Why #use rs232 but not #use uart?

rikotech8 · Joined: 10 Dec 2011 Posts: 376 Location: Sofiq,Bulgariq

Why #use rs232 instead of #use uart?
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PCM programmer · Joined: 06 Sep 2003 Posts: 21708

Probably because historically, when the compiler was first written,
"rs-232" was the most commonly used protocol (by hobbyists and others).
So CCS used the name that most people would easily recognize.

temtronic · Posted: Mon Jun 15, 2015 2:56 pm

also.... 'UART' typically implies a special peripheral either discrete or masked onto the PIC die whereas CCS allows you to create a 'software 'UART' though it's NOT a true UART it will allow you to send/receive serial data aka RS-232.

The use of the term 'RS232' has misled a lot of people over the years, I still think of it as +-12 Volt signalling using 1488/1489 chips...sigh I must be showing my age !

Jay

Ttelmah · Joined: 11 Mar 2010 Posts: 19451

I think 'history' is the key.

When CCS started, the sole purpose of this, was to provide the TTY interface setup for getc/putc. Doing this without a UART (on chips that didn't have one), or with a UART (on chips that did).

It has 'growed and growed', with handling for RS485 direction control etc..

I've often posted that it should be something like '#use async serial', but then it began supporting synchronous modes, so even this wouldn't cover all the options.

The title is just a 'wrapper' and unfortunately is wrong for anyone who understands what 'RS232' involves, but any replacement is also wrong (no UART in many cases, async and synchronous, etc. etc....).

We 'live with it'.

asmboy · Joined: 20 Nov 2007 Posts: 2128 Location: albany ny

temtronic · Posted: Tue Jun 23, 2015 5:25 am

I always thought...

#USE SIO(...)

..would be more appropriate. RS232 to me usually has 1488 drivers and 1489 receiver chips involved !

SIO ,'Serial Input Output' is a 'generic' term without a preconceived idea as to the hardware or software, only that data uses 1 wire instead of 8.

It would fit better with #USE SPI, #USE I2C, etc.

Jay

tinley · Joined: 09 May 2006 Posts: 67

Could be

use 'firmware asynchronous receiver transmitter'?

Ttelmah · Joined: 11 Mar 2010 Posts: 19451

Except as I already pointed out, it does now support synchronous in some cases.

It is a case where the capabilities exceed the name....

ezflyr · Joined: 25 Oct 2010 Posts: 1019 Location: Tewksbury, MA

RF_Developer · Joined: 07 Feb 2011 Posts: 839

temtronic · Posted: Tue Jun 23, 2015 10:14 am

Word to the wise, NEVER use hipowered 'degreaser' on old ASR33s to get rid of the 'gunk'. It'll destroy the 'plastic' pieces like gears in about 9 days !! BTDT.
First profitable PIC project was a 20ma loop to RS232 convertor, yes using the 1488/89 chips.
sigh, the good old dayze....

Jay