##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2017 Kevin Redon <kingkevin@cuvoodoo.info>
## Copyright (C) 2017 Soeren Apel <soeren@apelpie.net>
##
## 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, see <http://www.gnu.org/licenses/>.
##
import sigrokdecode as srd
# Dictionary of FUNCTION commands and their names.
commands_2432 = {
0x0f: 'Write scratchpad',
0xaa: 'Read scratchpad',
0x55: 'Copy scratchpad',
0xf0: 'Read memory',
0x5a: 'Load first secret',
0x33: 'Compute next secret',
0xa5: 'Read authenticated page',
}
commands_2433 = {
0x0f: 'Write scratchpad',
0xaa: 'Read scratchpad',
0x55: 'Copy scratchpad',
0xf0: 'Read memory',
}
# Maxim DS243x family code, present at the end of the ROM code.
family_codes = {
0x33: ('DS2432', commands_2432),
0x23: ('DS2433', commands_2433),
}
# Calculate the CRC-16 checksum.
# Initial value: 0x0000, xor-in: 0x0000, polynom 0x8005, xor-out: 0xffff.
def crc16(byte_array):
reverse = 0xa001 # Use the reverse polynom to make algo simpler.
crc = 0x0000 # Initial value.
# Reverse CRC calculation.
for byte in byte_array:
for bit in range(8):
if (byte ^ crc) & 1:
crc = (crc >> 1) ^ reverse
else:
crc >>= 1
byte >>= 1
crc ^= 0xffff # Invert CRC.
return crc
class Decoder(srd.Decoder):
api_version = 3
id = 'ds243x'
name = 'DS243x'
longname = 'Maxim DS2432/3'
desc = 'Maxim DS243x series 1-Wire EEPROM protocol.'
license = 'gplv2+'
inputs = ['onewire_network']
outputs = []
tags = ['IC', 'Memory']
annotations = (
('text', 'Text'),
)
binary = (
('mem_read', 'Data read from memory'),
)
def __init__(self):
self.reset()
def reset(self):
# Bytes for function command.
self.bytes = []
self.family_code = None
self.family = ''
self.commands = commands_2432 # Use max command set until we know better.
def start(self):
self.out_ann = self.register(srd.OUTPUT_ANN)
self.out_binary = self.register(srd.OUTPUT_BINARY)
def putx(self, data):
self.put(self.ss, self.es, self.out_ann, data)
def decode(self, ss, es, data):
code, val = data
if code == 'RESET/PRESENCE':
self.ss, self.es = ss, es
self.putx([0, ['Reset/presence: %s'
% ('true' if val else 'false')]])
self.bytes = []
elif code == 'ROM':
self.ss, self.es = ss, es
self.family_code = val & 0xff
s = None
if self.family_code in family_codes:
self.family, self.commands = family_codes[val & 0xff]
s = 'is 0x%02x, %s detected' % (self.family_code, self.family)
else:
s = '0x%02x unknown' % (self.family_code)
self.putx([0, ['ROM: 0x%016x (%s)' % (val, 'family code ' + s),
'ROM: 0x%016x (%s)' % (val, self.family)]])
self.bytes = []
elif code == 'DATA':
self.bytes.append(val)
if 1 == len(self.bytes):
self.ss, self.es = ss, es
if val not in self.commands:
self.putx([0, ['Unrecognized command: 0x%02x' % val]])
else:
self.putx([0, ['Function command: %s (0x%02x)'
% (self.commands[val], val)]])
elif 0x0f == self.bytes[0]: # Write scratchpad
if 2 == len(self.bytes):
self.ss = ss
elif 3 == len(self.bytes):
self.es = es
self.putx([0, ['Target address: 0x%04x'
% ((self.bytes[2] << 8) + self.bytes[1])]])
elif 4 == len(self.bytes):
self.ss = ss
elif 11 == len(self.bytes):
self.es = es
self.putx([0, ['Data: ' + (','.join(format(n, '#04x')
for n in self.bytes[3:11]))]])
elif 12 == len(self.bytes):
self.ss = ss
elif 13 == len(self.bytes):
self.es = es
self.putx([0, ['CRC: '
+ ('ok' if crc16(self.bytes[0:11]) == (self.bytes[11]
+ (self.bytes[12] << 8)) else 'error')]])
elif 0xaa == self.bytes[0]: # Read scratchpad
if 2 == len(self.bytes):
self.ss = ss
elif 3 == len(self.bytes):
self.es = es
self.putx([0, ['Target address: 0x%04x'
% ((self.bytes[2] << 8) + self.bytes[1])]])
