second parameter (optional) is the crc's "start" value which is -1 by default for each of the above, so
crc.crc8("foobar") is the same as
crc.crc8("foobar", 0xFF)
depending on requirements, a different crc can be generated using the second parameter, e.g.
crc.crc8("foobar", 0)
added support for generating crc8 crc16 crc32
second parameter (optional) is the crc's "start" value which is -1 by default for each of the above, so
crc.crc8("foobar")
is the same ascrc.crc8("foobar", 0xFF)
depending on requirements, a different crc can be generated using the second parameter, e.g.
crc.crc8("foobar", 0)