Improved PS/2 decoder, added stacked mouse decoder

decoders/ps2/__init__.py

@@ -2,6 +2,7 @@
 ## This file is part of the libsigrokdecode project.
 ##
 ## Copyright (C) 2016 Daniel Schulte <[email protected]>
+## Copyright (C) 2023 Marshal Horn <[email protected]>
 ##
 ## 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
@@ -18,9 +19,11 @@
 ##
 
 '''
-This protocol decoder can decode PS/2 device -> host communication.
+This protocol decoder can decode PS/2 device -> host communication \
+and host -> device communication.
 
-Host -> device communication is currently not supported.
+To interpret the data, please stack the appropriate keyboard or mouse \
+decoder
 '''
 
 from .pd import Decoder

decoders/ps2/pd.py

@@ -2,6 +2,7 @@
 ## This file is part of the libsigrokdecode project.
 ##
 ## Copyright (C) 2016 Daniel Schulte <[email protected]>
+## Copyright (C) 2023 Marshal Horn <[email protected]>
 ##
 ## 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
@@ -18,22 +19,33 @@
 ##
 
 import sigrokdecode as srd
-from collections import namedtuple
 
 class Ann:
-    BIT, START, STOP, PARITY_OK, PARITY_ERR, DATA, WORD = range(7)
+    BIT, START, WORD, PARITY_OK, PARITY_ERR, STOP, ACK, NACK, HREQ, HSTART, HWORD, HPARITY_OK, HPARITY_ERR, HSTOP = range(14)
+
+class Bit:
+    def __init__(self, val, ss, es):
+        self.val = val
+        self.ss = ss
+        self.es = es
+
+class Ps2Packet:
+    def __init__(self, val, host=False, pok=False, ack=False):
+        self.val  = val     #byte value
+        self.host = host    #Host transmissions
+        self.pok  = pok     #Parity ok
+        self.ack  = ack     #Acknowlege ok for host transmission.
 
-Bit = namedtuple('Bit', 'val ss es')
 
 class Decoder(srd.Decoder):
     api_version = 3
     id = 'ps2'
     name = 'PS/2'
     longname = 'PS/2'
-    desc = 'PS/2 keyboard/mouse interface.'
+    desc = 'PS/2 packet interface used by PC keyboards and mice'
     license = 'gplv2+'
     inputs = ['logic']
-    outputs = []
+    outputs = ['ps2']
     tags = ['PC']
     channels = (
         {'id': 'clk', 'name': 'Clock', 'desc': 'Clock line'},
@@ -42,85 +54,131 @@ class Decoder(srd.Decoder):
     annotations = (
         ('bit', 'Bit'),
         ('start-bit', 'Start bit'),
-        ('stop-bit', 'Stop bit'),
+        ('word', 'Word'),
         ('parity-ok', 'Parity OK bit'),
         ('parity-err', 'Parity error bit'),
-        ('data-bit', 'Data bit'),
+        ('stop-bit', 'Stop bit'),
+        ('ack', 'Acknowledge'),
+        ('nack', 'Not Acknowledge'),
+        ('req', 'Host request to send'),
+        ('start-bit', 'Start bit'),
         ('word', 'Word'),
+        ('parity-ok', 'Parity OK bit'),
+        ('parity-err', 'Parity error bit'),
+        ('stop-bit', 'Stop bit'),
     )
     annotation_rows = (
         ('bits', 'Bits', (0,)),
-        ('fields', 'Fields', (1, 2, 3, 4, 5, 6)),
+        ('fields', 'Device', (1,2,3,4,5,6,7,)),
+        ('host', 'Host', (8,9,10,11,12,13)),
     )
 
     def __init__(self):
         self.reset()
+        self.min_clk_hz = 9e3 #Minimum clock rate for PS/2 is 10kHz, but I want to be lenient
 
     def reset(self):
         self.bits = []
         self.bitcount = 0
 
     def start(self):
         self.out_ann = self.register(srd.OUTPUT_ANN)
-
-    def putb(self, bit, ann_idx):
-        b = self.bits[bit]
-        self.put(b.ss, b.es, self.out_ann, [ann_idx, [str(b.val)]])
+        self.out_py = self.register(srd.OUTPUT_PYTHON)
+
+    def metadata(self,key,value):
+        if key == srd.SRD_CONF_SAMPLERATE:
+            self.samplerate = value
+
+    def get_bits(self, n, edge:'r'):
+        _, dat = self.wait([{0:edge},{1:'l'}]) #No timeout for start bit
+        if not self.matched[1]:
+            return #No start bit
+        self.bits.append(Bit(dat, self.samplenum, self.samplenum+self.max_period))
+        if not self.matched[0]:
+            self.wait({0:'f'}) #Wait for clock edge from device
+        for i in range(1,n):
+            _, dat = self.wait([{0:edge},{'skip':self.max_period}])
+            if not self.matched[0]:
+                break #Timed out
+            self.bits.append(Bit(dat, self.samplenum, self.samplenum+self.max_period))
+            #Fix the ending period
+            self.bits[i-1].es = self.samplenum
+        if len(self.bits) == n:
+            self.wait([{0:'r'},{'skip':self.max_period}])
+            self.bits[-1].es = self.samplenum
+        self.bitcount = len(self.bits)
 
