Add an initial serial GPIB (IEC) decoder.

2 files changed, 182 insertions, 0 deletions

diff --git a/decoders/iec/__init__.py b/decoders/iec/__init__.py
new file mode 100644
index 0000000..fa0d96f
--- /dev/null
+++ b/decoders/iec/__init__.py
@@ -0,0 +1,24 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2017 Marcus Comstedt <marcus@mc.pp.se>
+##
+## 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/>.
+##
+
+'''
+This protocol decoder can decode the Commodore serial IEEE-488 (IEC) protocol.
+'''
+
+from .pd import Decoder
diff --git a/decoders/iec/pd.py b/decoders/iec/pd.py
new file mode 100644
index 0000000..55b08ac
--- /dev/null
+++ b/decoders/iec/pd.py
@@ -0,0 +1,158 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2017 Marcus Comstedt <marcus@mc.pp.se>
+##
+## 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 = 2
+    id = 'iec'
+    name = 'IEC'
+    longname = 'Commodore bus'
+    desc = 'Commodore serial IEEE-488 (IEC) bus protocol.'
+    license = 'gplv2+'
+    inputs = ['logic']
+    outputs = ['gpib']
+    channels = (
+        {'id': 'data', 'name': 'DATA', 'desc': 'Data I/O'},
+        {'id': 'clk', 'name': 'CLK', 'desc': 'Clock'},
+        {'id': 'atn', 'name': 'ATN', 'desc': 'Attention'},
+    )
+    optional_channels = (
+        {'id': 'srq', 'name': 'SRQ', 'desc': 'Service request'},
+    )
+    annotations = (
+        ('items', 'Items'),
+        ('gpib', 'DAT/CMD'),
+        ('eoi', 'EOI'),
+    )
+    annotation_rows = (
+        ('bytes', 'Bytes', (0,)),
+        ('gpib', 'DAT/CMD', (1,)),
+        ('eoi', 'EOI', (2,)),
+    )
+
+    def __init__(self):
+        self.saved_ATN = False
+        self.saved_EOI = False
+        self.oldpins = None
+        self.ss_item = self.es_item = None
+        self.step = 0
+        self.bits = 0
+        self.numbits = 0
+
+    def start(self):
+        self.out_ann = self.register(srd.OUTPUT_ANN)
+
+    def putb(self, data):
+        self.put(self.ss_item, self.es_item, self.out_ann, data)
+
+    def handle_bits(self):
+        # Output the saved item.
+        dbyte = self.bits
+        dATN = self.saved_ATN
+        dEOI = self.saved_EOI
+        self.es_item = self.samplenum
+        self.putb([0, ['%02X' % dbyte]])
+
+        # Encode item byte to GPIB convention.
+        self.strgpib = ' '
+        if dATN: # ATN, decode commands.
+            # Note: Commands < 0x20 are not used on IEC bus.
+            if dbyte == 0x01: self.strgpib = 'GTL'
+            if dbyte == 0x04: self.strgpib = 'SDC'
+            if dbyte == 0x05: self.strgpib = 'PPC'
+            if dbyte == 0x08: self.strgpib = 'GET'
+            if dbyte == 0x09: self.strgpib = 'TCT'
+            if dbyte == 0x11: self.strgpib = 'LLO'
+            if dbyte == 0x14: self.strgpib = 'DCL'
+            if dbyte == 0x15: self.strgpib = 'PPU'
+            if dbyte == 0x18: self.strgpib = 'SPE'
+            if dbyte == 0x19: self.strgpib = 'SPD'
+
+            if dbyte == 0x3f: self.strgpib = 'UNL'
+            if dbyte == 0x5f: self.strgpib = 'UNT'
+            if dbyte > 0x1f and dbyte < 0x3f: # Address listener.
+                self.strgpib = 'L' + chr(dbyte + 0x10)
+            if dbyte > 0x3f and dbyte < 0x5f: # Address talker.
+                self.strgpib = 'T' + chr(dbyte - 0x10)
+            if dbyte > 0x5f and dbyte < 0x70: # Channel reopen.
+                self.strgpib = 'R' + chr(dbyte - 0x30)
+            if dbyte > 0xdf and dbyte < 0xf0: # Channel close.
+                self.strgpib = 'C' + chr(dbyte - 0xb0)
+            if dbyte > 0xef: # Channel open.
+                self.strgpib = 'O' + chr(dbyte - 0xc0)
+        else:
+            if dbyte > 0x1f and dbyte < 0x7f:
+                self.strgpib = chr(dbyte)
+            if dbyte == 0x0a:
+                self.strgpib = 'LF'
+            if dbyte == 0x0d:
+                self.strgpib = 'CR'
+
+        self.putb([1, [self.strgpib]])
+        self.strEOI = ' '
+        if dEOI:
+            self.strEOI = 'EOI'
+        self.putb([2, [self.strEOI]])
+
+    def decode(self, ss, es, data):
+        for (self.samplenum, pins) in data:
+
+            # Ignore identical samples early on (for performance reasons).
+            if self.oldpins == pins:
+                continue
+
+            if pins[2] == 0 and self.oldpins[2] == 1:
+                # Falling edge on ATN, reset step.
+                self.step = 0
+
+            if self.step == 0:
+                if pins[0] == 0 and pins[1] == 1:
+                    # Rising edge on CLK while DATA is low: Ready to send.
+                    self.step = 1
+            elif self.step == 1:
+                if pins[0] == 1 and pins[1] == 1:
+                    # Rising edge on DATA while CLK is high: Ready for data.
+                    self.ss_item = self.samplenum
+                    self.saved_ATN = not pins[2]
+                    self.saved_EOI = False
+                    self.bits = 0
+                    self.numbits = 0
+                    self.step = 2
+                elif pins[1] == 0:
+                    # CLK low again, transfer aborted.
+                    self.step = 0
+            elif self.step == 2:
+                if pins[0] == 0 and pins[1] == 1:
+                    # DATA goes low while CLK is still high, EOI confirmed.
+                    self.saved_EOI = True
+                elif pins[1] == 0:
+                    self.step = 3
+            elif self.step == 3:
+                if pins[1] == 1 and self.oldpins[1] == 0:
+                    # Rising edge on CLK; latch DATA.
+                    self.bits |= pins[0] << self.numbits
+                elif pins[1] == 0 and self.oldpins[1] == 1:
+                    # Falling edge on CLK; end of bit.
+                    self.numbits += 1
+                    if self.numbits == 8:
+                        self.handle_bits()
+                        self.step = 0
+
+            self.oldpins = pins