elif 4 == len(self.bytes):
self.ss, self.es = ss, es
self.putx([0, ['Data status (E/S): 0x%02x'
% (self.bytes[3])]])
elif 5 == len(self.bytes):
self.ss = ss
elif 12 == len(self.bytes):
self.es = es
self.putx([0, ['Data: ' + (','.join(format(n, '#04x')
for n in self.bytes[4:12]))]])
elif 13 == len(self.bytes):
self.ss = ss
elif 14 == len(self.bytes):
self.es = es
self.putx([0, ['CRC: '
+ ('ok' if crc16(self.bytes[0:12]) == (self.bytes[12]
+ (self.bytes[13] << 8)) else 'error')]])
elif 0x5a == self.bytes[0]: # Load first secret
if 2 == len(self.bytes):
self.ss = ss
elif 4 == len(self.bytes):
self.es = es
self.putx([0, ['Authorization pattern (TA1, TA2, E/S): '
+ (','.join(format(n, '#04x')
for n in self.bytes[1:4]))]])
elif 4 < len(self.bytes):
self.ss, self.es = ss, es
if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
self.putx([0, ['End of operation']])
elif 0x33 == self.bytes[0]: # Compute next secret
if 2 == len(self.bytes):
self.ss = ss
elif 3 == len(self.bytes):
self.es = es
self.putx([0, ['Target address: 0x%04x'
% ((self.bytes[2] << 8) + self.bytes[1])]])
elif 3 < len(self.bytes):
self.ss, self.es = ss, es
if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
self.putx([0, ['End of operation']])
elif 0x55 == self.bytes[0]: # Copy scratchpad
if 2 == len(self.bytes):
self.ss = ss
elif 4 == len(self.bytes):
self.es = es
self.putx([0, ['Authorization pattern (TA1, TA2, E/S): '
+ (','.join(format(n, '#04x')
for n in self.bytes[1:4]))]])
elif 5 == len(self.bytes):
self.ss = ss
elif 24 == len(self.bytes):
self.es = es
mac = ','.join(format(n, '#04x') for n in self.bytes[4:24])
self.putx([0, ['Message authentication code: ' + mac,
'MAC: ' + mac]])
elif 24 < len(self.bytes):
self.ss, self.es = ss, es
if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
self.putx([0, ['Operation succeeded']])
elif (0 == self.bytes[-1]):
self.putx([0, ['Operation failed']])
elif 0xa5 == self.bytes[0]: # Read authenticated page
if 2 == len(self.bytes):
self.ss = ss
elif 3 == len(self.bytes):
self.es = es
self.putx([0, ['Target address: 0x%04x'
% ((self.bytes[2] << 8) + self.bytes[1])]])
elif 4 == len(self.bytes):
self.ss = ss
elif 35 == len(self.bytes):
self.es = es
self.putx([0, ['Data: ' + (','.join(format(n, '#04x')
for n in self.bytes[3:35]))]])
elif 36 == len(self.bytes):
self.ss, self.es = ss, es
self.putx([0, ['Padding: '
+ ('ok' if 0xff == self.bytes[-1] else 'error')]])
elif 37 == len(self.bytes):
self.ss = ss
elif 38 == len(self.bytes):
self.es = es
self.putx([0, ['CRC: '
+ ('ok' if crc16(self.bytes[0:36]) == (self.bytes[36]
+ (self.bytes[37] << 8)) else 'error')]])
elif 39 == len(self.bytes):
self.ss = ss
elif 58 == len(self.bytes):
self.es = es
mac = ','.join(format(n, '#04x') for n in self.bytes[38:58])
self.putx([0, ['Message authentication code: ' + mac,
'MAC: ' + mac]])
elif 59 == len(self.bytes):
self.ss = ss
elif 60 == len(self.bytes):
self.es = es
self.putx([0, ['MAC CRC: '
+ ('ok' if crc16(self.bytes[38:58]) == (self.bytes[58]
+ (self.bytes[59] << 8)) else 'error')]])
elif 60 < len(self.bytes):
self.ss, self.es = ss, es
if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
self.putx([0, ['Operation completed']])
elif 0xf0 == self.bytes[0]: # Read memory
if 2 == len(self.bytes):
self.ss = ss
elif 3 == len(self.bytes):
self.es = es
self.putx([0, ['Target address: 0x%04x'
% ((self.bytes[2] << 8) + self.bytes[1])]])
elif 3 < len(self.bytes):
self.ss, self.es = ss, es
self.putx([0, ['Data: 0x%02x' % (self.bytes[-1])]])
bdata = self.bytes[-1].to_bytes(1, byteorder='big')
self.put(ss, es, self.out_binary, [0, bdata])