Re: usb to serial help

[Tom Lake]

It won't work. In order to use a USB to RS-232 converter, there has to be a driver on the host system. The Arduino has no such driver.

You'll have to hook the VGA32 to one of the AltairDuino's serial ports that are defined in the AD's configuration program or the serial port on an expansion card.

On Friday, November 4, 2022 at 7:52:22 PM UTC-4 John Galt wrote:

Here is the situation:

I want to connect a VGA32/ESP32 to the Altair Pro using the native USB port from the DUE.

so i can remap Primary from the Geoff to the VGA32.

1) i bought a USB to UART converter

2) i have it wired into my VGA32

3) i have plugged it into my windows 7 machine and have verified it works i have two way communication through terminal and back from the VGA32 ps/2 keyboard.

i plug it into the Altair pro and i get no communication. if i try to access the native port through usb with a ping program i wrote the altair locks up and i have power cycle.

if i plug in my windows 7 machine and connect via windows terminal and run the same ping program i get information from the altair to the pc as normal.

---

round 2

I take the same USB to UART i disconnect it from the VGA32 and connect another UART -> 9db pin  converter with a serial diagnostic tool i get TX and RX lit up as normal

and if i plug my VGA32 to that i get no communication to the altair pro. I tried a null modem converter as well.

i can only seem to get correct serial communication from the Goeff serial port which has no problems talking to the same VGA32.

no issues with the same usb -> uart when going back and forth in windows. no problem with the usb to windows from the altair.

i have a power blocker on the usb, everything is 3.3 volts.

without the power blocker the VGA32 keeps getting powered off the altair pro power supply which i don't want. no error lights come on. used the same power blocker for windows.

what makes the Geoff serial port so special, why can't i get the usb to convert properly?

[Tom Lake]

Of course I mean one of the real serial ports, not the two USB ports on the Arduino itself.

[Walt Perko]

Hi, 

Sounds like a new I/O board for Altair-Duino computers.  Have a choice of the original VT-100 or the ESP32/VGA32 video out.  

or maybe a little board that taps off PIC video signal INPUT, GND and 3.3V to the ESP32 with a 2nd VGA connector on the back of the Altair-Duino?  

.

[da...@hansels.net]

As far as I understand you are trying to connect a device to the Arduino DUE native USB port
that has a serial (RS232) connector on the other end and basically allows you to connect a

RS232/serial device to the native USB port. Is that correct?

This is actually possible but can be tricky to get to work. I have one of the USB host controller boards

from hobbytronics and when using their CDC class firmware for the board I can plug it into the Due Native
port and get serial data out of it. Two caveats:

1) I got my board 5 years ago so I don't know if the version they are selling now still works.
2) When I got my board it did not work at first (well it would receive data but not send). I had to

     work with their technical support to get it to work. They were very helpful and quick to respond.

The firmware for the native USB port on the Arduino DUE only implements the USB CDC client protocol.
If your USB host board does not support that then it won't work.

On Saturday, November 5, 2022 at 2:15:39 PM UTC-4 John Galt wrote:

i was researching it many people have had the same issue over the years.

i wonder why there is no a raspberry pi or Arduino solution where those handle the conversion and you just plug in a serial and a usb and it handles the transfer between the two, many people have asked for that.

i looked up expensive commercial converters for equipment and they all require windows or mac to handle the conversion via a driver.

i have a software solution where i can configure virtual serial ports and i can setup a bridge between a usb and serial device but it defeats the point of just wanting to plug in a stand alone hardware solution. this would involve having my laptop as a go between.(which is where the pi or arduino should be)

[Walt Perko]

Hi, 

You can easily convert from RS-232 to USB/TTL or vice versa using these:  https://www.ebay.com/itm/183310769032  

I've found more than one use for these little modules.  

.

On Saturday, November 5, 2022 at 3:59:48 PM UTC-7 John Galt wrote:

correct. 

is there a difference with using the DUE programming port instead? would that make it easier?

i was trying to locate a VGA32 V1.1 or V1.2 board(they only sell the V1.4 now). the older versions have USB output D+,D- where the newer version only has RS232.

i was hoping this would just have been easy with all the convertors around.

any chance of designing something that would plug into to mini usb and magically give you a 9pin serial :-)

[da...@hansels.net]

I guess I don't quite understand what you are doing with the Geoff Graham terminal. How is it

connected to the Due? I know that the terminal can be plugged into a PC via USB and then output

serial data on its serial connection. Are you saying that it ALSO works when you plug the terminal

into the native USB port on the Due? That would be very surprising. As far as I know the terminal

can only act as a USB device, not as a USB host. The native USB port on the Due is also a USB device.

Plugging two devices into each other can not work. A device always needs to plug into a host.

Note that both the terminal and the Due have USB-B sockets, you'd need to do some cable hacking
to connect the two together.

The board I linked to is a USB host board and contains the firmware/driver necessary to talk to a

USB CDC device (such as both the programming and native port on the Due). It has a USB-A

connector on one end which you can connect to the USB-B connector on the Due. The board

does the conversion between USB and TTL serial. If you need RS232 levels then you can use one

of the boards that Walt linked to to convert the TTL serial to RS232.

