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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>
## Copyright (C) 2014 alberink <alberink@stampfini.org>
##
## 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
class Decoder(srd.Decoder):
api_version = 3
id = 'tca6408a'
name = 'TI TCA6408A'
longname = 'Texas Instruments TCA6408A'
desc = 'Texas Instruments TCA6408A 8-bit I²C I/O expander.'
license = 'gplv2+'
inputs = ['i2c']
outputs = []
tags = ['Embedded/industrial', 'IC']
annotations = (
('register', 'Register type'),
('value', 'Register value'),
('warnings', 'Warning messages'),
)
annotation_rows = (
('regs', 'Registers', (0, 1)),
('warnings', 'Warnings', (2,)),
)
def __init__(self):
self.reset()
def reset(self):
self.state = 'IDLE'
self.chip = -1
def start(self):
self.out_ann = self.register(srd.OUTPUT_ANN)
def putx(self, data):
self.put(self.ss, self.es, self.out_ann, data)
def handle_reg_0x00(self, b):
self.putx([1, ['State of inputs: %02X' % b]])
def handle_reg_0x01(self, b):
self.putx([1, ['Outputs set: %02X' % b ]])
def handle_reg_0x02(self, b):
self.putx([1, ['Polarity inverted: %02X' % b]])
def handle_reg_0x03(self, b):
self.putx([1, ['Configuration: %02X' % b]])
def handle_write_reg(self, b):
if b == 0:
self.putx([0, ['Input port', 'In', 'I']])
elif b == 1:
self.putx([0, ['Output port', 'Out', 'O']])
elif b == 2:
self.putx([0, ['Polarity inversion register', 'Pol', 'P']])
elif b == 3:
self.putx([0, ['Configuration register', 'Conf', 'C']])
def check_correct_chip(self, addr):
if addr not in (0x20, 0x21):
self.putx([2, ['Warning: I²C slave 0x%02X not a TCA6408A '
'compatible chip.' % addr]])
self.state = 'IDLE'
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'
elif self.state == 'GET SLAVE ADDR':
self.chip = databyte
self.state = 'GET REG ADDR'
elif self.state == 'GET REG ADDR':
# Wait for a data write (master selects the slave register).
if cmd in ('ADDRESS READ', 'ADDRESS WRITE'):
self.check_correct_chip(databyte)
if cmd != 'DATA WRITE':
return
self.reg = databyte
self.handle_write_reg(self.reg)
self.state = 'WRITE IO REGS'
elif self.state == 'WRITE IO REGS':
# If we see a Repeated Start here, the master wants to read.
if cmd == 'START REPEAT':
self.state = 'READ IO 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)
elif cmd == 'STOP':
self.state = 'IDLE'
self.chip = -1
elif self.state == 'READ IO REGS':
# Wait for an address read operation.
if cmd == 'ADDRESS READ':
self.state = 'READ IO REGS2'
self.chip = databyte
return
elif self.state == 'READ IO REGS2':
if cmd == 'DATA READ':
handle_reg = getattr(self, 'handle_reg_0x%02x' % self.reg)
handle_reg(databyte)
elif cmd == 'STOP':
self.state = 'IDLE'
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