$PacketData#checksum PacketData is passed in and this function adds the packet prefix '$',\r
the packet teminating character '#' and the two digit checksum.\r
\r
- If host re-starts sending a packet without ending the previous packet, only the last valid packet is proccessed.\r
+ If host re-starts sending a packet without ending the previous packet, only the last valid packet is processed.\r
(In other words, if received packet is '$12345$12345$123456#checksum', only '$123456#checksum' will be processed.)\r
\r
If an ack '+' is not sent resend the packet\r