## 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
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
##
-# I2S protocol decoder
-
import sigrokdecode as srd
-# Annotation formats
-ANN_HEX = 0
+'''
+OUTPUT_PYTHON format:
+
+Packet:
+[<ptype>, <pdata>]
+
+<ptype>, <pdata>:
+ - 'DATA', [<channel>, <value>]
+
+<channel>: 'L' or 'R'
+<value>: integer
+'''
+
+class SamplerateError(Exception):
+ pass
class Decoder(srd.Decoder):
- api_version = 1
+ api_version = 3
id = 'i2s'
- name = 'I2S'
+ name = 'I²S'
longname = 'Integrated Interchip Sound'
desc = 'Serial bus for connecting digital audio devices.'
license = 'gplv2+'
inputs = ['logic']
outputs = ['i2s']
- probes = [
+ channels = (
{'id': 'sck', 'name': 'SCK', 'desc': 'Bit clock line'},
{'id': 'ws', 'name': 'WS', 'desc': 'Word select line'},
{'id': 'sd', 'name': 'SD', 'desc': 'Serial data line'},
- ]
- optional_probes = []
- options = {}
- annotations = [
- ['Hex', 'Annotations in hex format'],
- ]
-
- def __init__(self, **kwargs):
- self.oldsck = 1
+ )
+ annotations = (
+ ('left', 'Left channel'),
+ ('right', 'Right channel'),
+ ('warnings', 'Warnings'),
+ )
+ binary = (
+ ('wav', 'WAV file'),
+ )
+
+ def __init__(self):
+ self.samplerate = None
self.oldws = 1
self.bitcount = 0
self.data = 0
self.samplesreceived = 0
self.first_sample = None
- self.start_sample = None
+ self.ss_block = None
self.wordlength = -1
+ self.wrote_wav_header = False
+
+ def start(self):
+ self.out_python = self.register(srd.OUTPUT_PYTHON)
+ self.out_binary = self.register(srd.OUTPUT_BINARY)
+ self.out_ann = self.register(srd.OUTPUT_ANN)
+
+ def metadata(self, key, value):
+ if key == srd.SRD_CONF_SAMPLERATE:
+ self.samplerate = value
+
+ def putpb(self, data):
+ self.put(self.ss_block, self.samplenum, self.out_python, data)
+
+ def putbin(self, data):
+ self.put(self.ss_block, self.samplenum, self.out_binary, data)
- def start(self, metadata):
- self.samplerate = metadata['samplerate']
- self.out_proto = self.add(srd.OUTPUT_PROTO, 'i2s')
- self.out_ann = self.add(srd.OUTPUT_ANN, 'i2s')
+ def putb(self, data):
+ self.put(self.ss_block, self.samplenum, self.out_ann, data)
def report(self):
# Calculate the sample rate.
samplerate = '?'
- if self.start_sample != None and \
- self.first_sample != None and \
- self.start_sample > self.first_sample:
+ if self.ss_block is not None and \
+ self.first_sample is not None and \
+ self.ss_block > self.first_sample:
samplerate = '%d' % (self.samplesreceived *
- self.samplerate / (self.start_sample -
+ self.samplerate / (self.ss_block -
self.first_sample))
- return 'I2S: %d %d-bit samples received at %sHz' % \
+ return 'I²S: %d %d-bit samples received at %sHz' % \
(self.samplesreceived, self.wordlength, samplerate)
- def decode(self, ss, es, data):
- for samplenum, (sck, ws, sd) in data:
-
- # Ignore sample if the bit clock hasn't changed.
- if sck == self.oldsck:
- continue
-
- self.oldsck = sck
- if sck == 0: # Ignore the falling clock edge.
- continue
+ def wav_header(self):
+ # Chunk descriptor
+ h = b'RIFF'
+ h += b'\x24\x80\x00\x00' # Chunk size (2084)
+ h += b'WAVE'
+ # Fmt subchunk
+ h += b'fmt '
+ h += b'\x10\x00\x00\x00' # Subchunk size (16 bytes)
+ h += b'\x01\x00' # Audio format (0x0001 == PCM)
+ h += b'\x02\x00' # Number of channels (2)
+ h += b'\x80\x3e\x00\x00' # Samplerate (16000)
+ h += b'\x00\x7d\x00\x00' # Byterate (32000)
+ h += b'\x04\x00' # Blockalign (4)
+ h += b'\x10\x00' # Bits per sample (16)
+ # Data subchunk
+ h += b'data'
+ h += b'\xff\xff\x00\x00' # Subchunk size (65535 bytes) TODO
+ return h
+
+ def wav_sample(self, sample):
+ # TODO: This currently assumes U32 samples, and converts to S16.
+ s = sample >> 16
+ if s >= 0x8000:
+ s -= 0x10000
+ lo, hi = s & 0xff, (s >> 8) & 0xff
+ return bytes([lo, hi])
+
+ def decode(self):
+ if not self.samplerate:
+ raise SamplerateError('Cannot decode without samplerate.')
+ while True:
+ # Wait for a rising edge on the SCK pin.
+ sck, ws, sd = self.wait({0: 'r'})
self.data = (self.data << 1) | sd
self.bitcount += 1
continue
# Only submit the sample, if we received the beginning of it.
- if self.start_sample != None:
+ if self.ss_block is not None:
+
+ if not self.wrote_wav_header:
+ self.put(0, 0, self.out_binary, [0, self.wav_header()])
+ self.wrote_wav_header = True
+
self.samplesreceived += 1
- self.put(self.start_sample, samplenum, self.out_proto,
- ['data', self.data])
- self.put(self.start_sample, samplenum, self.out_ann,
- [ANN_HEX, ['%s: 0x%08x' % ('L' if self.oldws else 'R',
- self.data)]])
+
+ idx = 0 if self.oldws else 1
+ c1 = 'Left channel' if self.oldws else 'Right channel'
+ c2 = 'Left' if self.oldws else 'Right'
+ c3 = 'L' if self.oldws else 'R'
+ v = '%08x' % self.data
+ self.putpb(['DATA', [c3, self.data]])
+ self.putb([idx, ['%s: %s' % (c1, v), '%s: %s' % (c2, v),
+ '%s: %s' % (c3, v), c3]])
+ self.putbin([0, self.wav_sample(self.data)])
# Check that the data word was the correct length.
if self.wordlength != -1 and self.wordlength != self.bitcount:
- self.put(self.start_sample, samplenum, self.out_ann,
- [ANN_HEX, ['WARNING: Received a %d-bit word, when a '
- '%d-bit word was expected' % (self.bitcount,
- self.wordlength)]])
+ self.putb([2, ['Received %d-bit word, expected %d-bit '
+ 'word' % (self.bitcount, self.wordlength)]])
self.wordlength = self.bitcount
# Reset decoder state.
self.data = 0
self.bitcount = 0
- self.start_sample = samplenum
+ self.ss_block = self.samplenum
# Save the first sample position.
- if self.first_sample == None:
- self.first_sample = samplenum
+ if self.first_sample is None:
+ self.first_sample = self.samplenum
self.oldws = ws
-
projects / libsigrokdecode.git / blobdiff