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##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
## Copyright (C) 2013 Matt Ranostay <mranostay@gmail.com>
##
## 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
##
# Dallas DS1307 RTC protocol decoder
import sigrokdecode as srd
days_of_week = [
'Sunday',
'Monday',
'Tuesday',
'Wednesday',
'Thursday',
'Friday',
'Saturday',
]
# Return the specified BCD number (max. 8 bits) as integer.
def bcd2int(b):
return (b & 0x0f) + ((b >> 4) * 10)
class Decoder(srd.Decoder):
api_version = 1
id = 'ds1307'
name = 'DS1307'
longname = 'Dallas DS1307'
desc = 'Realtime clock module protocol.'
license = 'gplv2+'
inputs = ['i2c']
outputs = ['ds1307']
probes = []
optional_probes = []
options = {}
annotations = [
['Text', 'Human-readable text'],
]
def __init__(self, **kwargs):
self.state = 'IDLE'
self.hours = -1
self.minutes = -1
self.seconds = -1
self.days = -1
self.date = -1
self.months = -1
self.years = -1
def start(self):
self.out_ann = self.add(srd.OUTPUT_ANN, 'ds1307')
def report(self):
pass
def putx(self, data):
self.put(self.ss, self.es, self.out_ann, data)
def handle_reg_0x00(self, b): # Seconds
self.seconds = bcd2int(b & 0x7f)
self.putx([0, ['Seconds: %d' % self.seconds]])
def handle_reg_0x01(self, b): # Minutes
self.minutes = bcd2int(b & 0x7f)
self.putx([0, ['Minutes: %d' % self.minutes]])
def handle_reg_0x02(self, b): # Hours
self.hours = bcd2int(b & 0x3f)
self.putx([0, ['Hours: %d' % self.hours]])
def handle_reg_0x03(self, b): # Day of week
self.days = bcd2int(b & 0x7)
self.putx([0, ['Day of Week: %s' % days_of_week[self.days - 1]]])
def handle_reg_0x04(self, b): # Date
self.date = bcd2int(b & 0x3f)
self.putx([0, ['Days: %d' % self.date]])
def handle_reg_0x05(self, b): # Month
self.months = bcd2int(b & 0x1f)
self.putx([0, ['Months: %d' % self.months]])
def handle_reg_0x06(self, b): # Year
self.years = bcd2int(b & 0xff) + 2000;
self.putx([0, ['Years: %d' % self.years]])
def handle_reg_0x07(self, b): # Control Register
pass
def decode(self, ss, es, data):
cmd, databyte = data
# Store the start/end samples of this I2C packet.
self.ss, self.es = ss, es
# State machine.
if self.state == 'IDLE':
# Wait for an I2C START condition.
if cmd != 'START':
return
self.state = 'GET SLAVE ADDR'
self.block_start_sample = ss
elif self.state == 'GET SLAVE ADDR':
# Wait for an address write operation.
# TODO: We should only handle packets to the RTC slave (0x68).
if cmd != 'ADDRESS WRITE':
return
self.state = 'GET REG ADDR'
elif self.state == 'GET REG ADDR':
# Wait for a data write (master selects the slave register).
if cmd != 'DATA WRITE':
return
self.reg = databyte
self.state = 'WRITE RTC REGS'
elif self.state == 'WRITE RTC REGS':
# If we see a Repeated Start here, it's probably an RTC read.
if cmd == 'START REPEAT':
self.state = 'READ RTC REGS'
return
# Otherwise: Get data bytes until a STOP condition occurs.
if cmd == 'DATA WRITE':
handle_reg = getattr(self, 'handle_reg_0x%02x' % self.reg)
handle_reg(databyte)
self.reg += 1
# TODO: Check for NACK!
elif cmd == 'STOP':
# TODO: Handle read/write of only parts of these items.
d = '%s, %02d.%02d.%02d %02d:%02d:%02d' % (
days_of_week[self.days - 1], self.date, self.months,
self.years, self.hours, self.minutes, self.seconds)
self.put(self.block_start_sample, es, self.out_ann,
[0, ['Written date/time: %s' % d]])
self.state = 'IDLE'
else:
pass # TODO
elif self.state == 'READ RTC REGS':
# Wait for an address read operation.
# TODO: We should only handle packets to the RTC slave (0x68).
if cmd == 'ADDRESS READ':
self.state = 'READ RTC REGS2'
return
else:
pass # TODO
elif self.state == 'READ RTC REGS2':
if cmd == 'DATA READ':
handle_reg = getattr(self, 'handle_reg_0x%02x' % self.reg)
handle_reg(databyte)
self.reg += 1
# TODO: Check for NACK!
elif cmd == 'STOP':
d = '%s, %02d.%02d.%02d %02d:%02d:%02d' % (
days_of_week[self.days - 1], self.date, self.months,
self.years, self.hours, self.minutes, self.seconds)
self.put(self.block_start_sample, es, self.out_ann,
[0, ['Read date/time: %s' % d]])
self.state = 'IDLE'
else:
pass # TODO?
else:
raise Exception('Invalid state: %s' % self.state)
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