##
## This file is part of the sigrok project.
##
## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
##
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program; if not, write to the Free Software
## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
##
# JTAG protocol decoder
import sigrokdecode as srd
class Decoder(srd.Decoder):
api_version = 1
id = 'jtag'
name = 'JTAG'
longname = 'Joint Test Action Group (IEEE 1149.1)'
desc = 'Protocol for testing, debugging, and flashing ICs.'
license = 'gplv2+'
inputs = ['logic']
outputs = ['jtag']
probes = [
{'id': 'tdi', 'name': 'TDI', 'desc': 'Test data input'},
{'id': 'tdo', 'name': 'TDO', 'desc': 'Test data output'},
{'id': 'tck', 'name': 'TCK', 'desc': 'Test clock'},
{'id': 'tms', 'name': 'TMS', 'desc': 'Test mode select'},
]
optional_probes = [
{'id': 'trst', 'name': 'TRST#', 'desc': 'Test reset'},
{'id': 'srst', 'name': 'SRST#', 'desc': 'System reset'},
{'id': 'rtck', 'name': 'RTCK', 'desc': 'Return clock signal'},
]
options = {}
annotations = [
['Text', 'Human-readable text'],
]
def __init__(self, **kwargs):
# self.state = 'TEST-LOGIC-RESET'
self.state = 'RUN-TEST/IDLE'
self.oldstate = None
self.oldpins = (-1, -1, -1, -1)
self.oldtck = -1
self.bits_tdi = []
self.bits_tdo = []
def start(self, metadata):
self.out_proto = self.add(srd.OUTPUT_PROTO, 'jtag')
self.out_ann = self.add(srd.OUTPUT_ANN, 'jtag')
def report(self):
pass
def advance_state_machine(self, tms):
self.oldstate = self.state
# Intro "tree"
if self.state == 'TEST-LOGIC-RESET':
self.state = 'TEST-LOGIC-RESET' if (tms) else 'RUN-TEST/IDLE'
elif self.state == 'RUN-TEST/IDLE':
self.state = 'SELECT-DR-SCAN' if (tms) else 'RUN-TEST/IDLE'
# DR "tree"
elif self.state == 'SELECT-DR-SCAN':
self.state = 'SELECT-IR-SCAN' if (tms) else 'CAPTURE-DR'
elif self.state == 'CAPTURE-DR':
self.state = 'EXIT1-DR' if (tms) else 'SHIFT-DR'
elif self.state == 'SHIFT-DR':
self.state = 'EXIT1-DR' if (tms) else 'SHIFT-DR'
elif self.state == 'EXIT1-DR':
self.state = 'UPDATE-DR' if (tms) else 'PAUSE-DR'
elif self.state == 'PAUSE-DR':
self.state = 'EXIT2-DR' if (tms) else 'PAUSE-DR'
elif self.state == 'EXIT2-DR':
self.state = 'UPDATE-DR' if (tms) else 'SHIFT-DR'
elif self.state == 'UPDATE-DR':
self.state = 'SELECT-DR-SCAN' if (tms) else 'RUN-TEST/IDLE'
# IR "tree"
elif self.state == 'SELECT-IR-SCAN':
self.state = 'TEST-LOGIC-RESET' if (tms) else 'CAPTURE-IR'
elif self.state == 'CAPTURE-IR':
self.state = 'EXIT1-IR' if (tms) else 'SHIFT-IR'
elif self.state == 'SHIFT-IR':
self.state = 'EXIT1-IR' if (tms) else 'SHIFT-IR'
elif self.state == 'EXIT1-IR':
self.state = 'UPDATE-IR' if (tms) else 'PAUSE-IR'
elif self.state == 'PAUSE-IR':
self.state = 'EXIT2-IR' if (tms) else 'PAUSE-IR'
elif self.state == 'EXIT2-IR':
self.state = 'UPDATE-IR' if (tms) else 'SHIFT-IR'
elif self.state == 'UPDATE-IR':
self.state = 'SELECT-DR-SCAN' if (tms) else 'RUN-TEST/IDLE'
else:
raise Exception('Invalid state: %s' % self.state)
def handle_rising_tck_edge(self, tdi, tdo, tck, tms):
# Rising TCK edges always advance the state machine.
self.advance_state_machine(tms)
# Output the state we just switched to.
self.put(self.ss, self.es, self.out_ann,
[0, ['New state: %s' % self.state]])
self.put(self.ss, self.es, self.out_proto,
['NEW STATE', self.state])
# If we went from SHIFT-IR to SHIFT-IR, or SHIFT-DR to SHIFT-DR,
# collect the current TDI/TDO values (upon rising TCK edge).
if self.state.startswith('SHIFT-') and self.oldstate == self.state:
self.bits_tdi.insert(0, tdi)
self.bits_tdo.insert(0, tdo)
# TODO: ANN/PROTO output.
# self.put(self.ss, self.es, self.out_ann,
# [0, ['TDI add: ' + str(tdi)]])
# self.put(self.ss, self.es, self.out_ann,
# [0, ['TDO add: ' + str(tdo)]])
# Output all TDI/TDO bits if we just switched from SHIFT-* to EXIT1-*.
if self.oldstate.startswith('SHIFT-') and \
self.state.startswith('EXIT1-'):
t = self.state[-2:] + ' TDI'
b = ''.join(map(str, self.bits_tdi))
h = ' (0x%x' % int('0b' + b, 2) + ')'
s = t + ': ' + b + h + ', ' + str(len(self.bits_tdi)) + ' bits'
self.put(self.ss, self.es, self.out_ann, [0, [s]])
self.put(self.ss, self.es, self.out_proto, [t, b])
self.bits_tdi = []
t = self.state[-2:] + ' TDO'
b = ''.join(map(str, self.bits_tdo))
h = ' (0x%x' % int('0b' + b, 2) + ')'
s = t + ': ' + b + h + ', ' + str(len(self.bits_tdo)) + ' bits'
self.put(self.ss, self.es, self.out_ann, [0, [s]])
self.put(self.ss, self.es, self.out_proto, [t, b])
self.bits_tdo = []
def decode(self, ss, es, data):
for (samplenum, pins) in data:
# If none of the pins changed, there's nothing to do.
if self.oldpins == pins:
continue
# Store current pin values for the next round.
self.oldpins = pins
# Get individual pin values into local variables.
# Unused probes will have a value of > 1.
(tdi, tdo, tck, tms, trst, srst, rtck) = pins
# We only care about TCK edges (either rising or falling).
if (self.oldtck == tck):
continue
# Store start/end sample for later usage.
self.ss, self.es = ss, es
# self.put(self.ss, self.es, self.out_ann,
# [0, ['tdi:%s, tdo:%s, tck:%s, tms:%s' \
# % (tdi, tdo, tck, tms)]])
if (self.oldtck == 0 and tck == 1):
self.handle_rising_tck_edge(tdi, tdo, tck, tms)
self.oldtck = tck