I'm not clear how this works. Because if I change the baud rate it definitely stops any communication between the laptop and the Arduino so baud rate must have some meaning in this case. I also tried using a python program I wrote and got the same behaviour of working up to 19200 then stopping so I don't think it's an issue with Pure Data. Maybe a cable issue?
Note that Arduino is usually (or always?) connected through an USB device which emulates a serial device (hence the comport).
In this case the baud rate has no meaning (the baud rate is only used by physical UARTs).
Le jeu. 26 juin 2025 à 00:06, Antoine Rousseau antoine@metalu.net a écrit :
With the latest comport 1.3 (available on Deken) you can set the baud rate up to 4000000, if your system allows it. See https://git.iem.at/pd/comport
Le mer. 25 juin 2025 à 22:53, Alexandros Drymonitis adrcki@gmail.com a écrit :
How did you find such a limitation? You can use it with a 115,200 baud rate just fine on any OS (including Linux).
On 6/25/25 23:50, Jim Ruxton wrote:
I'm using the comport object to speak to an Arduino. I'm finding the fastest baud rate I could use was 19200. I'm on Linux. Would anyone know if this is a limitation of the object in Linux or if there is something else going on. I'd like to send data faster if possible.
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I'm almost sure that the physical data transfer in the USB cable doesn't depend on the baudrate setting. This setting is just a parameter that the USB device can use the way it wants.
In the case the device implements a physical UART, then the setting controls the UART baudrate.
In other cases it can be used for smth else. For instance, the Raspberry pi Pico interprets a predefined baudrate value as a command to switch to bootloader.
Btw: what is your actual Arduino board?
Le ven. 27 juin 2025 à 02:51, Jim Ruxton jim.ruxton@gmail.com a écrit :
I'm not clear how this works. Because if I change the baud rate it definitely stops any communication between the laptop and the Arduino so baud rate must have some meaning in this case. I also tried using a python program I wrote and got the same behaviour of working up to 19200 then stopping so I don't think it's an issue with Pure Data. Maybe a cable issue?
Note that Arduino is usually (or always?) connected through an USB device which emulates a serial device (hence the comport).
In this case the baud rate has no meaning (the baud rate is only used by physical UARTs).
Le jeu. 26 juin 2025 à 00:06, Antoine Rousseau antoine@metalu.net a écrit :
With the latest comport 1.3 (available on Deken) you can set the baud rate up to 4000000, if your system allows it. See https://git.iem.at/pd/comport
Le mer. 25 juin 2025 à 22:53, Alexandros Drymonitis adrcki@gmail.com
a
écrit :
How did you find such a limitation? You can use it with a 115,200 baud rate just fine on any OS (including Linux).
On 6/25/25 23:50, Jim Ruxton wrote:
I'm using the comport object to speak to an Arduino. I'm finding the fastest baud rate I could use was 19200. I'm on Linux. Would anyone know if this is a limitation of the object in Linux or if there is something else going on. I'd like to send data faster if possible.
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To double-check, are you sure the problem is not in the Arduino sketch? Python exhibiting the same behavior tips to that IMO. A quick search yields a similar issue due to using an int for larger baud values:
https://arduino.stackexchange.com/questions/67568/serial-port-fails-with-spe...
On Jun 27, 2025, at 2:51 AM, Jim Ruxton jim.ruxton@gmail.com wrote:
I'm not clear how this works. Because if I change the baud rate it definitely stops any communication between the laptop and the Arduino so baud rate must have some meaning in this case. I also tried using a python program I wrote and got the same behaviour of working up to 19200 then stopping so I don't think it's an issue with Pure Data. Maybe a cable issue?
Note that Arduino is usually (or always?) connected through an USB device which emulates a serial device (hence the comport).
In this case the baud rate has no meaning (the baud rate is only used by physical UARTs).
Le jeu. 26 juin 2025 à 00:06, Antoine Rousseau <antoine@metalu.net mailto:antoine@metalu.net> a écrit :
With the latest comport 1.3 (available on Deken) you can set the baud rate up to 4000000, if your system allows it. See https://git.iem.at/pd/comport
Le mer. 25 juin 2025 à 22:53, Alexandros Drymonitis <adrcki@gmail.com mailto:adrcki@gmail.com> a écrit :
How did you find such a limitation? You can use it with a 115,200 baud rate just fine on any OS (including Linux).
On 6/25/25 23:50, Jim Ruxton wrote:
I'm using the comport object to speak to an Arduino. I'm finding the fastest baud rate I could use was 19200. I'm on Linux. Would anyone know if this is a limitation of the object in Linux or if there is something else going on. I'd like to send data faster if possible.
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A guess:
If there is an USB-Chip like the CH240 on the board which communicates with the arduino uC, it is important which baudrate you use between the chip and arduino, therefore you have to set the baudrate in the arduino the same as in the comport using:
Serial.begin(baudrate).
So set the same in the Arduino sketch and comport like
Serial.begin(115200)
mfg winfried
Am Freitag, 27. Juni 2025, 10:00:58 CEST schrieb Dan Wilcox:
To double-check, are you sure the problem is not in the Arduino sketch? Python exhibiting the same behavior tips to that IMO. A quick search yields a similar issue due to using an int for larger baud values:
https://arduino.stackexchange.com/questions/67568/serial-port-fails-with-spe eds-greater-than-19200
On Jun 27, 2025, at 2:51 AM, Jim Ruxton jim.ruxton@gmail.com wrote:
I'm not clear how this works. Because if I change the baud rate it definitely stops any communication between the laptop and the Arduino so baud rate must have some meaning in this case. I also tried using a python program I wrote and got the same behaviour of working up to 19200 then stopping so I don't think it's an issue with Pure Data. Maybe a cable issue?>
Note that Arduino is usually (or always?) connected through an USB device which emulates a serial device (hence the comport).
In this case the baud rate has no meaning (the baud rate is only used by physical UARTs).
Le jeu. 26 juin 2025 à 00:06, Antoine Rousseau <antoine@metalu.net mailto:antoine@metalu.net> a>> écrit :
With the latest comport 1.3 (available on Deken) you can set the baud rate up to 4000000, if your system allows it. See https://git.iem.at/pd/comport
Le mer. 25 juin 2025 à 22:53, Alexandros Drymonitis <adrcki@gmail.com mailto:adrcki@gmail.com> a>> > écrit :
How did you find such a limitation? You can use it with a 115,200 baud rate just fine on any OS (including Linux).
On 6/25/25 23:50, Jim Ruxton wrote:
I'm using the comport object to speak to an Arduino. I'm finding the fastest baud rate I could use was 19200. I'm on Linux. Would anyone know if this is a limitation of the object in Linux or if there is something else going on. I'd like to send data faster if possible.
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https://lists.iem.at/hyperkitty/list/pd-list@lists.iem.at/message/DHY4 DX545CKEKBHN7OPOYUJHKWDTPRKI/>> >>
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