How to use 2 or 3 serial communication in PIC?

[emperor81]

Serial communication

Hai... I'm new for PIC... I'm going to use these chip for my prroject... But, the problem is, I need to use either two or three serial communication, and I don't know how...

Cold anyone over there, please help me...

 

[&lucas&]

Re: Serial communication

If you use PIC16 series you must implement a software communications and you can find on the web many implementations. It’s up to you how manage the communication flow.
Of course you can find two hardware USART on PIC18FXX20 series….

 

[sinkplaat]

Re: Serial communication

A software USART can be implimented, but will take a heavy toll on your processing capabilities. I've recently used a MAX3100 spi USART in a project with great success.

All the nitty-gritty timing and formatting is done by the MAX3100 and the microcontroller uses SPI to interface to it. SPI uses very little resources and is easy to impliment. The MAX3100 is a single USART but I think there are others in the range with more than one in a package.

I can supply some C-code if u like.

 

[emperor81]

Re: Serial communication

I'm planning to use PIC16F877A...
But I dont't understand what do u mean by "...implement a software communications..." ?
I tried search through internet,but i couldn't find it.... What word should I use for searching?
Or, did u mean that, it's all depend the way i program it? And about the schematics, how should i do it?

Did anyone know the web page that could help me?
I only found circuit with one serial comm...
I tried to check for PIC 18F, but it seem the same... :?

 

[emperor81]

Serial communication

I would like to, sinkplaat.
Thanks.
Ca u include the schematics?

 

[&lucas&]

Re: Serial communication

You can find on microchip site, application note AN555,
www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en011045

If you want to use PIC18F download datasheet from microchip site,for example PIC18FXX20,
www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1335&dDocName=en010308

 

[jetset]

Re: Serial communication

I'm planning to use PIC16F877A...
But I dont't understand what do u mean by "...implement a software communications..." ?
I tried search through internet,but i couldn't find it.... What word should I use for searching?
Or, did u mean that, it's all depend the way i program it? And about the schematics, how should i do it?

Did anyone know the web page that could help me?
I only found circuit with one serial comm...
I tried to check for PIC 18F, but it seem the same... :?

He means that if the uC you're using doesn't have hardware for serial communications, you have to implement this by software if you know well the format of transmission.

 

[emperor81]

Re: Serial communication

U mean, if the chip have a serial i/o, i can make more than one serial i/o and control it by software (using latch to select the serial port) ?

 

[hill]

Serial communication

You said you want to use F877A, it has hardware USART. So for the time being, just forget about software implementation of it.

 

[emperor81]

Re: Serial communication

So, in that case, I can just use decoder to select which serial port I want to use if i want to use more than one serial port... Thanks...

 

[checkmate]

Re: Serial communication

The PIC you are using has a hardware USART. A hardware USART makes things easier as all you have to do is to initialise it and pump your data to/from a particular register. A software USART is a USART implemented in software, by a process called bit-banging, where you push/read bits out of a GPIO pin according to the serial RS232 protocol. Hence, it is purely software in nature. Software USARTs, being software, give a high overhead on instruction cycles as many cycles are required for a single read/write operation, and hence not recommended. You probably can't have multiple USARTs active at the same time. One thing you could do though is to multiplex/demultiplex the hardware USART pins onto several DB-9 devices.

 

[Humber555]

Re: Serial communication

emperor81 wrote:

Hai... I'm new for PIC... I'm going to use these chip for my prroject... But, the problem is, I need to use either two or three serial communication, and I don't know how...

Cold anyone over there, please help me...

If you are new for PIC it´s not the best idea to start your first project using 2 or 3 serial ports.
Also you didn't tell us if you are going to program in Assembler or another languaje.
I strongly suggest to start with a small model that you can handle fluently hardware + sofware.
Once you get full control, you can add other features, step by step.

Just my opinion,

humber555

.

 

[Humber555]

Re: Serial communication

emperor81 wrote:

Hai... I'm new for PIC... I'm going to use these chip for my prroject... But, the problem is, I need to use either two or three serial communication, and I don't know how...

Cold anyone over there, please help me...

If you are new for PIC it´s not the best idea to start your first project using 2 or 3 serial ports.
Also you didn't tell us if you are going to program in Assembler or another languaje.
I strongly suggest to start with a small model that you can handle fluently hardware + sofware.
Once you get full control, you can add other features, step by step.

Just my opinion,

humber555

.

 

[axl]

Re: Serial communication

Forget about using a software emulated USART unless your MCU has nothing to do else than checking a button and sending a couple of bytes...

Rather than adding an external USART, use a PIC18FXX20 (these family devices have two USARTs built-in)

 

[emperor81]

Serial communication

I'm new to PIC... But, my supervisor looking for two @ three serial communication before he allowed me to proceed with the project... So, I choose to use PIC... Well, I try first....

 

[&lucas&]

Re: Serial communication

Hi, I think you spend too much talking, go to work, we offer you three solution for implementations it up to you and your project requirements to choose one.
I make a schematic for you ...take it only a reference...

 

[feiutm9898]

Re: Serial communication

Does anybody can post the : Serial Port Complete" book??

 

[shahrol_hisham]

Re: Serial communication

this is a note about serial com