Il 31/12/2020 22:31, Martin Gregorie ha scritto:
> On Thu, 31 Dec 2020 21:41:51 +0100, RobertoA wrote:
>
>> Il 30/12/2020 19:31, Martin Gregorie ha scritto:
>>> On Wed, 30 Dec 2020 16:19:56 +0100, RobertoA wrote:
>>>
>>>> The Raspberry4 board has 6 native uart I'm not talking about serial
>>>> ports via usb but uart on the gpio connector of the Raspberry board
>>>> Having to control devices via uart (for example gps receivers,
>>>> electronic scales, etc.) it would be useful to create a device that,
>>>> communicating with the control computer via ethernet, would allow the
>>>> computer to 'see' the virtual com ports, corresponding to the uart of
>>>> the card Raspberry So it will be necessary to program the Raspberry so
>>>> that it has a tcp /
>>>>
>>> Ignore the gpio lines: Just get a standard a USB-serial adapter. Each
>>> supports a single serial line, so get one for each device with a serial
>>> port that you need to connect to the Pi and either plug them directly
>>> into the Pi or, if you run out of USB ports, via a USN connector block.
>>>
>>> The ones I've used have all presented a common interface to Linux:
>>> plugging one in on a Pi automatically creates a new serial device,
>>> /dev/ ttyUSBnn IIRC, that behaves exactly like one of the predefined
>>> serial ports (/dev/ttynn) that are created at boot time on a PC with
>>> builot-in serial ports. This means that any program using the standard
>>> Linux serial port library routines can read and write to anything
>>> connected to your Pi via a USBserial adapter. It can also set the baud
>>> rate, character size, parity and stop bits.
>>>
>>> The last Serial USB adapter I bought came from PicAxe, where they're
>>> used to upload PIC binaries to a PICAXE chip and/or to let the program
>>> you uploaded to the PICAXE chip talk to a program on your Linux box.
>>> They work just fine if that's a Pi too.
>>>
>>> PICAXE http://www.picaxe.com/ sell adaptors for £12.49 (VAT incl) +
>>> postage:
>>>
>>> https://picaxe.com/hardware/cables/picaxe-usb-download-cable/
>>>
>>>
>>> I'm certain they're available elsewhere too, but that's where I bought
>>> the last one I needed.
>>>
>>>
>> Why ignore the uarts provided on the gpio connector?
>
> Because a USB serial adapter is ready to run off the shelf and uses
> standard RS-232 levels, character encoding, parity and stop bits on its
> serial side, which is compatible with most items with serial connections,
> e.g. puck-type GPS receivers.
>
> The ones sold by PICAXE have the USP blug on the body with a serial cable
> terminated by a 3.5mm 3-wire jackplug. Most other converters seem to come
> with a D9 socket (male or female - you choose) on the converter body and
> the USB plug on a short flying lead. Amazon has loads of them in the £7 -
> £15 price range.
>

The rs232 level is not useful to me
I would connect the uart of the Raspberry gpio connector directly to
electronics at the 3v3 level
Furthermore, the USB ports are not sufficient, of the four available,
two remain free (after keyboard and mouse) while the uart devices to
write/read are 6
For this reason I am trying to exploit the uart directly from the gpio
connector

--- SoupGate-Win32 v1.05