[SOLVED] Poly Microcontrollers

[OunaLypse]

Who has ever Designed a system that uses 5 microcontrollers?

I have and is working on proteus, but I have little faith on Hardware implementation, will it work?

 

[alexan_e]

It depends on what you expect each one to do but I wonder what kind of project requires five mcu.

 

[bigdogguru]

An embedded system compromised of five microcontrollers is NOT an extraordinary situation.

A typical midrange automobile has approximately 50 microcontrollers incorporated into its design.

A typical luxury automobile has approximately 100 to 150 microcontroller incorporated into its design.

A ten year old report:

Microcontrollers for the Automobile (2002)


BigDog

 

[OunaLypse]

Hmm! thank you! so what worries me is the number oscillators I had to deploy on the same cct. each chip has it's own oscillator cct.

 

[bigdogguru]

If the MCUs operate at the clock frequency, you typically only need one oscillator.

What specific microcontroller are you utilizing?


BigDog

 

[OunaLypse]

I'm using PIC16F84, I wish to upload the design now, let me find my way through this Forum, I mean how to attach!

 

[bigdogguru]

Use the "Manage Attachments" button in the lower left corner of the Quick Reply box.




BigDog

 

[OunaLypse]

I got it, I did use that but told me invalid file, so now i used a Zip folder! it's done!~

thank you!

 

[alexan_e]

That was what I had in mind when I said "I wonder what kind of project requires five mcu."
You only need one mcu to do your circuit , you can use one shift register 74HC595 to drive the display segments in parallel and multiplex them (light one at a time switching in a fast rate).
You can also use one shift register per display if you wish to drive then constantly.

I think you'll find a tutorial like this useful
**broken link removed**

 

[OunaLypse]

That's the problem, I am actually designing a clock(Time) which is why that method failed, I did think about it!

 

[alexan_e]

What do you mean by that?
Why can't the method I mentioned be used for time?

 

[OunaLypse]

Ooh! thank you i get the concept now, so If i use fast rate I can be able to display many digits for any duration until the proceeding digit(s) updates right?

unfortunately I have little time, because this is my
Design project subject and is due next week So i'll stick to what i have done so far!!!

 

[alexan_e]

Consider it like having two processes, one is the clock counter which is a high priority usually using an interrupt and the second one is the display routine that constantly refreshes the display is a rate about 50-100 times /display to avoid flicker.

 

[OunaLypse]

thank you very much, you really helped

 

[alexan_e]

Here is a video that shows segment multiplexing https://www.youtube.com/watch?v=R9kUadTXpzs&feature=related

My description was for a digit multiplexing like https://www.youtube.com/watch?v=0BEyn-iFdws&feature=related

 

[OunaLypse]

I see thank you, can you forward me the multiplexing method!

 

[alexan_e]

I don't use pic so I can't do much for the code but basically you have to connect all display digit lines in parallel (all A, all B...) to the shift register (74HC595) and four transistors that each controls the common supply of one display.
Depending on the display current you may need to use a device that can provide more current between the shift register and display digit lines, for example ULN2003

suppose that you want to show 1234

turn off everything
send data for 1 to the shift register
turn on display 1
small delay

turn off everything
send data for 2 to the shift register
turn on display 2
small delay

turn off everything
send data for 3 to the shift register
turn on display 3
small delay

turn off everything
send data for 4 to the shift register
turn on display 4
small delay

restart from the first display

- - - Updated - - -

This may help with the shift register operation https://www.edaboard.com/threads/222857/

 

[OunaLypse]

thank again, *** bless you, i will look into that!