Connect two AVR

[kemo0o]

Hey

i am working for some big project and i have Consume all pins

So i want to use another AVR The question that how i can connect them together one Master and The other slave??

 

[dknguyen]

Hey

i am working for some big project and i have Consume all pins

So i want to use another AVR The question that how i can connect them together one Master and The other slave??

It'd be simpler (coding especially) to just use a bigger microcontroller. But to answer your question you connect can their SPI ports together but then you have to deal with all the coding for them to understand each other- something you don't have to do if you just use a bigger chip.

 

[kemo0o]

in my country only 40-pin is available ^_*
So i must use it

 

[penoy_balut]

you can also do multiplexing to save on pins

 

[kemo0o]

you can also do multiplexing to save on pins

its agood idea

 

[Papabravo]

External Latches(74HC374, 74HC259) can be used for outputs. Multiplexers(74HC257) can be used for inputs. Analog switches(74HC4066) can be used for analog inputs. You can also use either type of shift register, PISO or SIPO for inputs and outputs, and you can find peripherals with SPI or I2C interfaces. I guess the schools in your country neglect to mention the basics, which is why only 40 pin chips are available there.

 

[ikalogic]

Hey

i am working for some big project and i have Consume all pins

So i want to use another AVR The question that how i can connect them together one Master and The other slave??

I really encourages you to use the USART. (which is the synchronous UART!) this way you don't have to deal with baude rates, etc, just connect tow micro controllers working at the same frequency, send data bytes from here to there, and build a routine to handle those data bytes.

I built that system with two 89s52's, and it worked perfectly, One of them was the master, and the other handeled all the line following and motor control issues, in the line follower robot (that you know about, since i was in the same university you are in now!! )

 

[Nigel Goodwin]

Really the question is far too vague to answer, specific requirements have specific solutions, and there's no specific information given here.

To give one specific example, you might have a need to scan a multiplexed keypad?, which uses a considerable number of I/O pins, so you could use a separate processor to do the scanning, and a single pin serial connection to the main processor.

 

[kemo0o]

I really encourages you to use the USART. (which is the synchronous UART!) this way you don't have to deal with baude rates, etc, just connect tow micro controllers working at the same frequency, send data bytes from here to there, and build a routine to handle those data bytes.

I built that system with two 89s52's, and it worked perfectly, One of them was the master, and the other handeled all the line following and motor control issues, in the line follower robot (that you know about, since i was in the same university you are in now!! )

Thanks for This answer
i will use it really
when i finish i will told u
thanks for help