##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2012-2013 Uwe Hermann <uwe@hermann-uwe.de>
## Copyright (C) 2019 Stephan Thiele <stephan.thiele@mailbox.org>
## Copyright (C) 2024 DreamSourceLab <support@dreamsourcelab.com>
##
## 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/>.
##

##
## 2023/12/29 DreamSourceLab : add parity check and graycode check
## 2024/3/28 DreamSourceLab : Display data when zooming out 
##

from common.srdhelper import bitpack_msb
import sigrokdecode as srd

class SamplerateError(Exception):
    pass

def dlc2len(dlc):
    return [0, 1, 2, 3, 4, 5, 6, 7, 8, 12, 16, 20, 24, 32, 48, 64][dlc]

def ParityCheck(value):
    paritycheck = False
    parity = [0,3,5,6,9,10,12,15]
    for parityvalue in parity:
        if parityvalue == value:
            paritycheck = True
            break
    return paritycheck

def gray_to_binary(gray_code):
    binary_code = gray_code[0]
    for i in range(1, len(gray_code)):
        if gray_code[i] == '0':
            binary_code += binary_code[i - 1]
        else:
            binary_code += '1' if binary_code[i - 1] == '0' else '0'
    return binary_code

class Decoder(srd.Decoder):
    api_version = 3
    id = 'can-fd'
    name = 'CAN-FD'
    longname = 'Controller Area Network with Flexible Data rate'
    desc = 'Field bus protocol for distributed realtime control.'
    license = 'gplv2+'
    inputs = ['logic']
    outputs = ['can']
    tags = ['Automotive']
    channels = (
        {'id': 'can_rx', 'name': 'CAN FD', 'desc': 'CAN FD bus line', 'idn':'dec_can_chan_can_rx'},
    )
    options = (
        {'id': 'nominal_bitrate', 'desc': 'Nominal bitrate (bits/s)', 'default': 1000000, 'idn':'dec_can_opt_nominal_bitrate'},
        {'id': 'fast_bitrate', 'desc': 'Fast bitrate (bits/s)', 'default': 2000000, 'idn':'dec_can_opt_fast_bitrate'},
        {'id': 'sample_point', 'desc': 'Sample point (%)', 'default': 70.0, 'idn':'dec_can_opt_sample_point'},
    )
    annotations = (
        ('data', 'CAN payload data'),
        ('sof', 'Start of frame'),
        ('eof', 'End of frame'),
        ('id', 'Identifier'),
        ('ext-id', 'Extended identifier'),
        ('full-id', 'Full identifier'),
        ('ide', 'Identifier extension bit'),
        ('reserved-bit', 'Reserved bit 0 and 1'),
        ('rtr', 'Remote transmission request'),
        ('srr', 'Substitute remote request'),
        ('dlc', 'Data length count'),
        ('crc-sequence', 'CRC sequence'),
        ('crc-delimiter', 'CRC delimiter'),
        ('ack-slot', 'ACK slot'),
        ('ack-delimiter', 'ACK delimiter'),
        ('stuff-bit', 'Stuff bit'),
        ('warnings', 'Human-readable warnings'),
        ('bit', 'Bit'),
    )
    annotation_rows = (
        ('bits', 'Bits', (15, 17)),
        ('fields', 'Fields', tuple(range(15))),
        ('warnings', 'Warnings', (16,)),
    )

    def __init__(self):
        self.reset()

    def reset(self):
        self.samplerate = None
        self.reset_variables()

    def start(self):
        self.out_ann = self.register(srd.OUTPUT_ANN)
        self.out_python = self.register(srd.OUTPUT_PYTHON)

    def set_bit_rate(self, bitrate):
        self.bit_width = float(self.samplerate) / float(bitrate)
        self.sample_point = (self.bit_width / 100.0) * self.options['sample_point']

    def set_nominal_bitrate(self):
        self.set_bit_rate(self.options['nominal_bitrate'])


    def set_fast_bitrate(self):
        self.set_bit_rate(self.options['fast_bitrate'])


    def metadata(self, key, value):
        if key == srd.SRD_CONF_SAMPLERATE:
            self.samplerate = value

            self.bit_width = float(self.samplerate) / float(self.options['nominal_bitrate'])
            self.sample_point = (self.bit_width / 100.0) * self.options['sample_point']