So I think what you need is such a host board but I can't guarantee that the one I linked to

will work with the Due. The USB protocol is very complicated and it is hard for USB implementations

on microcontrollers to support every small variant. Much easier to do on a more powerful PC.

That's why it is a hard to just make a small (i.e. microcontroller driven) device that converts USB to serial.

I think the programming port on the Due may be more standard compliant. Both ports use the USB CDC

protocol. I checked my board here and it works with both the native and programming USB port on the Due.

[da...@hansels.net]

One way to get another serial connection you can do the RXL/TXL modification described in the documentation (pages 9-10).

Another possibility: The Due has pins that carry the RX/TX serial signals for the USB programming port connection.
These are digital I/O pins 0/1 on the Due's headers. Internally on the Due board these feed into a serial-to-USB

converter (CDC client) whose USB side is the USB programming port. You can just pick the actual TTL serial signals

off of pins 0/1 before they go to the converter. On older Due boards there was a bug in the wiring that made

it impossible to use these pins, which is why I never mentioned this before. But for more recent boards they work

fine. The Due will mix the data between USB and the 0/1 pins together. Outgoing data is visible on both and

incoming data from both is seen by the Due. I just found that out a couple weeks ago. Only thing to keep in

mind is to disconnect from pin 0/1 if you want to re-program the Due because they could interfere.

On Saturday, November 5, 2022 at 9:38:27 PM UTC-4 John Galt wrote:

just for fun it ordered one of the V2.4 host usb boards

https://www.hobbytronics.co.uk/usb-host-board-v24?search=USB%20Host

with serial CDC firmware on it.

can't hurt

On Saturday, November 5, 2022 at 9:18:57 PM UTC-4 John Galt wrote:

i'll throw this out also:

is it possible to take a spare Graham Terminal I/O from another Altair Pro and have it connected to the native USB port acting as a host so i can have a second 9 pin serial connection, without the SD or its own terminal getting in the way?

On Saturday, November 5, 2022 at 9:17:03 PM UTC-4 John Galt wrote:

yes i need a host of some kind.

do you know of a way that i can connect 2 USB coms together through windows to do what i want?

FYI i tried merging 2 USB coms together via software and i managed to Brick my DUE. i had to reupload the Sketch to the Due as it corrupted it completely.

[Walt Perko]

Hi, 

So is this correct?  

Using the HobbyTronics USB Host (https://www.hobbytronics.co.uk/usb-host-board-v24?search=USB%20Host) I connect Rx & Tx to PINs 1 & 0 on the Arduino DUE, GND and 3.3V or 5V for power and then I can have the Programming Port as a serial RS-232 port to a terminal?  

Which PINs on the Arduino DUE are for the "Native" USB port?  Can I use that to an adapter to connect to a RS-232 terminal too?  

. 

[Tom Lake]

If you connect to pins 0 and 1 then you should only need a TTL-RS-232 converter (See below) and not have to worry about having to deal with a programmable converter.

[da...@hansels.net]

Glad it worked John! Did you end up using the TXL/RXL pins or the 0/1 pins for the new serial port?

Walt: As Tom said if you use the 0/1 (programming port) pins then you can skip the USB host board. For the native port
there are no pins on the Due board. The USB support for the native is integrated into the main processor

so there are no intermediate traces where you can pick up the signal between processor and serial-to-USB converter.

[Walt Perko]

Hi, 

That is what I thought, too many messages cause too much confusion.  

.

[Tom Lake]

You still don't need the host USB board for the RXL/TXL pins. They work just like the 0/1 pins in that they use a TTL serial signal that just

needs converting to RS-232 levels to be useful with terminals. You only need the host board to convert the USB port signals to RS-232 signals.

On Sunday, November 6, 2022 at 9:55:21 AM UTC-5 John Galt wrote:

I used the txl/rxl pins. I still have the host usb board on order and will play with them when they show up.

[Walt Perko]

Hi, 

Now what is the settings in the Configuration Editor?  

Or is it just connect the USB cable to the https://www.hobbytronics.co.uk/usb-host-board-v24 adapter connected to a  TTL to RS-232 https://www.ebay.com/itm/183310769032 adapter to a terminal?  Maybe need a NULL Modem adapter and/or a gender changer in the string.  

.

On Monday, November 14, 2022 at 6:42:53 PM UTC-8 John Galt wrote:

more fun

Here is Walt's serial speech module. its now running off the DUE Native USB port to a serial converter allowing any USB on the altair pro to turn into a 9pin serial if wanted.

little video of it singing.

https://youtu.be/TpseeKELk0w

On Monday, November 14, 2022 at 9:14:46 PM UTC-5 John Galt wrote:

follow up: 

the USB host boards arrived and i hooked them up to the VGA32 and it works perfectly.

i'm going to wire up another serial to usb converter with the host then try out another 9 pin serial device with it.

On Sunday, November 6, 2022 at 4:45:55 PM UTC-5 John Galt wrote:

I should point out. i originally wanted to connect to the USB ports (which would need the host board) david gave the option of using the RXL/TXL which made the most sense because my DUE Programming port is occupied.

the RXL/TXL turned out to be the best solution because in the end i gained a serial port and took nothing away from the usb ports or other serial port.