     def putx(self, bit, ann):
         self.put(self.bits[bit].ss, self.bits[bit].es, self.out_ann, ann)
 
-    def handle_bits(self, datapin):
-        # Ignore non start condition bits (useful during keyboard init).
-        if self.bitcount == 0 and datapin == 1:
-            return
-
-        # Store individual bits and their start/end samplenumbers.
-        self.bits.append(Bit(datapin, self.samplenum, self.samplenum))
-
-        # Fix up end sample numbers of the bits.
-        if self.bitcount > 0:
-            b = self.bits[self.bitcount - 1]
-            self.bits[self.bitcount - 1] = Bit(b.val, b.ss, self.samplenum)
-        if self.bitcount == 11:
-            self.bitwidth = self.bits[1].es - self.bits[2].es
-            b = self.bits[-1]
-            self.bits[-1] = Bit(b.val, b.ss, b.es + self.bitwidth)
-
-        # Find all 11 bits. Start + 8 data + odd parity + stop.
-        if self.bitcount < 11:
-            self.bitcount += 1
-            return
-
-        # Extract data word.
-        word = 0
-        for i in range(8):
-            word |= (self.bits[i + 1].val << i)
+    def handle_bits(self, host=False):
+        packet = None
+        if self.bitcount > 8:
+            # Annotate individual bits
+            for b in self.bits:
+                self.put(b.ss, b.es, self.out_ann, [Ann.BIT, [str(b.val)]])
+            # Annotate start bit
+            self.putx(0, [Ann.HSTART if host else Ann.START, ['Start bit', 'Start', 'S']])
+            # Annotate the data word
+            word = 0 
+            for i in range(8):
+                word |= (self.bits[i + 1].val << i)
+            self.put(self.bits[1].ss, self.bits[8].es, self.out_ann, 
+                [Ann.HWORD if host else Ann.WORD, 
+                ['Data: %02x' % word, 'D: %02x' % word, '%02x' % word]])
+            packet = Ps2Packet(val = word, host = host)
 
         # Calculate parity.
-        parity_ok = (bin(word).count('1') + self.bits[9].val) % 2 == 1
-
-        # Emit annotations.
-        for i in range(11):
-            self.putb(i, Ann.BIT)
-        self.putx(0, [Ann.START, ['Start bit', 'Start', 'S']])
-        self.put(self.bits[1].ss, self.bits[8].es, self.out_ann, [Ann.WORD,
-                 ['Data: %02x' % word, 'D: %02x' % word, '%02x' % word]])
-        if parity_ok:
-            self.putx(9, [Ann.PARITY_OK, ['Parity OK', 'Par OK', 'P']])
-        else:
-            self.putx(9, [Ann.PARITY_ERR, ['Parity error', 'Par err', 'PE']])
-        self.putx(10, [Ann.STOP, ['Stop bit', 'Stop', 'St', 'T']])
+        if self.bitcount > 9:
+            parity_ok = 0
+            for bit in self.bits[1:10]:
+                parity_ok ^= bit.val
+            if bool(parity_ok):
+                self.putx(9, [Ann.HPARITY_OK if host else Ann.PARITY_OK, ['Parity OK', 'Par OK', 'P']])
+                packet.pok = True #Defaults to false in case packet was interrupted
+            else:
+                self.putx(9, [Ann.HPARITY_ERR if host else Ann.PARITY_ERR, ['Parity error', 'Par err', 'PE']])
+
+        # Annotate stop bit
+        if self.bitcount > 10:
+            self.putx(10, [Ann.HSTOP if host  else Ann.STOP, ['Stop bit', 'Stop', 'St', 'T']])
+        # Annotate ACK
+        if host and self.bitcount > 11:
+            if self.bits[11].val == 0:
+                self.putx(11, [Ann.ACK, ['Acknowledge', 'Ack', 'A']])
+            else:
+                self.putx(11, [Ann.NACK, ['Not Acknowledge', 'Nack', 'N']])
+            packet.ack = not bool(self.bits[11].val)
+
+        if(packet):
+            self.put(self.bits[0].ss, self.bits[-1].ss, self.out_py,packet)
+        self.reset()
 
