# This decoder extracts a DDC stream from an I2C session between a computer
# and a display device. The stream is output as plain bytes.
#
+# Details:
+# https://en.wikipedia.org/wiki/Display_Data_Channel
+#
-import sigrokdecode
-
+import sigrokdecode as srd
-class Decoder(sigrokdecode.Decoder):
+class Decoder(srd.Decoder):
id = 'ddc'
name = 'DDC'
longname = 'Display Data Channel'
- desc = 'DDC is a protocol for communication between computers and displays.'
+ desc = 'A protocol for communication between computers and displays.'
longdesc = ''
author = 'Bert Vermeulen <bert@biot.com>'
+ email = '<bert@biot.com>'
license = 'gplv3+'
inputs = ['i2c']
outputs = ['ddc']
- annotation = [
- ["Byte stream", "DDC byte stream as read from display."],
+ probes = []
+ options = {}
+ annotations = [
+ ['Byte stream', 'DDC byte stream as read from display.'],
]
def __init__(self, **kwargs):
self.state = None
def start(self, metadata):
- self.out_ann = self.add(sigrokdecode.SRD_OUTPUT_ANN, 'ddc')
+ self.out_ann = self.add(srd.OUTPUT_ANN, 'ddc')
- def decode(self, start_sample, end_sample, i2c_data):
+ def decode(self, ss, es, data):
try:
- cmd, data, ack_bit = i2c_data
+ cmd, data, ack_bit = data
except Exception as e:
- raise Exception("malformed I2C input: %s" % str(e)) from e
+ raise Exception('malformed I2C input: %s' % str(e)) from e
if self.state is None:
- # waiting for the DDC session to start
+ # Wait for the DDC session to start.
if cmd in ('START', 'START_REPEAT'):
self.state = 'start'
elif self.state == 'start':
# so this marks the start of the DDC data transfer.
self.state = 'transfer'
elif cmd == 'STOP':
- # back to idle
+ # Got back to the idle state.
self.state = None
elif self.state == 'transfer':
if cmd == 'DATA_READ':
- # there shouldn't be anything but data reads on this
- # address, so ignore everything else
- self.put(start_sample, end_sample, self.out_ann,
- [0, ["0x%.2x" % data]])
+ # There shouldn't be anything but data reads on this
+ # address, so ignore everything else.
+ self.put(ss, es, self.out_ann, [0, ['0x%.2x' % data]])