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8-Bit Breadboard Registers (Using D-FlipFlops)

Discussion in 'Microcontrollers, Programming and IoT' started by Balakumaran, Dec 20, 2017.

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  1. Balakumaran


    Dec 20, 2017
    I started to build by 8-bit breadboard computer from scratch. I first built the clock which was successful. Later, when I moved onto the register part, I was not able to be successful. I have went through the circuit couple of times and it looks like the wiring is correct. The "Load" signal which takes 8-bit value from the bus to the register is the one doing the problem and the "Enable" works perfectly as of now.
    I am attaching a picture of the circuit and would love if you could point out any problems and ask me any related questions...
    I am following this youtuber as my guidance to this project :
    The register which he had built is :
    Also, I have done the exact same built that he has done.
    I am using the SN74LS245N as my buffer and my 4-bit D Type Flip-Flop is HD74LS173AN.

    If you look over my model of the register, you will notice 3 jumper wires. The top right(yellow) is the load signal.(tied to power unless I want to use it because these are inverted signals). next to it(dark blue) is the clear signal for both the flip flop's... the bottom left(yellow) is the enable signal(same principle as the load signal but this time it outputs data back to the bus).

    Okay , from my point of view the wiring is perfect. I have checked them time and again. I am running these connections on an ideal 5V Supply.The power rails are also connected correctly.

    Here is a video taken showcasing that when the buses are all zeroes, the register takes in all zeroes when load is active. The enable is also working perfectly.

    Video 1 :

    Now, here is the problem when i try to change the values of the bus and then trying to load them onto my registers.

    Video 2 :

    Clearly , the first two led's should have gone off and the others must have been the same but all returned back to zero.

    Thank You.

    IMG_20171220_093053.jpg IMG_20171220_094455.jpg IMG_20171220_094502.jpg IMG_20171220_094508.jpg
    Last edited: Dec 20, 2017
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