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USB experts? Question about serial devices, implementing multiple ports on QDX

Hans Summers All Messages By This Member #91119 Hi all So there was some discussion here about implementing a second serial port on QDX. This would allow some configuration and monitoring activities to take place on one serial port connected to a terminal emulator, while another serial port is connected to WSJT-X for CAT control.? Implementing a second serial port using microcontroller UARTs is a relatively straightforward proposition however, less useful than it would be to be able to have TWO serial ports across the USB cable. However, resource constraints mean that it appears difficult, perhaps impossible, to support TWO serial ports on USB - that's why I am asking if there are any USB experts on here.? Details - the serial port is the Communications Device Class Abstract Control Model (CDC ACM). The STM32F401 used has a USB peripheral supporting 4 pairs of endpoints. For non-USB experts... endpoints are like a USB communication channel between the PC and the device. In QDX these are used as follows: 0: USB control endpoint - this is always endpoint zero in any USB system 1: CDC Data in/out endpoint pair 2: CDC Command endpoint 3: Audio in/out endpoint pair The Composite device (thought of like a USB Hub) layer sits above that but does not use up any endpoints itself, it's just a wrapping. Since the STM32F401 has 4 pairs of endpoints and these are all used, it appears that implementation of a second serial port is impossible. But the world is full of tricks. There could be ways. Does anybody know? It is nice to dream that there might be some way to hack around in the code in the lowest layers of USB code and somehow fake something to look like there are more endpoints than there really are?? 73 Hans G0UPL
KEN G4APB All Messages By This Member #91120 Hi Hans,? just an observation…you kinda already have done this on the QLG2 gps module haven’t you? ?a USB serial port and the gps data out (TTL) that I just recently ran a bluetooth serial dongle to. Maybe a bit of external interfacing might get around the requirement? 73 Ken g4apb?
Hans Summers All Messages By This Member #91121 Hello Ken > just an observation…you kinda already have done this on the? > QLG2 gps module haven’t you? ?a USB serial port and the? > gps data out (TTL) that I just recently ran a bluetooth serial? > dongle to. Maybe a bit of external interfacing might get? > around the requirement? Yes, the QLG2 implements a USB <-> Serial converter. Which you can use either for GPS data, or for any other purposes. So a QLG2 could be used as a converter for a QDX additional serial port implemented as a UART. That's a plan B. But it's not as attractive as being able to connect two serial devices to two QDX serial ports over the same existing USB cable we have now.? 73 Hans G0UPL toggle quoted message Show quoted text On Wed, Aug 24, 2022 at 9:25 AM KEN G4APB <lfoofui.nbz42@...> wrote: Hi Hans,? just an observation…you kinda already have done this on the QLG2 gps module haven’t you? ?a USB serial port and the gps data out (TTL) that I just recently ran a bluetooth serial dongle to. Maybe a bit of external interfacing might get around the requirement? 73 Ken g4apb?
Andy All Messages By This Member #91122 开云体育 Two ideas, both software heavy. Stop using CDC and write your own custom protocol. You can then multiplex as many channels of data as you want over a single pipe. You'll need to write a driver for the QDX end and Linux/Windows/Mac that handles the comms and audio as a composite driver and on the host computer split the multiplexed data out and fake the COM ports so application software can see the COM ports and use them. Stay using CDC but again multiplex the data over the signal channel. At the host you'll need to write something that takes data from the CDC COM port and demultiplexes it and then fake the extra COM ports for applications to use. Option 2 sounds easier to me but still quite some work. Andy toggle quoted message Show quoted text From: [email protected] <[email protected]> on behalf of Hans Summers <hans.summers@...> Sent: Tuesday, August 23, 2022 10:48 PM To: [email protected] Notification <[email protected]> Subject: [QRPLabs] USB experts? Question about serial devices, implementing multiple ports on QDX ? Hi all So there was some discussion here about implementing a second serial port on QDX. This would allow some configuration and monitoring activities to take place on one serial port connected to a terminal emulator, while another serial port is connected to WSJT-X for CAT control.? Implementing a second serial port using microcontroller UARTs is a relatively straightforward proposition however, less useful than it would be to be able to have TWO serial ports across the USB cable. However, resource constraints mean that it appears difficult, perhaps impossible, to support TWO serial ports on USB - that's why I am asking if there are any USB experts on here.? Details - the serial port is the Communications Device Class Abstract Control Model (CDC ACM). The STM32F401 used has a USB peripheral supporting 4 pairs of endpoints. For non-USB experts... endpoints are like a USB communication channel between the PC and the device. In QDX these are used as follows: 0: USB control endpoint - this is always endpoint zero in any USB system 1: CDC Data in/out endpoint pair 2: CDC Command endpoint 3: Audio in/out endpoint pair The Composite device (thought of like a USB Hub) layer sits above that but does not use up any endpoints itself, it's just a wrapping. Since the STM32F401 has 4 pairs of endpoints and these are all used, it appears that implementation of a second serial port is impossible. But the world is full of tricks. There could be ways. Does anybody know? It is nice to dream that there might be some way to hack around in the code in the lowest layers of USB code and somehow fake something to look like there are more endpoints than there really are?? 73 Hans G0UPL
