Add an initial GPIB decoder.

2 files changed, 214 insertions, 0 deletions

diff --git a/decoders/gpib/__init__.py b/decoders/gpib/__init__.py
new file mode 100644
index 0000000..3dae563
--- /dev/null
+++ b/decoders/gpib/__init__.py
@@ -0,0 +1,25 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2016 Rudolf Reuter <reuterru@arcor.de>
+##
+## 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 protocol decoder can decode the GPIB (IEEE-488) protocol.
+'''
+
+from .pd import Decoder
diff --git a/decoders/gpib/pd.py b/decoders/gpib/pd.py
new file mode 100644
index 0000000..0712966
--- /dev/null
+++ b/decoders/gpib/pd.py
@@ -0,0 +1,189 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2016 Rudolf Reuter <reuterru@arcor.de>
+##
+## 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 = 'gpib'
+    name = 'GPIB'
+    longname = 'General Purpose Interface Bus'
+    desc = 'IEEE-488 GPIB / HPIB protocol.'
+    license = 'gplv2+'
+    inputs = ['logic']
+    outputs = ['gpib']
+    channels = (
+        {'id': 'dio1' , 'name': 'DIO1', 'desc': 'Data I/O bit 1'},
+        {'id': 'dio2' , 'name': 'DIO2', 'desc': 'Data I/O bit 2'},
+        {'id': 'dio3' , 'name': 'DIO3', 'desc': 'Data I/O bit 3'},
+        {'id': 'dio4' , 'name': 'DIO4', 'desc': 'Data I/O bit 4'},
+        {'id': 'dio5' , 'name': 'DIO5', 'desc': 'Data I/O bit 5'},
+        {'id': 'dio6' , 'name': 'DIO6', 'desc': 'Data I/O bit 6'},
+        {'id': 'dio7' , 'name': 'DIO7', 'desc': 'Data I/O bit 7'},
+        {'id': 'dio8' , 'name': 'DIO8', 'desc': 'Data I/O bit 8'},
+        {'id': 'eoi', 'name': 'EOI', 'desc': 'End or identify'},
+        {'id': 'dav', 'name': 'DAV', 'desc': 'Data valid'},
+        {'id': 'nrfd', 'name': 'NRFD', 'desc': 'Not ready for data'},
+        {'id': 'ndac', 'name': 'NDAC', 'desc': 'Not data accepted'},
+        {'id': 'ifc', 'name': 'IFC', 'desc': 'Interface clear'},
+        {'id': 'srq', 'name': 'SRQ', 'desc': 'Service request'},
+        {'id': 'atn', 'name': 'ATN', 'desc': 'Attention'},
+        {'id': 'ren', 'name': 'REN', 'desc': 'Remote enable'},
+    )
+    options = (
+        {'id': 'sample_total', 'desc': 'Total number of samples', 'default': 0},
+    )
+    annotations = (
+        ('items', 'Items'),
+        ('gpib', 'DAT/CMD'),
+        ('eoi', 'EOI'),
+    )
+    annotation_rows = (
+        ('bytes', 'Bytes', (0,)),
+        ('gpib', 'DAT/CMD', (1,)),
+        ('eoi', 'EOI', (2,)),
+    )
+
+    def __init__(self):
+        self.olddav = None
+        self.items = []
+        self.itemcount = 0
+        self.saved_item = None
+        self.saved_ATN = False
+        self.saved_EOI = False
+        self.samplenum = 0
+        self.oldpins = None
+        self.ss_item = self.es_item = None
+        self.first = True
+
+    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, datapins):
+        dbyte = 0x20
+        dATN = False
+        item2 = False
+        dEOI = False
+        item3 = False
+        # If this is the first item in a word, save its sample number.
+        if self.itemcount == 0:
+            self.ss_word = self.samplenum
+
+        # Get the bits for this item.
+        item = 0
+        for i in range(8):
+            item |= datapins[i] << i
+
+        item = item ^ 0xff # Invert data byte.
+        self.items.append(item)
+        self.itemcount += 1
+
+        if datapins[14] == 0:
+            item2 = True
+        if datapins[8] == 0:
+            item3 = True
+
+        if self.first:
+            # Save the start sample and item for later (no output yet).
+            self.ss_item = self.samplenum
+            self.first = False
+            self.saved_item = item
+            self.saved_ATN = item2
+            self.saved_EOI = item3
+        else:
+            # Output the saved item.
+            dbyte = self.saved_item
+            dATN = self.saved_ATN
+            dEOI = self.saved_EOI
+            self.es_item = self.samplenum
+            self.putb([0, ['%02X' % self.saved_item]])
+
+            # Encode item byte to GPIB convention.
+            self.strgpib = ' '
+            if dATN: # ATN, decode commands.
+                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)
+            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]])
+
+            self.ss_item = self.samplenum
+            self.saved_item = item
+            self.saved_ATN = item2
+            self.saved_EOI = item3
+
+        if self.itemcount < 16:
+            return
+
+        self.itemcount, self.items = 0, []
+
+    def find_falling_dav_edge(self, dav, datapins):
+        # Ignore sample if the DAV pin hasn't changed.
+        if dav == self.olddav:
+            return
+        self.olddav = dav
+        # Sample on falling DAV edge.
+        if dav == 1:
+            return
+
+        # Found the correct DAV edge, now get the bits.
+        self.handle_bits(datapins)
+
+    def decode(self, ss, es, data):
+        lsn = self.options['sample_total']
+
+        for (self.samplenum, pins) in data:
+            if lsn > 0:
+                if (lsn - self.samplenum) == 1: # Show the last data word.
+                    self.handle_bits(pins)
+
+            # Ignore identical samples early on (for performance reasons).
+            if self.oldpins == pins:
+                continue
+            self.oldpins = pins
+
+            self.find_falling_dav_edge(pins[9], pins)