk // divisor) / 16
def doit(speed):
div = divisor(speed)
actual = actual_speed(div)
rel_error = (actual - speed) / speed
print "target: %6d divisor: %6d actual: %11.4f %6.3f%%" % (speed, div, actual, rel_error*100)
def main():
print "wb_clk = %f" % (wb_clk,)
for s in speeds:
doit(s)
if __name__ == '__main__':
main()
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