X-Git-Url: https://sigrok.org/gitweb/?p=libsigrokdecode.git;a=blobdiff_plain;f=scripts%2Fi2c.py;h=f0e168849cca00d68b13356ab3de6b4e3cf38c45;hp=f7022f5c3fce29397e66ed8acf98442a2523f3c5;hb=15167916e6e9d88b2b421c3ce2a80f7b29f25ce0;hpb=0588ed702725edbb5ed37ceb63fced93a5e68251

diff --git a/scripts/i2c.py b/scripts/i2c.py
index f7022f5..f0e1688 100644
--- a/scripts/i2c.py
+++ b/scripts/i2c.py
@@ -41,13 +41,13 @@
 # Repeated START condition (Sr): same as S
 # STOP condition (P): SDA = rising, SCL = high
 #
-# All data bytes on SDA are extactly 8 bits long (transmitted MSB-first).
+# All data bytes on SDA are exactly 8 bits long (transmitted MSB-first).
 # Each byte has to be followed by a 9th ACK/NACK bit. If that bit is low,
 # that indicates an ACK, if it's high that indicates a NACK.
 #
 # After the first START condition, a master sends the device address of the
 # slave it wants to talk to. Slave addresses are 7 bits long (MSB-first).
-# After those 7 bits a data direction bit is sent. If the bit is low that
+# After those 7 bits, a data direction bit is sent. If the bit is low that
 # indicates a WRITE operation, if it's high that indicates a READ operation.
 #
 # Later an optional 10bit slave addressing scheme was added.
@@ -65,44 +65,108 @@
 # TODO: Implement support for inverting SDA/SCL levels (0->1 and 1->0).
 # TODO: Implement support for detecting various bus errors.
 
-# TODO: Return two buffers, one with structured data for the GUI to parse
-#       and display, and one with human-readable ASCII output.
+#
+# I2C output format:
+#
+# The output consists of a (Python) list of I2C "packets", each of which
+# has an (implicit) index number (its index in the list).
+# Each packet consists of a Python dict with certain key/value pairs.
+#
+# TODO: Make this a list later instead of a dict?
+#
+# 'type': (string)
+#   - 'S' (START condition)
+#   - 'Sr' (Repeated START)
+#   - 'AR' (Address, read)
+#   - 'AW' (Address, write)
+#   - 'DR' (Data, read)
+#   - 'DW' (Data, write)
+#   - 'P' (STOP condition)
+# 'range': (tuple of 2 integers, the min/max samplenumber of this range)
+#   - (min, max)
+#   - min/max can also be identical.
+# 'data': (actual data as integer ???) TODO: This can be very variable...
+# 'ann': (string; additional annotations / comments)
+#
+# Example output:
+# [{'type': 'S',  'range': (150, 160), 'data': None, 'ann': 'Foobar'},
+#  {'type': 'AW', 'range': (200, 300), 'data': 0x50, 'ann': 'Slave 4'},
+#  {'type': 'DW', 'range': (310, 370), 'data': 0x00, 'ann': 'Init cmd'},
+#  {'type': 'AR', 'range': (500, 560), 'data': 0x50, 'ann': 'Get stat'},
+#  {'type': 'DR', 'range': (580, 640), 'data': 0xfe, 'ann': 'OK'},
+#  {'type': 'P',  'range': (650, 660), 'data': None, 'ann': None}]
+#
+# Possible other events:
+#   - Error event in case protocol looks broken:
+#     [{'type': 'ERROR', 'range': (min, max),
+#	'data': TODO, 'ann': 'This is not a Microchip 24XX64 EEPROM'},
+#     [{'type': 'ERROR', 'range': (min, max),
+#	'data': TODO, 'ann': 'TODO'},
+#   - TODO: Make list of possible errors accessible as metadata?
+#
+# TODO: I2C address of slaves.
+# TODO: Handle multiple different I2C devices on same bus
+#       -> we need to decode multiple protocols at the same time.
+# TODO: range: Always contiguous? Splitted ranges? Multiple per event?
+#
+
+#
+# I2C input format:
+#
+# signals:
+# [[id, channel, description], ...] # TODO
+#
+# Example:
+# {'id': 'SCL', 'ch': 5, 'desc': 'Serial clock line'}
+# {'id': 'SDA', 'ch': 7, 'desc': 'Serial data line'}
+# ...
+#
+# {'inbuf': [...],
+#  'signals': [{'SCL': }]}
+#
 
-def sigrokdecode_i2c(inbuf):
+def decode(inbuf):
 	"""I2C protocol decoder"""
 
