HardwareSerial modifications

[agalliazzo]

Added the possibility to configure the hardware serial port for 9 bit comunication and added an event (processed like SerialEvent) for a txfinished interrupt (usefull if you're using the serial port with a rs485 transceiver to drive RE/DE line).
I've tested the modifications with an arduino mega2560 and a pic microcontroller as a receiver with Serial1.

for use the txFinished event you should have a function like this:

void transmissionFinishedEvent1(){
doSomething...
}

[alexsandrino]

Hi, very good work! I have try it on mega2560 and It works very well.
You know if is it possible to use it on Arduino Due SAM3X8E ?

Thanks a lot!
Alex

[agalliazzo]

Hi Alex, I leave the development of HardwareSerial... I saw that the
comunity is not so much interested in 9bit serial so I never go ahead in
testing with new versions of arduino... I never read the SAM3X8E datasheet
but maybe the library should work...
Bye
Alessio

2014-04-14 22:34 GMT+02:00 alexsandrino notifications@github.com:

Hi, very good work! I have try it on mega2560 and It works very well.
You know if is it possible to use it on Arduino Due SAM3X8E ?

Thanks a lot!
Alex

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Reply to this email directly or view it on GitHubhttps://github.com//pull/1221#issuecomment-40414666
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Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it.
- Brian W. Kernighan

[matthijskooijman]

IIRC this pullrequest has been discussed on the mailing list, but since it doubles the buffer size even if not using the 9-bit mode, it's unlikely it will be merged. There was also a post about https://github.com/Bouni/Arduino/tree/hardware-serial-9bit, which adds 9-bit support by using two bytes per character, which is probably a better approach.

[bluesign2k]

@alexsandrino having recently spent quite a bit of time going through the SAM3X8E datasheet looking to improve the Due's various serial libraries I can confirm that as it stands, these modifications will not work on the Due. Using 9-bit on the Due is something I'm looking into.

A less resource hungry implementation that I've seen mentioned somewhere could be to use two consecutive bytes in the buffer rather than making the buffer be uint16_t.

[Bouni]

Hi,

As @matthijskooijman mentioned I've created the 9-bit version of the HardwareSerial.
I decided that using 2 bytes of the buffer for the 9-bit case would be a good practice because it doesn't add costs for those users who use the normal < 9-bit modes. But I've only modified the 1.X branch.
If I do the same changes for the 1.5.X branch, would there be a chance to get it merged?

I've just looked at the SAM3X8E datasheet, the UART section [1] does not describe anything about the possible bit modes. But the USART is capable of 5 to 9 bits [2]. So i think i should be able to get the 9-bit changes done for both platforms!

Can anybody with SAM3X8E experience tell me if that UART is just for special purposes!?

[1] USART, page 755
[2] USART, page 775

[bluesign2k]

The UART isn't for special purposes as such, its just that it only supports the more standard setups ie 8-bit and some parity options. The USART module allows for much more flexibility.

FWIW, I submitted a pull request a while ago (#2006) that enabled the use of the extra modes and prepared for 9-bit mode but I never found a way to prevent illegal configs at compile time.

[ArduinoBot]

Can I build this pull request?

[agalliazzo]

Sure but is an old release... You could only replace HardwareSerial.cpp and
HardwareSerial.h in the arduino library folder

Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it.
- Brian W. Kernighan

2014-08-22 13:52 GMT+02:00 ArduinoBot notifications@github.com:

Can I build this pull request?

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Reply to this email directly or view it on GitHub
#1221 (comment).

[ffissore]

@agalliazzo sorry for the comment from arduinobot. we are setting up automated build of all PRs, so that we can provide a downloadable version of the patched IDE

[CrabbyPete]

What happened with this?

[Bouni]

I modified the Hardware serial for 1.0.X and 1.5.X and submitted pull requests for both:

#2291
#2292

But nothing happened since then, which is a little disappointing :(

If you need 9-bit serial for your projects, you can clone my repo and use that:

https://github.com/Bouni/Arduino/tree/ide-1.5.x-hardware-serial-9-bit

[facchinm]

Superseded by #2291