    # Generic helper for CAN bit annotations.
    def putg(self, ss, es, data):
        left, right = int(self.sample_point), int(self.bit_width - self.sample_point)
        self.put(ss - left, es + right, self.out_ann, data)

    # Single-CAN-bit annotation using the current samplenum.
    def putx(self, data):
        self.putg(self.samplenum, self.samplenum, data)

    # Single-CAN-bit annotation using the samplenum of CAN bit 12.
    def put12(self, data):
        self.putg(self.ss_bit12, self.ss_bit12, data)

    # Single-CAN-bit annotation using the samplenum of CAN bit 32.
    def put32(self, data):
        self.putg(self.ss_bit32, self.ss_bit32, data)

    # Multi-CAN-bit annotation from self.ss_block to current samplenum.
    def putb(self, data):
        self.putg(self.ss_block, self.samplenum, data)

    def putpy(self, data):
        self.put(self.ss_packet, self.es_packet, self.out_python, data)

    def reset_variables(self):
        self.state = 'IDLE'
        self.sof = self.frame_type = self.dlc = None
        self.rawbits = [] # All bits, including stuff bits
        self.bits = [] # Only actual CAN frame bits (no stuff bits)
        self.curbit = 0 # Current bit of CAN frame (bit 0 == SOF)
        self.last_databit = 999 # Positive value that bitnum+x will never match
        self.ss_block = None
        self.ss_bit12 = None
        self.ss_bit32 = None
        self.ss_databytebits = []
        self.frame_bytes = []
        self.rtr_type = None
        self.fd = False
        self.rtr = None
        self.crc_data = []

        #Parity Calculate
        self.stuff_count_start = None
        self.stuff_count = 0 


    # Poor man's clock synchronization. Use signal edges which change to
    # dominant state in rather simple ways. This naive approach is neither
    # aware of the SYNC phase's width nor the specific location of the edge,
    # but improves the decoder's reliability when the input signal's bitrate
    # does not exactly match the nominal rate.
    def dom_edge_seen(self, force = False):
        self.dom_edge_snum = self.samplenum
        self.dom_edge_bcount = self.curbit

    # Determine the position of the next desired bit's sample point.

    def get_sample_point(self, bitnum):

        samplenum = self.dom_edge_snum
        samplenum += self.bit_width * (bitnum - self.dom_edge_bcount)
        samplenum += self.sample_point
        return int(samplenum)

    def is_stuff_bit(self):
        # CAN uses NRZ encoding and bit stuffing.
        # After 5 identical bits, a stuff bit of opposite value is added.
        # But not in the CRC delimiter, ACK, and end of frame fields.


        if len(self.bits) > self.last_databit + 17:
            return False

        if self.fd and len(self.bits) > self.last_databit + 1:
            return False

        last_6_bits = self.rawbits[-6:]
        if last_6_bits not in ([0, 0, 0, 0, 0, 1], [1, 1, 1, 1, 1, 0]):
            return False

        self.stuff_count = self.stuff_count + 1

        # Stuff bit. Keep it in self.rawbits, but drop it from self.bits.
        self.bits.pop() # Drop last bit.
        return True

    def is_valid_crc(self, crc_bits,crc_type):
        return True # TODO

    def decode_error_frame(self, bits):
        pass # TODO

    def decode_overload_frame(self, bits):
        pass # TODO

    # Both standard and extended frames end with CRC, CRC delimiter, ACK,
    # ACK delimiter, and EOF fields. Handle them in a common function.
    # Returns True if the frame ended (EOF), False otherwise.


    def decode_frame_end(self, can_rx, bitnum):