Hans Summers All Messages By This Member #91123 Hello Andy Yes, both ideas would work BUT both would stray away from one of the core principles of QDX: which is that I would use existing USB device drivers so that no special software or drivers would be needed on USB for the user to install. I think it would be a non-starter because the disadvantages would outweigh the somewhat tenuous advantages... 73 Hans G0UPL toggle quoted message Show quoted text On Wed, Aug 24, 2022 at 9:55 AM Andy <mm0fmf@...> wrote: Two ideas, both software heavy. Stop using CDC and write your own custom protocol. You can then multiplex as many channels of data as you want over a single pipe. You'll need to write a driver for the QDX end and Linux/Windows/Mac that handles the comms and audio as a composite driver and on the host computer split the multiplexed data out and fake the COM ports so application software can see the COM ports and use them. Stay using CDC but again multiplex the data over the signal channel. At the host you'll need to write something that takes data from the CDC COM port and demultiplexes it and then fake the extra COM ports for applications to use. Option 2 sounds easier to me but still quite some work. Andy From: [email protected] <[email protected]> on behalf of Hans Summers <hans.summers@...> Sent: Tuesday, August 23, 2022 10:48 PM To: [email protected] Notification <[email protected]> Subject: [QRPLabs] USB experts? Question about serial devices, implementing multiple ports on QDX ? Hi all So there was some discussion here about implementing a second serial port on QDX. This would allow some configuration and monitoring activities to take place on one serial port connected to a terminal emulator, while another serial port is connected to WSJT-X for CAT control.? Implementing a second serial port using microcontroller UARTs is a relatively straightforward proposition however, less useful than it would be to be able to have TWO serial ports across the USB cable. However, resource constraints mean that it appears difficult, perhaps impossible, to support TWO serial ports on USB - that's why I am asking if there are any USB experts on here.? Details - the serial port is the Communications Device Class Abstract Control Model (CDC ACM). The STM32F401 used has a USB peripheral supporting 4 pairs of endpoints. For non-USB experts... endpoints are like a USB communication channel between the PC and the device. In QDX these are used as follows: 0: USB control endpoint - this is always endpoint zero in any USB system 1: CDC Data in/out endpoint pair 2: CDC Command endpoint 3: Audio in/out endpoint pair The Composite device (thought of like a USB Hub) layer sits above that but does not use up any endpoints itself, it's just a wrapping. Since the STM32F401 has 4 pairs of endpoints and these are all used, it appears that implementation of a second serial port is impossible. But the world is full of tricks. There could be ways. Does anybody know? It is nice to dream that there might be some way to hack around in the code in the lowest layers of USB code and somehow fake something to look like there are more endpoints than there really are?? 73 Hans G0UPL
Andy All Messages By This Member #91124 开云体育 Indeed. Moving from the standard drivers is a serious move that will open up lots and lots of "opportunities" that you don't want to have to debug and support! It's way of doing what your want, but fraught with issues.? A last resort probably. Andy toggle quoted message Show quoted text From: [email protected] <[email protected]> on behalf of Hans Summers <hans.summers@...> Sent: Wednesday, August 24, 2022 12:14 AM To: [email protected] <[email protected]> Subject: Re: [QRPLabs] USB experts? Question about serial devices, implementing multiple ports on QDX ? Hello Andy Yes, both ideas would work BUT both would stray away from one of the core principles of QDX: which is that I would use existing USB device drivers so that no special software or drivers would be needed on USB for the user to install. I think it would be a non-starter because the disadvantages would outweigh the somewhat tenuous advantages... 73 Hans G0UPL On Wed, Aug 24, 2022 at 9:55 AM Andy <mm0fmf@...> wrote: Two ideas, both software heavy. Stop using CDC and write your own custom protocol. You can then multiplex as many channels of data as you want over a single pipe. You'll need to write a driver for the QDX end and Linux/Windows/Mac that handles the comms and audio as a composite driver and on the host computer split the multiplexed data out and fake the COM ports so application software can see the COM ports and use them. Stay using CDC but again multiplex the data over the signal channel. At the host you'll need to write something that takes data from the CDC COM port and demultiplexes it and then fake the extra COM ports for applications to use. Option 2 sounds easier to me but still quite some work. Andy From: [email protected] <[email protected]> on behalf of Hans Summers <hans.summers@...> Sent: Tuesday, August 23, 2022 10:48 PM To: [email protected] Notification <[email protected]> Subject: [QRPLabs] USB experts? Question about serial devices, implementing multiple ports on QDX ? Hi all So there was some discussion here about implementing a second serial port on QDX. This would allow some configuration and monitoring activities to take place on one serial port connected to a terminal emulator, while another serial port is connected to WSJT-X for CAT control.? Implementing a second serial port using microcontroller UARTs is a relatively straightforward proposition however, less useful than it would be to be able to have TWO serial ports across the USB cable. However, resource constraints mean that it appears difficult, perhaps impossible, to support TWO serial ports on USB - that's why I am asking if there are any USB experts on here.? Details - the serial port is the Communications Device Class Abstract Control Model (CDC ACM). The STM32F401 used has a USB peripheral supporting 4 pairs of endpoints. For non-USB experts... endpoints are like a USB communication channel between the PC and the device. In QDX these are used as follows: 0: USB control endpoint - this is always endpoint zero in any USB system 1: CDC Data in/out endpoint pair 2: CDC Command endpoint 3: Audio in/out endpoint pair The Composite device (thought of like a USB Hub) layer sits above that but does not use up any endpoints itself, it's just a wrapping. Since the STM32F401 has 4 pairs of endpoints and these are all used, it appears that implementation of a second serial port is impossible. But the world is full of tricks. There could be ways. Does anybody know? It is nice to dream that there might be some way to hack around in the code in the lowest layers of USB code and somehow fake something to look like there are more endpoints than there really are?? 73 Hans G0UPL
KEN G4APB All Messages By This Member #91127 You probably know this already but I am learning…. A single USB host controller can allow?up to 127 connected devices. A connected USB hub counts as a USB device address, and every device connected to it goes towards the maximum allowed addresses for that one host controller. A single USB device can allocate up to 32 endpoints. So there must be a way of doing it. 73 Ken g4apb?
