example.gp

packet examples:

[fixed/calculated/dynamic] packet ["name"] size=<packet_size in bytes> pipe=<pipe_nr>
{
    frame <"name"> [val] type=<type>
    attr(ibute) <"name"> type=<type> default=<value> values=<value1>,<value2>
    size <"name"> type=<type> data_width=<type> exclude=<"attr1">,<"attrN">
    data <"name"> data_size=<number|"attribute"> exclude=<"attr1">,<"attrN"> type=<type> data_width=<type> escape=<esc> escape_values=<e1>,<eN> escape_op=<func> escape_param=<param>
    crc <"name"> [method] start=<"start_attribute"> end=<"end_attribute"> exclude=<"attr1">,<"attrN"> type=<type>

    NI: timestamp <"timestamp"> type=<type> format=<unix_ts_s|counter|...>
    NI: sequence <"seq"> type=<type>
}

fixed packet "simple_packet" size=0x10
{
    frame "id" 0xDE /* type uint8 */
    data /* type uint8 */
}

dynamic packet "serial_p"
{
    frame "start" 0x7E

    attr "protocol"
    attr "sequence_nr"
    attr "packet_format"
    data escape=0x7D escape_values=0x7D,0x7E escape_op=xor escape_param=0x20
    crc crc16

    frame "stop" 0x7E
}

dynamic packet "serial"
{
    frame "start" 0x1
    data
    frame "stop" 0x2
}

calculated packet "modbus_rtu_request"
{
    attribute "slave_address"
    attribute "function_code" values=0x1,0x2,0x3
    attribute "starting_address" type=uint16
    attribute "nr_address" type=uint16
    crc crc16 start="slave_address" end="nr_address" type=uint16
}

calculated packet "modbus_rtu_response"
{
    attribute "slave_address"
    attribute "function_code" values=0x1,0x2,0x3
    size "byte_count"
    data type=uint16
    crc crc16 start="slave_address" end="data" type=uint16
}

calculated packet "udp"
{
    attribute "source" type=uint16
    attribute "destination" type=uint16
    size "length" type=uint16
    crc "checksum" crc16 type=uint16
    data exclude="source","destination","length","checksum"
}

types:
bit
char
uint2 -> uint32
int2 -> int32
float
double

crc methods
crc8
crc16
callback