## along with this program; if not, see <http://www.gnu.org/licenses/>.
##
+from common.srdhelper import bitpack_lsb
import sigrokdecode as srd
class Pin:
self.reset()
def reset(self):
- self.ss = self.es = self.ss_byte = -1
- self.bitcount = 0
- self.databyte = 0
self.bits = []
- self.cmd = 'RESET'
+ self.cmd = None
def metadata(self, key, value):
if key == srd.SRD_CONF_SAMPLERATE:
self.out_ann = self.register(srd.OUTPUT_ANN)
self.out_binary = self.register(srd.OUTPUT_BINARY)
- def putx(self, data):
- self.put(self.ss, self.es, self.out_ann, data)
+ def putx(self, ss, es, cls, data):
+ self.put(ss, es, self.out_ann, [cls, data,])
- def putb(self, data):
- self.put(self.ss, self.es, self.out_binary, data)
+ def putb(self, ss, es, cls , data):
+ self.put(ss, es, self.out_binary, [cls, data,])
def handle_reset(self, pins):
- self.ss, self.es = self.samplenum, self.samplenum
self.cmd = 'RESET'
cls, texts = lookup_proto_ann_txt(self.cmd, {})
- self.putx([cls, texts])
- self.bitcount = self.databyte = 0
+ self.putx(self.samplenum, self.samplenum, cls, texts)
self.bits = []
- self.cmd = 'ATR' # Next data bytes will be ATR
+ # Next data bytes will be Answer To Reset.
+ self.cmd = 'ATR'
def handle_command(self, pins):
rst, clk, io = pins
- self.ss, self.es = self.samplenum, self.samplenum
+ # XXX Is the comment inverted?
# If I/O is rising -> command START
# if I/O is falling -> command STOP and response data incoming
- self.cmd = 'CMD' if (io == 0) else 'DATA'
- self.bitcount = self.databyte = 0
+ self.cmd = 'CMD' if io == 0 else 'DATA'
self.bits = []
# Gather 8 bits of data
def handle_data(self, pins):
rst, clk, io = pins
- # Data is transmitted LSB-first.
- self.databyte |= (io << self.bitcount)
-
- # Remember the start of the first data/address bit.
- if self.bitcount == 0:
- self.ss_byte = self.samplenum
-
- # Store individual bits and their start/end samplenumbers.
- # In the list, index 0 represents the LSB (SLE44xx transmits LSB-first).
- self.bits.insert(0, [io, self.samplenum, self.samplenum])
- if self.bitcount > 0:
- self.bits[1][2] = self.samplenum
- if self.bitcount == 7:
- self.bitwidth = self.bits[1][2] - self.bits[2][2]
- self.bits[0][2] += self.bitwidth
-
- # Return if we haven't collected all 8 bits, yet.
- if self.bitcount < 7:
- self.bitcount += 1
+ # Remember the start of the first data/address bit. Collect
+ # bits in LSB first order. "Estimate" the bit's width at first,
+ # update end times as better data becomes available.
+ # TODO This estimation logic is imprecise and fragile. A single
+ # slightly stretched clock period throws off the following bit
+ # annotation. Better look for more reliable conditions. Available
+ # documentation suggests bit values are valid during high CLK.
+ bit_val = io
+ bit_ss = self.samplenum
+ bit_es = bit_ss # self.bitwidth is not known yet.
+ if self.bits:
+ self.bits[-1][2] = bit_ss
+ self.bits.append([bit_val, bit_ss, bit_es])
+ if len(self.bits) < 8:
return
+ bitwidth = self.bits[-1][1] - self.bits[-2][1]
+ self.bits[-1][2] += bitwidth
- self.ss, self.es = self.ss_byte, self.samplenum + self.bitwidth
+ # Get the data byte value, and byte's ss/es.
+ databyte = bitpack_lsb(self.bits, 0)
+ byte_ss = self.bits[0][1]
+ byte_es = self.bits[-1][2]
- self.putb([Bin.SEND_DATA, bytes([self.databyte])])
+ self.putb(byte_ss, byte_es, Bin.SEND_DATA, bytes([databyte]))
+ # TODO Present bit values earlier. As soon as their es is known.
for bit_val, bit_ss, bit_es in self.bits:
cls, texts = lookup_proto_ann_txt('BIT', {'bit': bit_val})
- self.put(bit_ss, bit_es, self.out_ann, [cls, texts])
+ self.putx(bit_ss, bit_es, cls, texts)
- cls, texts = lookup_proto_ann_txt(self.cmd, {'data': self.databyte})
- self.putx([cls, texts])
+ cls, texts = lookup_proto_ann_txt(self.cmd, {'data': databyte})
+ if cls:
+ self.putx(byte_ss, byte_es, cls, texts)
# Done with this packet.
- self.bitcount = self.databyte = 0
self.bits = []
def decode(self):
# Signal conditions tracked by the protocol decoder:
# - RESET condition (R): RST = rising
# - Incoming data (D): RST = low, CLK = rising.
+ # TODO Add "RST low, CLK fall" for "end of DATA" here?
# - Command mode START: CLK = high, I/O = falling.
# - Command mode STOP: CLK = high, I/O = rising.
(COND_RESET, COND_DATA, COND_CMD_START, COND_CMD_STOP,) = range(4)