Decoder for Xicor X2444M, nonvolatile static RAM.

2 files changed, 134 insertions, 0 deletions

diff --git a/decoders/x2444m/__init__.py b/decoders/x2444m/__init__.py
new file mode 100644
index 0000000..70d2146
--- /dev/null
+++ b/decoders/x2444m/__init__.py
@@ -0,0 +1,25 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2018 Stefan Petersen <spe@ciellt.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 decoder stacks on top of the 'spi' PD and decodes the Xicor X2444M/P
+nonvolatile static RAM protocol.
+'''
+
+from .pd import Decoder
diff --git a/decoders/x2444m/pd.py b/decoders/x2444m/pd.py
new file mode 100644
index 0000000..e061d62
--- /dev/null
+++ b/decoders/x2444m/pd.py
@@ -0,0 +1,109 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2018 Stefan Petersen <spe@ciellt.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 re
+import sigrokdecode as srd
+
+registers = {
+    0x80: ['WRDS',  lambda _: ''],
+    0x81: ['STO',   lambda _: ''],
+    0x82: ['SLEEP', lambda _: ''],
+    0x83: ['WRITE', lambda v: '0x%x' % v],
+    0x84: ['WREN',  lambda _: ''],
+    0x85: ['RCL',   lambda _: ''],
+    0x86: ['READ',  lambda v: '0x%x' % v],
+    0x87: ['READ',  lambda v: '0x%x' % v],
+}
+
+ann_write, ann_read = range(2)
+
+class Decoder(srd.Decoder):
+    api_version = 3
+    id = 'x2444m'
+    name = 'X2444M/P'
+    longname = 'Xicor X2444M/P'
+    desc = 'Xicor X2444M/P nonvolatile static RAM protocol.'
+    license = 'gplv2+'
+    inputs = ['spi']
+    outputs = ['x2444m']
+    annotations = (
+        ('write', 'Commands and data written to the device'),
+        ('read', 'Data read from the device'),
+    )
+    annotation_rows = (
+        ('data', 'Data', (ann_write, ann_read)),
+    )
+
+    def __init__(self):
+        self.reset()
+
+    def reset(self):
+        pass
+
+    def start(self):
+        self.out_ann = self.register(srd.OUTPUT_ANN)
+        self.cs_start = 0
+        self.cs_asserted = False
+        self.cmd_digit = 0
+
+    def putreadwrite(self, ss, es, reg, addr, value):
+        self.put(ss, es, self.out_ann,
+                 [ann_write, ['%s: %s => 0x%4.4x' % (reg, addr, value)]])
+
+    def putcmd(self, ss, es, reg):
+        self.put(ss, es, self.out_ann, [ann_write, ['%s' % reg]])
+
+    def decode(self, ss, es, data):
+        ptype, mosi, miso = data
+
+        if ptype == 'DATA':
+            if not self.cs_asserted:
+                return
+
+            if self.cmd_digit == 0:
+                self.addr = mosi
+                self.addr_start = ss
+            elif self.cmd_digit > 0:
+                self.read_value = (self.read_value << 8) + miso
+                self.write_value = (self.write_value << 8) + mosi
+            self.cmd_digit += 1
+        elif ptype == 'CS-CHANGE':
+            self.cs_asserted = (miso == 1)
+            # When not asserted, CS has just changed from asserted to deasserted.
+            if not self.cs_asserted:
+                # Only one digit, simple command. Else read/write.
+                if self.cmd_digit == 1:
+                    name, decoder = registers[self.addr & 0x87]
+                    self.putcmd(self.addr_start, es, name)
+                elif self.cmd_digit > 1:
+                    name, decoder = registers[self.addr & 0x87]
+                    if name == 'READ':
+                        value = self.read_value
+                    elif name == 'WRITE':
+                        value = self.write_value
+                    else:
+                        value = 0
+                    self.putreadwrite(self.addr_start, es, name,
+                                      decoder((self.addr >> 3) & 0x0f), value)
+
+            if self.cs_asserted:
+                self.cs_start = ss
+                self.cmd_digit = 0
+                self.read_value = 0
+                self.write_value = 0