Updated state machine with correct name.

The state diagram shows possibility to move back from state 2 to state 1. Do you really want it? If you imagine a key press and the procedure to process it, then you will see that the system stays in state 1 until key press detection and moves to state 2 where the press debounce is processed. During the debounce time we don't want to react to key bouncing signals because it makes whole debouncing process meaningless.

 

The state diagram shows possibility to move back from state 2 to state 1. Do you really want it? If you imagine a key press and the procedure to process it, then you will see that the system stays in state 1 until key press detection and moves to state 2 where the press debounce is processed. During the debounce time we don't want to react to key bouncing signals because it makes whole debouncing process meaningless.

Yes, in the proposed design, you need the path back from state 2 to state 1. State 2 debounces the matrix while the key is held. If the key is successfully debounced, the FSM proceeds to state 3, the terminal 'key closed' state. If the debouncing is not successful, it returns to state 1 to begin again.

There are some holes in this state diagram but those can be filled in as we progress as a learning exercise.

 

There are some holes in this state diagram but those can be filled in as we progress as a learning exercise.

I haven't left any topic yet but I am finding it very difficult. I tried very hard to understand it. For now I want to stop interfacing the matrix keypad. I would like to move to another topic

 

For now I want to stop interfacing the matrix keypad. I would like to move to another topic

As you wish.

 

@JohnInTX

So far we have successfully written and tested various programs for uart, spi and i2c devices on pic development board. I'm pretty sure right now that I can write code for any i2c and spi device.

Now I guess I should go one step further.

I found in google search that most of the recruiters search the profile of the candidate who has mainly knowledge of CAN, RTOS and linux programming, iot. it will not be right to learn all the technology at the same time. Which technique do you think I should learn first?

i think i don't have enough hardware available to learn all these techniques may be i have to buy some other equipment. Suggest if additional hardware needs to be purchased

Please let me know what is your suggestion for this.

 

Which technique do you think I should learn first?

You should learn the technique of being able to define a problem, create a solution then execute that solution to completion including debugging and testing. You have not demonstrated that you can do that. I2C, SPI, CAN, UART, RTOS, and yes, 4x4 matrix.. EVERYTHING that you do in this field is built upon that same skill set. Abandoning the 4x4 matrix when the solution was pretty much complete shows that you have more work to do in the basics.

Starting CAN or anything else will be more and more difficult. You may want to have things to include on your CV but at the entry level, a prospective employer will be interested more in how you approach a problem and construct a solution than a list of things that you have messed around with.

Just my humble opinion.

 

yes, 4x4 matrix.. EVERYTHING that you do in this field is built upon that same skill set. Abandoning the 4x4 matrix when the solution was pretty much complete shows that you have more work to do in the basics.

I get your point, I should start from where I left off. my matric keypad work is still unfinished so i must finish it. I was busy preparing for the university exam for the exam so I didn't have much time. But now i have enough time and i can focus on practical learning.