Serial input-Parallel output shift register Using logic IC's (74164, counter,...)

Thread Starter

Albert Luna

Joined Nov 2, 2020
4
Hello, I am trying to make a Serial-in Parallel-out shift Register to be controlled by my PC with logic gates and a 74164, 74193, 555 timer. I am programming it through visual basic and I have no problem making the serial communication, I even made a chat (in a prior application) with it and the data is sent correctly but I'm having some issues with receiving the data and keeping it with the logic. The idea is being able to control the data I output to then control a stepper motor or anything else.Screenshot_1.png

This is the circuit I have developed so far, the 555 timer has 10,200 hz frequency the serial communication is 9600 bauds, 8 data bits, 1 start bit, 1 stop bit, the counter is going to stop at 9 and the clock is going to be activated when a 0 logic so it is starting when the start bit arrives. I have a NAND flip flop to store when to start and it is going to be deactivated when the counter reaches 9, the problem is it is really bugged and I am not sure why it is, when I send any data the 74164 displays 127 or 63 in decimal (0111 1111 and 0011 1111 respectively) and I would like to see if you could give me some hint on it. I did the simulation using a 1hz 555 timer and changing the values by myself and it stopped after the nine bits that is why I would like to see what do you think is going wrong on the circuit. I have not been given a prior circuit to work with but I have used all these IC's (NAND memory, 555 oscillator, 74193 counter) except for the 74164 but I had done a shift register using 74174 so you have an idea of my background regarding digital electronics. The assignement says ¨Create a serial to parallel converter using digital electronics knowledge". Thank you for reading!
 

ericgibbs

Joined Jan 29, 2010
12,456
The assignment says ¨Create a serial to parallel converter using digital electronics knowledge
Hi Albert,
The assignment question is not asking for a Parallel to RS232 Serial type Baud conversion, with Start/Stop Bits.???
Is there any reason that you have chosen to do it this way.?

E
 

Thread Starter

Albert Luna

Joined Nov 2, 2020
4
Hi Albert,
The assignment question is not asking for a Parallel to RS232 Serial type Baud conversion, with Start/Stop Bits.???
Is there any reason that you have chosen to do it this way.?

E
Well I only need to make the serial to parallel conversion the baud rate and start/stop bits are not a requirement I just mentioned just to give you the whole picture (i need start and stop bits and the baud rate could be different but 9600 is the standard)
 

Thread Starter

Albert Luna

Joined Nov 2, 2020
4
The RS-232 in the simulator is ttl compatible, that is something I can get around with an IC the trouble is getting the data right
 
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