Set transmit frequency
Function1:Long press(More than 2s), Select FR or CH mode
(1) FR Mode, LED_SW indicator light on(LED_ SW =1);
(2) CH Mode, LED_SW indicator light off(LED_ SW =0);
Function2:Short press(Less than 2s),Set FR or CH of channel
FR Mode ,Switching group of channel
CH Mode ,Switching index of channel
Notes:10s no operation, the LED2~LED0 loop display FR and CH of current channel.