DRF1278DM

Revision 2.72

May. 2017

2/13

PIN FUNCTIONS

PIN

DIP-A

Function

Description

1

GND

Ground

Ground (0V)

2

VCC

Power

Power supply

3

EN

Input

Enable pin, Low effective

4

RXD

Input

RXD: UART input, TTL level

5

TXD

Output

TXD: UART output, TTL level

6

AUX

Output

Data indication pin for waking up module

7

SET

Input

Control pin, effective in central/node mode

Table 1: DRF1278DM Pin functions

Note:

1. For firmware version < V2.0, SET pin is reserved without special function. For firmware

version >= V2.0, the logic level of SET pin is used to switch between normal speed communication

(or express communication) and breath period communication in central/node mode. In sleep status,

the SET pin should be connected to logic high or floated. If users don't need normal speed

communication, the SET pin also can be connected to logic high or floated to save power.

2. If the module is connected to the microcontroller, it will send a string to microcontroller when it

is powered on

9600 N 8 1 DRF1278X V2.7

The last alphanumeric characters V2.7 indicate the firmware is 2.7. If users connect a USB adapter

DAC02 to computer and run a serial tool such as Advanced Serial Port Monitor, the module also

sends a string to the tool as soon as it is inserted into the USB adapter.

3. In order to configure the parameters, the EN pin should be connected to logic low in any mode.

In standard mode, the EN pin also should be connected to logic low to let modules work normally.

If the EN is connected to logic high in this mode, the RFIC and MCU of the modules will be in

deep sleep and only can be waken up by setting this pin to logic low. In central mode, the EN pin

also needs to be logic low just like in standard mode. In node mode, the module will monitor the

wireless signal at the interval of breath period and close the UART interface to save power when

EN pin is set to logic high. If the module in node mode needs to send data to central module, users

can set the EN to logic low and the node module will enable UART interface to receive data from

microcontroller.