mirror of
git://projects.qi-hardware.com/ben-wpan.git
synced 2024-11-04 23:14:06 +02:00
atusb/fw3/an/: USB debugging scripts
This commit is contained in:
parent
c1dc00ee44
commit
f4d299d22b
25
atusb/fw3/an/README
Normal file
25
atusb/fw3/an/README
Normal file
@ -0,0 +1,25 @@
|
||||
workflow:
|
||||
|
||||
- connect zprobe (note: it currently inverts because it didn't have any
|
||||
other chips around. this may change later.)
|
||||
|
||||
- capture the USB signals at an interesting moment with a sample rate of
|
||||
50 MSa/s
|
||||
|
||||
- zoom into the frame(s) of interest
|
||||
|
||||
- download the data with
|
||||
./get.py
|
||||
|
||||
- decode with
|
||||
./dec.py
|
||||
|
||||
For manual decoding, set the coders to D+ and D- (we need D- for SE0
|
||||
and SE1 detection), then click on a rising clock edge left of the
|
||||
packet and move the cursor to the right.
|
||||
|
||||
- if there are problems with the clock, the analog signal and digital
|
||||
signals derived from it can be examined after running dec.py with
|
||||
./plot
|
||||
|
||||
(Note that the digital zprobe hides any analog anomalies.)
|
127
atusb/fw3/an/dec.py
Executable file
127
atusb/fw3/an/dec.py
Executable file
@ -0,0 +1,127 @@
|
||||
#!/usr/bin/python
|
||||
|
||||
from tmc.wave import *
|
||||
from tmc.dxplore import dxplore
|
||||
from tmc.decode import d_usb_stream
|
||||
|
||||
|
||||
#
|
||||
# Clock recovery: we assume that each change in the wave is triggered by a
|
||||
# clock edge. We know the clock's nominal period and resynchronize on each
|
||||
# edge. Additionally, we can obtain a list of times when a timing violation
|
||||
# has occurred.
|
||||
#
|
||||
# Note that the timing violations logic doesn't make much sense in its present
|
||||
# form, since it mainly measures noise (particularly if we're digitizing slow
|
||||
# edges) and not clock drift.
|
||||
#
|
||||
# A more useful metric would be accumulated error from some point of reference
|
||||
# or at least the timing of same edges, to eliminate (generally harmless) time
|
||||
# offsets introduced by digitizing.
|
||||
#
|
||||
# So it would probably make more sense for "recover" not to check for timing
|
||||
# violations at all, and leave this to more specialized functions.
|
||||
#
|
||||
def recover(self, period, min = None, max = None, t0 = None):
|
||||
if t0 is None:
|
||||
t0 = self.data[0]
|
||||
v = not self.initial
|
||||
res = []
|
||||
violations = []
|
||||
for t in self.data:
|
||||
v = not v
|
||||
if t <= t0:
|
||||
continue
|
||||
n = 0
|
||||
while t0 < t-period/2:
|
||||
res.append(t0)
|
||||
t0 += period
|
||||
n += 1
|
||||
if min is not None:
|
||||
if t0-t > n*min:
|
||||
violations.append(t)
|
||||
if max is not None:
|
||||
if t-t0 > n*max:
|
||||
violations.append(t)
|
||||
t0 = t
|
||||
return res, violations
|
||||
|
||||
|
||||
#
|
||||
# Load the analog waves saved by get.py
|
||||
#
|
||||
wv = waves()
|
||||
wv.load("_wv")
|
||||
|
||||
#
|
||||
# Digitize the waves and save the result.
|
||||
#
|
||||
dp = wv[0].digitize(1.5, 1.8)
|
||||
dm = wv[1].digitize(1.5, 1.8)
|
||||
wv = waves(dp, dm, dp-dm)
|
||||
wv.save("_dig")
|
||||
|
||||
#
|
||||
# Also record the differential signal.
|
||||
#
|
||||
wd = wv[1]-wv[0]
|
||||
dd = wd.digitize(-0.5, 0.5)
|
||||
wd.save("_diff")
