Communication between 2 PICs over 2 wires

I have 2 atmega644 processors that need to pass data 2 each other. Serial and SPI is not available on one of the processors. So I have 2 free pins on one processor and the other processor is largely unused.

The logic flow is as follows

1. a 4 x 3 numeric keypad to be scanned for keypress on the first processor

2. Each keypress to be sent to the second processor (to be displayed on an LCD screen)

3. When a 7 digit string is available and the OK button is pressed it is sent to a decoding function on the first processor (already written)

4. The function returns a integer between 0 and 3 which should be passed to the second processor.

Tasks assgined to each processor (P1 and P2)

Processor 1

Scan and decode 4 x 3 keypad.

Send 'start sequence' #FF to P2

Send keypad press to P2 (0 - 9 , del ) ('OK' button to be ignored untill 7digits string entered)

Send 'end sequence' #FE to P2

Receive date string from P1

Decode the 7 digit string resulting in an integer (S) between 0-3

Pass '$S$' to P2

Timeout of 10 seconds between keypress to trigger 'end transaction ' #FD;

Processor 2

Interupt to wait for #FF or #FD from P1 on input pin.

if #FF then send incoming digits to display function

wait for 'end sequence' from P2 and return a date string

Wait for $S$ from P1

#FD used to reset sequence and return to 'wait' state.

How this is solved is entirely up to you and this logic flw is only a guidline.

Compétences : Programmation C, Electronique, Microcontrôleur

Voir plus : communication pics, communication pics lcd screen, string programming, spi programming, serial programming, Programming Logic, flw 2, flow x, data flow programming, 0 1 integer programming, communication is, 10 keypad, spi display, serial communication, s pin, numeric, logic x, integer programming, fd, decode data, string integer, timeout function, receive serial data, digit lcd screen, incoming screen

Concernant l'employeur :
( 33 commentaires ) Halmstad, Sweden

N° du projet : #1068112

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Dear m-r datart, We can accomplish your project. For details on PM Redards Bulgar

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Hi datart, Please check your PMB for details. Thanks & Regards, Tushar

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hello, I am ready for this work. I can supply hardware design and prototopy assembly. Best Regards, Adriano Campos

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HI, I can do this, NO PROBLEM AT ALL thank you maurizio stefani

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Hello, please check pm. Regards.

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We are a group of professional freelancer embedded system engineers. We provide research and development services for mechatronics and real-time embedded systems.

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