Difference between revisions of "I/O USB"

Latest revision as of 22:09, 10 October 2021

Balthazar I/O USB board

IO-board means connectivity with peripheral devices. These can be seen as on-board and out-board. On-board devices include keyboard + trackpad, webcam, and optional audio card. USB is the usual solution for this. Here for the onboard periphery, a simple USB 2.0 hub is enough. The main mini-computer board usually provides a much better hub for 4 downstream USB devices. At this point, this is still mainly USB 2.0. Of course, some type of mass storage/system disk would be needed: microSD – and especially versions of SSD (SATA or PCIe) – directly or via USB adapter. This would benefit a faster USB port – USB3.x (part of the mini-computer system-on-chip) – or PCIe bus.

Our solution for internal hub:

We chose the GL850G (ssop28-pin) four-port USB 2.0 hub chip with additional two pieces of AIC1526-0 dual USB high-side switch – to switch-off/on manually. It is a well-proven design. Hub will be powered via the upstream port – connected to the mini-computer board. Internal USB periphery power demands are predictable = low, so the usual 500mA limit for the hub is ok. The keyboard + touchpad combination is USB1.1 protocol, webcam, and optional audio card are USB2.0.

Internal USB devices can be switched off manually. This helps with the privacy – the microphone and webcam. For external USB devices disabling the USB power line is the same as unplugging the USB device. The "condom" approach with disabling the data lines is a bit better but solves things mostly with USB plugging into public charging stations. The TPS2540 solution is a USB charging current negotiator – with no data lines connected. A dedicated (micro-USB) charging port solves this problem. The already developed Balthazar PSU-charger has this option.

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PCB is ready for a prototype as KiCad files are available at our Github pages.

Those will be regularly updated as schematics and PCBs are continuously improved and optimized.

BalthazarPSU2 + I/O unifying board

Top and bottom views of an integrated I/O hub with USB

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In a top view with the first chip on the left is a Texas Instruments BQ24193 that acts as a buck-boost converter/ battery charger, another chip is a Texas Instruments TPS63020 for an internal power acting as buck-boost converters (for 3.3V and 5V) Onboard is also Diodes Incorporated PAM8403 enabling 3W class-D audio amplifier while Microchip USB2514 is used as a USB 2.0 four-port hub.

For more on schematics, elements, bills of materials visit our Github page.

Go to: 
Keyboard or Power Supply

@@ Line 2: / Line 2: @@
-IO-board basically means connectivity with peripheral devices. These can be seen as on-board and out-board. On-board devices include: keyboard + trackpad, webcam and optional audio-card. USB is the usual solution for this. Here for the on-board periphery a simple usb 2.0 hub is enough. Main mini-computer board usually provides a much better hub for 4 downstream USB devices.
+IO-board means connectivity with peripheral devices. These can be seen as on-board and out-board. On-board devices include keyboard + trackpad, webcam, and optional audio card. USB is the usual solution for this. Here for the onboard periphery, a simple USB 2.0 hub is enough. The main mini-computer board usually provides a much better hub for 4 downstream USB devices.
-At this point this is still mainly USB 2.0. Of course, some type of mass storage / system disk would be needed: microSD – and especially versions of SSD (SATA or PCIe) – directly or via USB adapter.
+At this point, this is still mainly USB 2.0. Of course, some type of mass storage/system disk would be needed: microSD – and especially versions of SSD (SATA or PCIe) – directly or via USB adapter.
-This would benefit a faster usb port – USB3.x (part of the mini-computer system-on-chip) – or PCIE bus.
+This would benefit a faster USB port – USB3.x (part of the mini-computer system-on-chip) – or PCIe bus.
 '''Our solution for internal hub:'''
-We chose the GL850G (ssop28-pin) four-port USB 2.0 hub chip with additional two pieces of  AIC1526-0 dual usb high-side switch – to switch-off/on manually.  It is a well-proven design. Hub will be powered via the upstream port – connected to the mini-computer board. Internal usb periphery power demands are predictable = low, so the usual 500mA limit for the hub is ok. The keyboard + touchpad combination is USB1.1 protocol, webcam and optional audiocard are USB2.0.
+We chose the GL850G (ssop28-pin) four-port USB 2.0 hub chip with additional two pieces of  AIC1526-0 dual USB high-side switch – to switch-off/on manually.  It is a well-proven design. Hub will be powered via the upstream port – connected to the mini-computer board. Internal USB periphery power demands are predictable = low, so the usual 500mA limit for the hub is ok.
+The keyboard + touchpad combination is USB1.1 protocol, webcam, and optional audio card are USB2.0.
 [[File:SchemeUSB.png|thumb|center]]
-Internal USB devices can be switched of manually. This helps with the privacy – the microphone and webcam. For external USB devices disabling the usb power line is the same as unplugging the USB device. The "condom" approach with disabling the data lines is a bit better, but solves things mostly with USB plugging into public charging stations. The TPS2540 solution is USB charging current negotiator – with no datalines connected. A dedicated (micro-USB) charging port solves this problem.
+Internal USB devices can be switched off manually. This helps with the privacy – the microphone and webcam. For external USB devices disabling the USB power line is the same as unplugging the USB device. The "condom" approach with disabling the data lines is a bit better but solves things mostly with USB plugging into public charging stations. The TPS2540 solution is a USB charging current negotiator – with no data lines connected. A dedicated (micro-USB) charging port solves this problem.
+The already developed Balthazar PSU-charger has this option.
+<gallery>
+File:BalthazarIOusb 0.png|thumb|top
+File:BalthazarIOusb 2.png|thumb|side
+File:BalthazarIOusb 1.png|thumb|bottom
+File:Psiousbctop.png|thumb|top
+File:Psiousbcbott.png|thumb|bottom
+</gallery>
+PCB is ready for a prototype as KiCad files are available at our [https://github.com/balthazar-space Github] pages.
+Those will be regularly updated as schematics and PCBs are continuously improved and optimized.
+=== BalthazarPSU2 + I/O unifying board ===
-The already developed Balthazar PSU-charger has this option.
+Top and bottom views of an integrated I/O hub with USB
+<gallery>
+File:BalthazarIO1PSU2.png|thumb|top
+File:BalthazarIO2PSU2.png|thumb|bottom
+</gallery>
+In a top view with the first chip on the left is a Texas Instruments BQ24193 that acts as a buck-boost converter/ battery charger,
+another chip is a Texas Instruments TPS63020 for an internal power acting as buck-boost converters (for 3.3V and 5V)
+Onboard is also Diodes Incorporated PAM8403 enabling 3W class-D audio amplifier while Microchip USB2514 is used as a USB 2.0 four-port hub.
+For more on schematics, elements, bills of materials visit our [https://github.com/balthazar-space/balthazarPSU2 Github] page.
-The job of preventing uncontrolled USB traffic from the external peripheral device which runs its own software system is problematic and should probably be done on the level of USB driver.
+ Go to:
+ [[Keyboard|Keyboard]] or [[Power_Supply|Power Supply]]