Andy All Messages By This Member #91130 开云体育 can allocate up to 32 endpoints The key words are "up to". The STM32F401 in the QDX has many fewer endpoints. Andy From: [email protected] <[email protected]> on behalf of KEN G4APB <lfoofui.nbz42@...> Sent: Wednesday, August 24, 2022 1:58 AM To: [email protected] <[email protected]> Subject: Re: [QRPLabs] USB experts? Question about serial devices, implementing multiple ports on QDX ? You probably know this already but I am learning…. A single USB host controller can allow?up to 127 connected devices. A connected USB hub counts as a USB device address, and every device connected to it goes towards the maximum allowed addresses for that one host controller. A single USB device can allocate up to 32 endpoints. So there must be a way of doing it. 73 Ken g4apb?
William Smith All Messages By This Member #91137 开云体育 What's the purpose of: 2: CDC Command endpoint in this scenario? ?If it's just setting parameters of the data channel, can you set those to some reasonable defaults and use that channel for something else? Just brainstorming! 73, Willie N1JBJ toggle quoted message Show quoted text On Aug 24, 2022, at 1:48 AM, Hans Summers <hans.summers@...> wrote: 0: USB control endpoint - this is always endpoint zero in any USB system 1: CDC Data in/out endpoint pair 2: CDC Command endpoint 3: Audio in/out endpoint pair
Rob Giuliano All Messages By This Member #91144 I am definitely no USB expert, nor am I an STM32 expert. This article doesn't say anything about the "endpoints", but does discuss multiple serial interfaces: might be worth a look. -- Rob KB8RCO
Colin Kaminski All Messages By This Member #91146 I saw an idea on Google. Have the QDX report as a hub with two devices on it? Colin - K6JTH toggle quoted message Show quoted text On Wed, Aug 24, 2022 at 6:37 AM Rob Giuliano via <kb8rco=[email protected]> wrote: I am definitely no USB expert, nor am I an STM32 expert. This article doesn't say anything about the "endpoints", but does discuss multiple serial interfaces: might be worth a look. -- Rob KB8RCO -- Colin Kaminski - K6JTH https://www.qsl.net/k6jth/
Hans Summers All Messages By This Member #91166 Colin, QDX reporting as a "hub" with two USB devices on it is exactly what it does already. The two devices are Audio and Serial. There just isn't, at first sight, space for any more, as far as the hardware resources go. Rob, I've seen the triple Serial to USB thing before. The "Blue pill" uses the STM32F103. For whatever reason, although a considerably less well endowed device than the F401, in almost every way, in the particular area of its USB peripheral endpoint count it is superior, the F103 having 8 endpoints compared to 4 on the F401.? 73 Hans G0UPL http://qrp-labs.com https://www.buymeacoffee.com/g0upl toggle quoted message Show quoted text -------- Original message -------- From: Colin Kaminski <colinskaminski@...> Date: Wed, Aug 24, 2022, 5:03 PM To: [email protected] Subject: Re: [QRPLabs] USB experts? Question about serial devices, implementing multiple ports on QDX I saw an idea on Google. Have the QDX report as a hub with two devices on it? Colin - K6JTH On Wed, Aug 24, 2022 at 6:37 AM Rob Giuliano via <kb8rco=[email protected]> wrote: I am definitely no USB expert, nor am I an STM32 expert. This article doesn't say anything about the "endpoints", but does discuss multiple serial interfaces: might be worth a look. -- Rob KB8RCO -- Colin Kaminski - K6JTH https://www.qsl.net/k6jth/

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