def detect_register_size(self):
# Freely inpired from UrJTAG
# Need to contact authors, or to replace this code to comply with
# the GPL license (GPL vs. LGPL with Python is a bit fuzzy for me)
if not self._engine._sm.state_of("shift"):
raise JtagError("Invalid state: %s" % self._engine._sm.state())
if self._engine._sm.state_of("capture"):
bs = BitSequence(False)
self._engine._ctrl.write_tms(bs)
self._engine._sm.handle_events(bs)
MAX_REG_LEN = 1024
PATTERN_LEN = 8
stuck = None
for length in range(1, MAX_REG_LEN):
print_("Testing for length %d" % length)
if length > 5:
return
zero = BitSequence(length=length)
inj = BitSequence(length=length + PATTERN_LEN)
inj.inc()
ok = False
for p in range(1, 1 << PATTERN_LEN):
ok = False
self._engine.write(zero, False)
rcv = self._engine.shift_register(inj)
try:
tdo = rcv.invariant()
except ValueError:
tdo = None
if stuck is None:
stuck = tdo
if stuck != tdo:
stuck = None
rcv >>= length
if rcv == inj:
ok = True
else:
break
inj.inc()
if ok:
print_("Register detected length: %d" % length)
return length
if stuck is not None:
raise JtagError("TDO seems to be stuck")
raise JtagError("Unable to detect register length")
def detect_register_size(self):
# Freely inpired from UrJTAG
# Need to contact authors, or to replace this code to comply with
# the GPL license (GPL vs. LGPL with Python is a bit fuzzy for me)
if not self._engine._sm.state_of('shift'):
raise JtagError("Invalid state: %s" % self._engine._sm.state())
if self._engine._sm.state_of('capture'):
bs = BitSequence(False)
self._engine._ctrl.write_tms(bs)
self._engine._sm.handle_events(bs)
MAX_REG_LEN = 1024
PATTERN_LEN = 8
stuck = None
for length in range(1, MAX_REG_LEN):
print_("Testing for length %d" % length)
if length > 5:
return
zero = BitSequence(length=length)
inj = BitSequence(length=length + PATTERN_LEN)
inj.inc()
ok = False
for p in range(1, 1 << PATTERN_LEN):
ok = False
self._engine.write(zero, False)
rcv = self._engine.shift_register(inj)
try:
tdo = rcv.invariant()
except ValueError:
tdo = None
if stuck is None:
stuck = tdo
if stuck != tdo:
stuck = None
rcv >>= length
if rcv == inj:
ok = True
else:
break
inj.inc()
if ok:
print_("Register detected length: %d" % length)
return length
if stuck is not None:
raise JtagError('TDO seems to be stuck')
raise JtagError('Unable to detect register length')
