Datasheet

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Do I need CTS and RTS on my UART based Bluefruit LE Module?

Using CTS and RTS isn't strictly necessary when using HW serial, but they should both be used with SW serial, or any

time that a lot of data is being transmitted.

The reason behind the need for CTS and RTS is that the UART block on the nRF51822 isn't very robust, and early

versions of the chip had an extremely small FIFO meaning that the UART peripheral was quickly overwhelmed.

Using CTS and RTS significantly improves the reliability of the UART connection since these two pins tell the device

on the other end when they need to wait while the existing buffered data is processed.

To enable CTS and RTS support, go into the BluefruitConfig.h file in your sketch folder and simply assign an

appropriate pin to the macros dedicated to those functions (they may be set to -1 if they aren't currently being used).

Enabling both of these pins should solve any data reliability issues you are having with large commands, or when

transmitting a number of commands in a row.