|
||||
|
||||
#
|
||||
# Run clock recovery on D+/D-. We only need one, but check both to be sure.
|
||||
#
|
||||
#p = 1/1.5e6
|
||||
p = 1/12e6
|
||||
dp_t, viol = recover(dp, p, p*0.9, p*1.1)
|
||||
print viol
|
||||
dm_t, viol = recover(dm, p, p*.9, p*1.1, t0 = dp.data[0])
|
||||
print viol
|
||||
|
||||
#
|
||||
# Shift the clock by half a period, add a few periods to get steady state and
|
||||
# SE0s (if any), and then sample the data lines.
|
||||
#
|
||||
clk = map(lambda t: t+p/2, dp_t)
|
||||
clk.extend((clk[-1]+p, clk[-1]+2*p, clk[-1]+3*p))
|
||||
dp_bv = dp.get(clk)
|
||||
dm_bv = dm.get(clk)
|
||||
|
||||
#
|
||||
# Save a wave with the recovered clock to make it easier to find the bits in
|
||||
# analog graphs.
|
||||
#
|
||||
dd.data = dp_t;
|
||||
dd.save("_clk")
|
||||
|
||||
#
|
||||
# For decoding, we need a fake bit clock. We generate it by doubling each data
|
||||
# bit and generating a L->H transition during this bit.
|
||||
#
|
||||
dpd = []
|
||||
dmd = []
|
||||
dck = []
|
||||
|
||||
# err, silly, seems that we've mixed up D+ and D- all over the place :-)
|
||||
print d_usb_stream(dm_bv[:], dp_bv[:])
|
||||
|
||||
for v in dp_bv:
|
||||
dpd.append(v)
|
||||
dpd.append(v)
|
||||
dck.append(0)
|
||||
dck.append(1)
|
||||
|
||||
for v in dm_bv:
|
||||
dmd.append(v)
|
||||
dmd.append(v)
|
||||
|
||||
#
|
||||
# Display the reconstructed digital signal. Note that the absolute time is only
|
||||
# correct at the beginning and that relative time is only accurate over
|
||||
# intervals in which no significant clock resynchronization has occurred.
|
||||
#
|
||||
# In fact, dxplore should probably have an option to either turn off time
|
||||
# entirely or to display a user-provided time axis. The latter may be a bit
|
||||
# tricky to implement.
|
||||
#
|
||||
dxplore((dmd, dpd, dck), 0, p/2, labels = ("D+", "D-", "CLK"))
|
31
atusb/fw3/an/get.py
Executable file
31
atusb/fw3/an/get.py
Executable file
@ -0,0 +1,31 @@
|
||||
#!/usr/bin/python
|
||||
|
||||
from tmc.scope import rigol_ds1000c
|
||||
|
||||
#-800, +1600
|
||||
s = rigol_ds1000c()
|
||||
#s.debug = False
|
||||
|
||||
pos = s.hor.pos
|
||||
scale = s.hor.scale
|
||||
t0 = pos-scale*s.div_hor/2
|
||||
t1 = pos+scale*s.div_hor/2
|
||||
print t0, t1
|
||||
|
||||
#zoom = 10
|
||||
#step = scale/s.samples_per_div/zoom
|
||||
#print step
|
||||
step = 4e-9
|
||||
step = 2e-9
|
||||
|
||||
w = s.wave((s.ch[0], s.ch[1]), start = t0, end = t1, step = step)
|
||||
w[0] = 3.3-w[0]
|
||||
w[1] = 3.3-w[1]
|
||||
|
||||
s.hor.pos = pos
|
||||
s.hor.scale = scale
|
||||
|
||||
w[0].label = "D+";
|
||||
w[1].label = "D-";
|
||||
|
||||
w.save("_wv")
|
12
atusb/fw3/an/plot
Executable file
12
atusb/fw3/an/plot
Executable file
@ -0,0 +1,12 @@
|
||||
#!/bin/sh
|
||||
#
|
||||
# Plot output of "dec"
|
||||
#
|
||||
gnuplot -persist <<EOF
|
||||
set style data lines
|
||||
plot "_wv" using 1:(\$2-4), \
|
||||
"_dig" using 1:(\$2*3.3-4) lw 2, \
|
||||
"_wv" using 1:3, \
|
||||
"_dig" using 1:(\$3*3.3) lw 2, \
|
||||
"_clk" using 1:(\$2+1) lt 7
|
||||
EOF
|
Loading…
Reference in New Issue
Block a user