        # Remember start of CRC sequence (see below).
        if bitnum == (self.last_databit + 1):

            self.ss_block = self.samplenum

            if self.fd:
                if dlc2len(self.dlc) <= 16:
                    self.crc_len = 27 # 17 + SBC + stuff bits
                else:
                    self.crc_len = 32 # 21 + SBC + stuff bits
                self.putx([15, ['Fixed stuff bit: %d' % can_rx, 'FSB: %d' % can_rx, '%d' % can_rx]])
            else:
                self.crc_len = 15

        elif self.fd and bitnum == (self.last_databit + 2):
            self.ss_block = self.samplenum
            # stuff count start
            self.stuff_count_start = self.samplenum


        elif self.fd and bitnum == (self.last_databit + 4):

            stuff_bits = self.bits[-3:]

            stuff_count = '{0:b}'.format(bitpack_msb(stuff_bits))
            while len(stuff_count) != 3:
                stuff_count = '0' + stuff_count

            stuff_count_bin = gray_to_binary(stuff_count)
            stuff_count_bin_val = int(stuff_count_bin,2)

            if self.stuff_count %  8 != stuff_count_bin_val:
                self.putb([16,['Gray Code Error','GCE','GCE']])
            self.stuff_count = 0

            self.putb([11,['Stuff count: %s' % stuff_count,
                'Stuff count: %s' % stuff_count, '%s' % stuff_count]])
            self.ss_block = self.samplenum +int(self.bit_width)


        elif self.fd and bitnum == (self.last_databit + 5):
            stuff_and_parity_bits = self.bits[-4:]
            stuff_and_parity = bitpack_msb(stuff_and_parity_bits)
            if ParityCheck(stuff_and_parity) == False:
                self.putg(self.stuff_count_start,self.samplenum,[16,['Parity Check Error','PCE','PCE']])
            self.putx([11,['Parity: %d' % can_rx, 'P: %d' % can_rx, '%d' % can_rx]])
            self.ss_block = self.samplenum +int(self.bit_width)

        elif self.fd and bitnum > (self.last_databit + 5) and bitnum < (self.last_databit + self.crc_len):
            index = bitnum - (self.last_databit + 5)
            if((index-1)%5 == 0):
                self.putx([15, ['Fixed stuff bit: %d' % can_rx, 'FSB: %d' % can_rx, '%d' % can_rx]])
            if(index%5 == 0):
                self.crc_data += self.bits[-4:]

        # CRC sequence (15 bits, 17 bits or 21 bits)
        elif bitnum == (self.last_databit + self.crc_len):
            if self.fd:
                if dlc2len(self.dlc) <= 16:
                    crc_type = "CRC-17"
                else:
                    crc_type = "CRC-21"
            else:
                crc_type = "CRC-15"

            x = self.last_databit + 1
            crc_bits = self.bits[x:x + self.crc_len + 1]
            if self.fd:
                self.crc_data.append(can_rx)
                self.crc = bitpack_msb(self.crc_data)
            else:
                self.crc = bitpack_msb(crc_bits)
            self.putb([11, ['%s sequence: 0x%04x' % (crc_type, self.crc),
                            '%s: 0x%04x' % (crc_type, self.crc), '0x%04x' % self.crc]])
            if not self.is_valid_crc(crc_bits,crc_type):
                self.putb([16, ['CRC is invalid']])

        # CRC delimiter bit (recessive)
        elif bitnum == (self.last_databit + self.crc_len + 1):
            self.putx([12, ['CRC delimiter: %d' % can_rx,
                            'CRC d: %d' % can_rx, '%d' % can_rx]])
            if can_rx != 1:
                self.putx([16, ['CRC delimiter must be a recessive bit']])

            if self.fd:
                self.set_nominal_bitrate()

        # ACK slot bit (dominant: ACK, recessive: NACK)
        elif bitnum == (self.last_databit + self.crc_len + 2):
            ack = 'ACK' if can_rx == 0 else 'NACK'
            self.putx([13, ['ACK slot: %s' % ack, 'ACK s: %s' % ack, '%s' % ack]])

        # ACK delimiter bit (recessive)
        elif bitnum == (self.last_databit + self.crc_len + 3):
            self.putx([14, ['ACK delimiter: %d' % can_rx,
                            'ACK d: %d' % can_rx, '%d' % can_rx]])
            if can_rx != 1:
                self.putx([16, ['ACK delimiter must be a recessive bit']])

        # Remember start of EOF (see below).
        elif bitnum == (self.last_databit + self.crc_len + 4):
            self.ss_block = self.samplenum