-        self.bits, self.bitcount = [], 0
 
     def decode(self):
+        if self.samplerate:
+            self.max_period = int(self.samplerate / self.min_clk_hz)+1
+        else:
+            raise SamplerateError("Cannot decode without samplerate")
         while True:
-            # Sample data bits on the falling clock edge (assume the device
-            # is the transmitter). Expect the data byte transmission to end
-            # at the rising clock edge. Cope with the absence of host activity.
-            _, data_pin = self.wait({0: 'f'})
-            self.handle_bits(data_pin)
-            if self.bitcount == 1 + 8 + 1 + 1:
-                _, data_pin = self.wait({0: 'r'})
-                self.handle_bits(data_pin)
+            # Falling edge of data indicates start condition
+            # Clock held for 100us indicates host "request to send"
+            self.wait([{1: 'f'},{0:'l'}])
+            ss = self.samplenum
+            host = self.matched[1]
+            if host:
+                # Make sure the clock is held low for at least 100 microseconds before data is pulled down
+                self.wait([{0:'h'},{'skip': self.max_period},{1:'l'}])
+                if self.matched[0]:
+                    continue #Probably the trailing edge of a transfer
+                elif self.matched[2]: #Probably a bus error
+                    self.wait({1:'h'}) #Wait for data to be released
+                    continue
+                # Host emits bits on rising clk edge
+                self.get_bits(12, 'r')
+                if self.bitcount > 0:
+                    self.put(ss,self.bits[0].ss,self.out_ann, [Ann.HREQ,['Host RTS', 'HRTS', 'H']])
+            else:
+                # Client emits data on falling edge
+                self.get_bits(11, 'f')
+            self.handle_bits(host=host)

decoders/ps2_keyboard/__init__.py

@@ -0,0 +1,25 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2023 Marshal Horn <[email protected]>
+##
+## 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 PS/2 keyboard commands.
+It should be stacked on the PS/2 packet decoder.
+'''
+
+from .pd import Decoder

decoders/ps2_keyboard/pd.py

@@ -0,0 +1,93 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2023 Marshal Horn <[email protected]>
+##
+## 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
+from .sc import key_decode
+
+class Ps2Packet:
+    def __init__(self, val, host=False, pok=False, ack=False):
+        self.val  = val     #byte value
+        self.host = host    #Host transmissions
+        self.pok  = pok     #Parity ok
+        self.ack  = ack     #Acknowlege ok for host transmission.
+
+class Ann:
+    PRESS,RELEASE,ACK = range(3)
+
+class Decoder(srd.Decoder):
+    api_version = 3
+    id = 'ps2_keyboard'
+    name = 'PS/2 Keyboard'
+    longname = 'PS/2 Keyboard'
+    desc = 'PS/2 keyboard interface.'
+    license = 'gplv2+'
+    inputs = ['ps2']
+    outputs = []
+    tags = ['PC']
+    binary = (
+        ('Keys', 'Key presses'),
+    )
+    annotations = (
+        ('Press', 'Key pressed'),
+        ('Release', 'Key released'),
+        ('Ack', 'Acknowledge'),
+    )
+    annotation_rows = (
+        ('keys', 'key presses and releases',(0,1,2)),
+    )
+
+    def __init__(self):
+        self.reset()
+
+    def reset(self):
+        self.sw = 0 #for switch statement
+        self.ann = Ann.PRESS #defualt to keypress
+        self.extended = False
+
+    def start(self):
+        self.out_binary = self.register(srd.OUTPUT_BINARY)
+        self.out_ann = self.register(srd.OUTPUT_ANN)
+
+    def decode(self,startsample,endsample,data):
+        if data.host:
+            # Ignore host commands or interrupted keycodes
+            self.reset()
+            return
+        if self.sw < 1:
+            self.ss = startsample
+            self.sw = 1
+        if self.sw < 2:
+            if data.val == 0xF0: #Break code
+                self.ann = Ann.RELEASE
+                return
+            elif data.val == 0xE0: #Extended character
+                self.extended = True
+                return
+            elif data.val == 0xFA: #Acknowledge code
+                c = ['Acknowledge','ACK']
+                self.ann = Ann.ACK
+                self.sw = 4
+        if self.sw < 3:
+            c = key_decode(data.val, self.extended)
+
+        self.put(self.ss,endsample,self.out_ann,[self.ann,c])
+        if self.ann == Ann.PRESS:
+            self.put(self.ss,endsample,self.out_binary,[0,c[-1].encode('UTF-8')])
+        self.reset()
+