UART or USART, which to choose

Karbos

New Member

• Oct 15, 2008

• #1

I have been working on RS-232 communication lately and I am currently at the point of if I should use UART or USART. USART can operate at faster speeds, but UART has more support. Therefore I am quite confused as what to choose. Perhaps any of you could clear up my problem.

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Oct 15, 2008

• #2

Well RS232 uses a UART - so your problem is solved.

I don't see as there's any more support for either?, both are simple, one uses two wires, one uses just one (both plus ground of course).

What are you trying to do?.

 

philba

New Member

• Oct 15, 2008

• #3

A USART is a superset of a UART. If you are asking should you use Synchronous or Asynchronous serial I/O, that's different. Both UART and USART support Async which is what is used by PCs for serial I/O. What specific UART are you looking at and what speeds doesn't it support.

 

Karbos

New Member

• Oct 15, 2008

• #4

To be more specific the PIC I shall be using is a 18F4620. It has the TX and RX pins, but for TX it states:
"Asynchronous serial transmit data (EUSART module)"
and for RX:
"Asynchronous serial receive data input (EUSART module)"

Am I able to still use UART?

 

blueroomelectronics

Well-Known Member

• Oct 15, 2008

• #5

It's an enhanced UART. But it's still a uart.

 

Karbos

New Member

• Oct 15, 2008

• #6

Ok, thanks. I shall use the 18F4620 in UART mode, with both the TX and RX lines. If I am not mistaken, that is all that is needed to use in UART mode correct?

 

blueroomelectronics

Well-Known Member

• Oct 15, 2008

• #7

Yep that's it. Look for USART calculator on these forums or my web site. It'll do the register calculations for you.

 

Karbos

New Member

• Oct 15, 2008

• #8

I have built the ST232CN board with the 9 pin connector. I will finish the board over the course of this weekend.

 

C

cGr

New Member

• Oct 16, 2008

• #9

I didn't understand a thing.If we need Synchronous comunication,which one we will use?

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Oct 16, 2008

• #10

cGr said:

I didn't understand a thing.If we need Synchronous comunication,which one we will use?

Click to expand...

The USART in a PIC can be configured to do either, easy as pie.