        # End of frame (EOF), 7 recessive bits
        elif bitnum == (self.last_databit + self.crc_len + 10):
            self.putb([2, ['End of frame', 'EOF', 'E']])
            if self.rawbits[-7:] != [1, 1, 1, 1, 1, 1, 1]:
                self.putb([16, ['End of frame (EOF) must be 7 recessive bits']])
            self.es_packet = self.samplenum
            py_data = tuple([self.frame_type, self.fullid, self.rtr_type,
                self.dlc, self.frame_bytes])
            self.putpy(py_data)
            self.reset_variables()
            return True

        return False

    # Returns True if the frame ended (EOF), False otherwise.
    def decode_standard_frame(self, can_rx, bitnum):

        # Bit 14: FDF (Flexible data format)
        # Has to be sent dominant when FD frame, has to be sent recessive
        # when classic CAN frame.
        if bitnum == 14:
            self.fd = True if can_rx else False
            self.putx([7, ['Flexible data format: %d' % can_rx,
                            'FDF: %d' % can_rx, '%d' % can_rx]])
            if self.fd:
                #Bit 12: Remote request subtitution' (RRS) bit
                self.put12([8, ['Remote request subtitution', 'RRS']])
                self.dlc_start = 18
            else:
                # Bit 12: Remote transmission request (RTR) bit
                # Data frame: dominant, remote frame: recessive
                # Remote frames do not contain a data field.
                rtr = 'remote' if self.bits[12] == 1 else 'data'
                self.put12([8, ['Remote transmission request: %s frame' % rtr,
                                'RTR: %s frame' % rtr, '%s' % rtr]])
                self.rtr_type = rtr
                self.dlc_start = 15

        if bitnum == 15 and self.fd:
            self.putx([7, ['Reserved bit 0: %d' % can_rx, 'RB0: %d' % can_rx, '%d' % can_rx]])

        if bitnum == 16 and self.fd:
            self.putx([7, ['Bit rate switch: %d' % can_rx, 'BRS: %d' % can_rx, '%d' % can_rx]])

        if bitnum == 17 and self.fd:
            self.putx([7, ['Error state indicator: %d' % can_rx, 'ESI: %d' % can_rx, '%d' % can_rx]])

        # Remember start of DLC (see below).
        elif bitnum == self.dlc_start:
            self.ss_block = self.samplenum

        # Bits 15-18: Data length code (DLC), in number of bytes (0-8).
        elif bitnum == self.dlc_start + 3:
            self.dlc = bitpack_msb(self.bits[self.dlc_start:self.dlc_start + 4])
            self.putb([10, ['Data length code: %d' % self.dlc,
                            'DLC: %d' % self.dlc, '%d' % self.dlc]])
            self.last_databit = self.dlc_start + 3 + (dlc2len(self.dlc) * 8)
            if self.dlc != 0 and self.rtr_type == 'remote':
                self.putb([16, ['Data length code (DLC) != 0 is not allowed']])
                self.dlc = 0
                self.last_databit = self.dlc_start + 3 + (dlc2len(self.dlc) * 8)
            elif self.dlc > 8 and not self.fd:
                self.putb([16, ['CAN Data length code (DLC) > 8 is not allowed']])
                self.dlc = 8
                self.last_databit = self.dlc_start + 3 + (dlc2len(self.dlc) * 8)


        # Remember all databyte bits, except the very last one.
        elif bitnum in range(self.dlc_start + 4, self.last_databit):
            self.ss_databytebits.append(self.samplenum)

        # Bits 19-X: Data field (0-8 bytes, depending on DLC)
        # The bits within a data byte are transferred MSB-first.
        elif bitnum == self.last_databit:
            self.ss_databytebits.append(self.samplenum) # Last databyte bit.
            for i in range(dlc2len(self.dlc)):
                x = self.dlc_start + 4 + (8 * i)
                b = bitpack_msb(self.bits[x:x + 8])
                self.frame_bytes.append(b)
                ss = self.ss_databytebits[i * 8]
                es = self.ss_databytebits[((i + 1) * 8) - 1]
                self.putg(ss, es, [0, ['Data byte %d: 0x%02x' % (i, b),
                                       'DB %d: 0x%02x' % (i, b), '0x%02x' % b]])
            self.ss_databytebits = []

        elif bitnum > self.last_databit:
            return self.decode_frame_end(can_rx, bitnum)

        return False

    # Returns True if the frame ended (EOF), False otherwise.
    def decode_extended_frame(self, can_rx, bitnum):

        # Remember start of EID (see below).
        if bitnum == 14:
            self.ss_block = self.samplenum
            self.dlc_start = 35

