Using only Rx pin to receive data from HC 05 and attiny85 (Arduino IDE) I was building a Bluetooth car with attiny85 (Arduino IDE) and HC05 bluetooth module. I need 4 IO pins to control the car. Since attiny have only 5vIO's, I am left with only 1 pin to connect to HC05. I would only be receiving data from HC05. So, I want to use that leftover pin as RxD to receive data.


#include //the software serial library
#define RxD 4

SoftwareSerial blueToothSerial(RxD);


But when I do this It gives the following error


No matching function for call to 'SoftwareSerial::SoftwareSerial(int)'

Though it works fine, when I also define a TxD pin. But I want to use only one pin (RxD). Please help.
I suggest you get rid of SoftwareSerial and use instead this Simple
ATtiny USI UART. This is a driver
for a receive-only UART that uses the USI port of the ATtiny85. It is
superior to a software-only UART as it makes good use of the hardware,
leaving more time for the CPU to do more useful things (or sleep and
save battery). Also, unlike SoftwareSerial, it does not need to block
interrupts for long periods, which is a good thing.