remove T1,T6, replace those to EN signal.
add CmdHelp() to display help info.
put welcome words into a function SayWelcome()
add port module
recode dbgPutCmd(), puts nothing when argscnt is zero.
rm soucre of port operations
replace tab to spaces
add functions SetVTable(), GetVTable(), SetVoltageByVTable(), rename SetVoltage() -> SetVoltageByValue()