+	# FIXME: Get the data in the correct format in the first place.
+	inbuf = [ord(x) for x in inbuf]
+
 	# FIXME: This should be passed in as metadata, not hardcoded here.
-	signals = (2, 5)
-	channels = 8
+	metadata = {
+	  'numchannels': 8,
+	  'signals': {
+	      'scl': {'ch': 5, 'name': 'SCL', 'desc': 'Serial clock line'},
+	      'sda': {'ch': 7, 'name': 'SDA', 'desc': 'Serial data line'},
+	    },
+	}
 
 	o = wr = ack = d = ''
 	bitcount = data = 0
-	state = 'IDLE'
+	IDLE, START, ADDRESS, DATA = range(4)
+	state = IDLE
 
-	# Get the bit number (and thus probe index) of the SCL/SDA signals.
-	scl_bit, sda_bit = signals
+	# Get the channel/probe number of the SCL/SDA signals.
+	scl_bit = metadata['signals']['scl']['ch']
+	sda_bit = metadata['signals']['sda']['ch']
 
 	# Get SCL/SDA bit values (0/1 for low/high) of the first sample.
-	s = ord(inbuf[0])
-	oldscl = (s & (1 << scl_bit)) != 0
-	oldsda = (s & (1 << sda_bit)) != 0
+	s = inbuf[0]
+	oldscl = (s & (1 << scl_bit)) >> scl_bit
+	oldsda = (s & (1 << sda_bit)) >> sda_bit
 
 	# Loop over all samples.
 	# TODO: Handle LAs with more/less than 8 channels.
 	for samplenum, s in enumerate(inbuf[1:]): # We skip the first byte...
- 
-		s = ord(s) # FIXME
-
 		# Get SCL/SDA bit values (0/1 for low/high).
-		scl = (s & (1 << scl_bit)) != 0
-		sda = (s & (1 << sda_bit)) != 0
+		scl = (s & (1 << scl_bit)) >> scl_bit
+		sda = (s & (1 << sda_bit)) >> sda_bit
 
 		# TODO: Wait until the bus is idle (SDA = SCL = 1) first?
 
 		# START condition (S): SDA = falling, SCL = high
 		if (oldsda == 1 and sda == 0) and scl == 1:
 			o += "%d\t\tSTART\n" % samplenum
-			state = 'ADDRESS'
+			state = ADDRESS
 			bitcount = data = 0
 
 		# Data latching by transmitter: SCL = low
@@ -125,20 +189,21 @@ def sigrokdecode_i2c(inbuf):
 
 			# We received 8 address/data bits and the ACK/NACK bit.
 			data >>= 1 # Shift out unwanted ACK/NACK bit here.
-			o += "%d\t\t%s: " % (samplenum, state)
+			# o += "%d\t\t%s: " % (samplenum, state)
+			o += "%d\t\tTODO:STATE: " % samplenum
 			ack = (sda == 1) and 'NACK' or 'ACK'
-			d = (state == 'ADDRESS') and (data & 0xfe) or data
+			d = (state == ADDRESS) and (data & 0xfe) or data
 			wr = ''
-			if state == 'ADDRESS':
+			if state == ADDRESS:
 				wr = (data & 1) and ' (W)' or ' (R)'
-				state = 'DATA'
+				state = DATA
 			o += "0x%02x%s (%s)\n" % (d, wr, ack)
 			bitcount = data = 0
 
 		# STOP condition (P): SDA = rising, SCL = high
 		elif (oldsda == 0 and sda == 1) and scl == 1:
 			o += "%d\t\tSTOP\n" % samplenum
-			state = 'IDLE'
+			state = IDLE
 
 		# Save current SDA/SCL values for the next round.
 		oldscl = scl
@@ -146,19 +211,23 @@ def sigrokdecode_i2c(inbuf):
 
 	return o
 
-# This is just a draft.
-def sigrokdecode_register_i2c():
-	metadata = {
+def register():
+	return {
 		'id': 'i2c',
 		'name': 'I2C',
-		'description': 'Inter-Integrated Circuit (I2C) bus',
-		'function': 'sigrokdecode_i2c',
+		'desc': 'Inter-Integrated Circuit (I2C) bus',
 		'inputformats': ['raw'],
 		'signalnames':  {
 				'SCL': 'Serial clock line',
 				'SDA': 'Serial data line',
 				},
-		'ouputformats': ['i2c', 'ascii'],
+		'outputformats': ['i2c'],
 	}
-	return metadata
+
+# Use psyco (if available) as it results in huge performance improvements.
+try:
+	import psyco
+	psyco.bind(decode)
+except ImportError:
+	pass