Add decoder for TCA6408A I2C I/O expanders.

2 files changed, 157 insertions, 0 deletions

diff --git a/decoders/tca6408a/__init__.py b/decoders/tca6408a/__init__.py
new file mode 100644
index 0000000..9982d58
--- /dev/null
+++ b/decoders/tca6408a/__init__.py
@@ -0,0 +1,26 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## 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, write to the Free Software
+## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+##
+
+'''
+This decoder stacks on top of the 'i2c' PD and decodes the Texas Instruments
+TCA6408A 8-bit I²C I/O expander protocol.
+'''
+
+from .pd import *
diff --git a/decoders/tca6408a/pd.py b/decoders/tca6408a/pd.py
new file mode 100644
index 0000000..443a298
--- /dev/null
+++ b/decoders/tca6408a/pd.py
@@ -0,0 +1,131 @@
+##
+## 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, write to the Free Software
+## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+##
+
+import sigrokdecode as srd
+
+class Decoder(srd.Decoder):
+    api_version = 2
+    id = 'tca6408a'
+    name = 'TCA6408A'
+    longname = 'TI TCA6408A'
+    desc = 'Texas Instruments TCA6408A 8-bit I²C I/O expander.'
+    license = 'gplv2+'
+    inputs = ['i2c']
+    outputs = ['tca6408a']
+    annotations = (
+        ('register', 'Register type'),
+        ('value', 'Register value'),
+        ('warnings', 'Warning messages'),
+    )
+    annotation_rows = (
+        ('regs', 'Registers', (0, 1)),
+        ('warnings', 'Warnings', (2,)),
+    )
+
+    def __init__(self, **kwargs):
+        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'
+            self.block_start_sample = ss
+        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'
+