        # Bits 14-31: Extended identifier (EID[17..0])
        elif bitnum == 31:
            self.eid = bitpack_msb(self.bits[14:])
            s = '%d (0x%x)' % (self.eid, self.eid)
            self.putb([4, ['Extended Identifier: %s' % s,
                           'Extended ID: %s' % s, 'Extended ID', '%s' % s]])

            self.fullid = self.ident << 18 | self.eid
            s = '%d (0x%x)' % (self.fullid, self.fullid)
            self.putb([5, ['Full Identifier: %s' % s, 'Full ID: %s' % s,
                           '%s' %s]])

            # Bit 12: Substitute remote request (SRR) bit
            self.put12([9, ['Substitute remote request: %d' % self.bits[12],
                            'SRR: %d' % self.bits[12], '%d' % self.bits[12]]])

        # Bit 32: Remote transmission request (RTR) bit
        # Data frame: dominant, remote frame: recessive
        # Remote frames do not contain a data field.

        # Remember start of RTR (see below).
        if bitnum == 32:
            self.ss_bit32 = self.samplenum
            self.rtr = can_rx

        # Bit 33: RB1 (reserved bit) or FDF(Flexible data format)
        elif bitnum == 33:
            self.fd = True if can_rx else False
            self.putx([7, ['Flexible data format: %d' % can_rx,
                'FDF: %d' % can_rx, '%d' % can_rx]])
            if self.fd:
                self.put32([7, ['Remote requset substituion: %d' % self.rtr,
                                'RRS: %d' % self.rtr, '%d' % self.rtr]])
                self.dlc_start = 37
            else:
                rtr = 'remote' if self.rtr == 1 else 'data'
                self.rtr_type = rtr
                self.put32([8, ['Remote transmission request: %s frame' % rtr,
                              'RTR: %s frame' % rtr, '%s' % rtr]])
                self.dlc_start = 35

        # Bit 34: RB0 (reserved bit)
        elif bitnum == 34:
            self.putx([7, ['Reserved bit 0: %d' % can_rx,
                           'RB0: %d' % can_rx, '%d' % can_rx]])

        elif bitnum == 35 and self.fd:
            self.putx([7, ['Bit rate switch: %d' % can_rx,
                           'BRS: %d' % can_rx, '%d' % can_rx]])

        elif bitnum == 36 and self.fd:
            self.putx([7, ['Error state indicator: %d' % can_rx,
                           'ESI: %d' % can_rx, '%d' % can_rx]])

        # Remember start of DLC (see below).
        elif bitnum == self.dlc_start:
            self.ss_block = self.samplenum

        # Bits 35-38: Data length code (DLC), in number of bytes (0-8).
        elif bitnum == self.dlc_start + 3:
            self.dlc = bitpack_msb(self.bits[self.dlc_start:self.dlc_start + 4])
            self.putb([10, ['Data length code: %d' % self.dlc,
                            'DLC: %d' % self.dlc, '%d' % self.dlc]])
            self.last_databit = self.dlc_start + 3 + (dlc2len(self.dlc) * 8)
            #if rtr == remote then dlc = 0
            if self.dlc != 0 and self.rtr_type == 'remote':
                self.dlc = 0
                self.last_databit = self.dlc_start + 3 + (dlc2len(self.dlc) * 8)
            #if dlc > 8 then dlc = 8
            elif self.dlc > 8 and not self.fd:
                self.dlc = 8
                self.last_databit = self.dlc_start + 3 + (dlc2len(self.dlc) * 8)

        # Remember all databyte bits, except the very last one.
        elif bitnum in range(self.dlc_start + 4, self.last_databit):
            self.ss_databytebits.append(self.samplenum)

