Serial communication is still an essential part of our embedded world. generally we utilize a 3 cable configuration (RX TX as well as GROUND) as well as hope that whatever goes according to plan. though this works for many experimenters, in some cases its not the most perfect situation.  This is where [simmonmt’s] handiwork is available in adding hardware handshaking to a AVR.

The hardware configuration is quite typical, an Atmega644 sits on one end of the connection, passes with a SP3232EB level shifter as well as out to a PC. 5 lines are used, once again one for RX, TX as well as GROUND, however likewise RTS as well as CTS. When the PC is prepared to transmit data it inverts the line (normally held high), the micro controller notices this it pulls CTS low as well as transmission can commence whenever it darn well feels like it. Handy!