MOVING DISPLAYI have implemented a moving display using eight 16 segment displays.It has two modes-Moving display mode and freeze mode with static character with the latest character entered.
(1) - It has been implemented using two arrays each consisting of 8 seven bit d flip-flops.First array is used for storing latest 8 characters entered in keyboard.It is not moving.First d flip-flop of it is connected with the output of keyboard then input of other flip-flops is the output of previous d flip-flop. In this way latest 8 characters are stored in d flip-flops.
(2) - Then we used another array of 8 d flip-flops each of 7 bits.We use binary counter whose output is 0 after certain period of time.Then enable of these d flip-flops is connected with output of OR gate whose inputs are nor of individual bits of output of counter and available of keyboard. In this way enable of d flip-flop is set to 1 when either counter is 1 or available is 1.
(3)-Now we use eight 2:1 multiplexers whose control pin is used for controlling freeze mode.When freeze mode is on then output of multiplexer is output of d flip-flop of 1st array.And when freeze mode is off then output of multiplexer is output of d flip-flop of 2nd array which is moving.
(4)-Output of multiplexer is connected with 16 bit converter module which converts the 7 bit asqii input to 16 bit which is then connected with 16 segment display.