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March 22, 2023 15:38
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Simulate serial RS232 data to use as a PWL file for LTspice
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#!/usr/bin/python | |
data = "asdfg" | |
bps = 115200 | |
num_databits=8 | |
parity = 'n' | |
num_stopbits = 1 | |
lvl_0 = 3.3 | |
lvl_1 = 0.0 | |
if type(data) is str: | |
data = [data] | |
out = oldout = 0 | |
time = 0.0 | |
timestep = 1.0/bps | |
risetime = falltime = timestep / 20.0 | |
idletime = timestep * (num_databits + 3) | |
def do_timestep(output, step): | |
global time | |
global out, oldout | |
global lvl_0, lvl_1 | |
out = output | |
time_diff = 0 | |
if oldout!= out: | |
if oldout > out: | |
# fall | |
time_diff = falltime | |
else: | |
# rise | |
time_diff = risetime | |
lvl = (lvl_0 if oldout == 0 else lvl_1) | |
print ("{0:g} {1:g}".format(time, lvl)) | |
lvl = (lvl_0 if out == 0 else lvl_1) | |
print ("{0:g} {1:g}".format((time + time_diff), lvl)) | |
oldout = out | |
time += step | |
return time | |
do_timestep(0,0) | |
# idle | |
do_timestep(0, idletime) | |
for sentence in data: | |
# start bit | |
out = 1 | |
do_timestep(out, timestep) | |
for char in sentence: | |
# print("# {}").format(char); | |
par = 0 | |
for bit in range(0, num_databits): | |
out = (ord(char) >> bit) & 1 | |
par = bool(parity) ^ bool(out) | |
do_timestep(out, timestep) | |
if parity == 'e': | |
# even parity | |
out = par | |
elif parity == 'o': | |
# odd parity | |
out = ~par | |
do_timestep(out, timestep) | |
# stop bits | |
out = 0 | |
do_timestep(out, (timestep * num_stopbits)) | |
# idle | |
out = 0 | |
do_timestep(out, idletime) |
thx for this suggestion
Script was otherwise very useful, thanks!
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Your code has bugs in it.
Line 37: print ("{0:g} {1:g}".format(time, lvl));
Line 39: print ("{0:g} {1:g}".format((time + time_diff), lvl));
The brackets are wrong.
Also, in Python, the lines do not need ";" on the end :)