        # Bits 39-X: Data field (0-8 bytes, depending on DLC)
        # The bits within a data byte are transferred MSB-first.
        elif bitnum == self.last_databit:
            self.ss_databytebits.append(self.samplenum) # Last databyte bit.
            for i in range(dlc2len(self.dlc)):
                x = self.dlc_start + 4 + (8 * i)
                b = bitpack_msb(self.bits[x:x + 8])
                self.frame_bytes.append(b)
                ss = self.ss_databytebits[i * 8]
                es = self.ss_databytebits[((i + 1) * 8) - 1]
                self.putg(ss, es, [0, ['Data byte %d: 0x%02x' % (i, b),
                                       'DB %d: 0x%02x' % (i, b), '0x%02x' % b]])
            self.ss_databytebits = []

        elif bitnum > self.last_databit:
            return self.decode_frame_end(can_rx, bitnum)

        return False

    def handle_bit(self, can_rx):
        self.rawbits.append(can_rx)
        self.bits.append(can_rx)

        # Get the index of the current CAN frame bit (without stuff bits).
        bitnum = len(self.bits) - 1

        if self.fd and can_rx:
            if bitnum == 16 and self.frame_type == 'standard' \
                    or bitnum == 35 and self.frame_type == 'extended':
                self.dom_edge_seen(force=True)
                self.set_fast_bitrate()

        if self.is_stuff_bit():
            self.putx([15, [str(can_rx)]])
            self.curbit += 1 # Increase self.curbit (bitnum is not affected).
            return
        else:
            self.putx([17, [str(can_rx)]])

        # Bit 0: Start of frame (SOF) bit
        if bitnum == 0:
            self.ss_packet = self.samplenum
            self.putx([1, ['Start of frame', 'SOF', 'S']])
            if can_rx != 0:
                self.putx([16, ['Start of frame (SOF) must be a dominant bit']])

        # Remember start of ID (see below).
        elif bitnum == 1:
            self.ss_block = self.samplenum

        # Bits 1-11: Identifier (ID[10..0])
        # The bits ID[10..4] must NOT be all recessive.
        #ID1
        elif bitnum == 11:
            # BEWARE! Don't clobber the decoder's .id field which is
            # part of its boiler plate!
            self.ident = bitpack_msb(self.bits[1:])
            self.fullid = self.ident
            s = '%d (0x%x)' % (self.ident, self.ident),
            self.putb([3, ['Identifier: %s' % s, 'ID: %s' % s, '%s' % s]])
            if (self.ident & 0x7f0) == 0x7f0:
                self.putb([16, ['Identifier bits 10..4 must not be all recessive']])

        # RTR or SRR bit, depending on frame type (gets handled later).
        elif bitnum == 12:
            self.ss_bit12 = self.samplenum

        # Bit 13: Identifier extension (IDE) bit
        # Standard frame: recessive , extended frame: dominant
        elif bitnum == 13:
            ide = self.frame_type = 'standard' if can_rx == 0 else 'extended'
            self.putx([6, ['Identifier extension bit: %s frame' % ide,
                           'IDE: %s frame' % ide, '%s' % ide]])

        # Bits 14-X: Frame-type dependent, passed to the resp. handlers.
        elif bitnum >= 14:
            if self.frame_type == 'standard':
                done = self.decode_standard_frame(can_rx, bitnum)
            else:
                done = self.decode_extended_frame(can_rx, bitnum)

            # The handlers return True if a frame ended (EOF).
            if done:
                return

        # After a frame there are 3 intermission bits (recessive).
        # After these bits, the bus is considered free.

        self.curbit += 1

    def decode(self):
        if not self.samplerate:
            raise SamplerateError('Cannot decode without samplerate.')

        while True:
            # State machine.
            if self.state == 'IDLE':
                # Wait for a dominant state (logic 0) on the bus.
                
                (can_rx,) = self.wait({0: 'f'})
                self.sof = self.samplenum
                self.dom_edge_seen(force = True)
                self.state = 'GET BITS'
            elif self.state == 'GET BITS':
                # Wait until we're in the correct bit/sampling position.
                
                pos = self.get_sample_point(self.curbit)
                (can_rx,) = self.wait([{'skip': pos - self.samplenum}, {0: 'f'}])
                if (self.matched & (0b1 << 1)):
                    self.dom_edge_seen()
                if (self.matched & (0b1 << 0)):
                    self.handle_bit(can_rx)
