DragonBoard 410c Serial Port


#1

How many serial ports of dragonboard? I need 6 port serial port, what dragonboard support it? Thank you.


#2

Assume you mean UART.

See Section 4.14 UART in the document below:
https://github.com/96boards/documentation/raw/master/dragonboard410c/HardwareManual_DragonBoard.pdf

You can get up to two at most. Six is a bit of a stretch.
There’s only 1 model of the dragonboard so far, that’s the 410c. There are no other models.


#3

I think that in conjunction with his previous wording in the hikey forum, we may be able to assume that he meant “coms” as reference to that old term “com port”, which is RS-232, whereas the UART on these boards operate at logic level, so the answer would be that without conversion circuitry (such as a MAX232), there are no ports meeting the specifications he is looking for. Also, its not entirely correct that there is only one dragonboard. True that there is only one 96boards dragonboard, but there are dragonboards from before 96boards. Intrinsyc made a dragonboard 800 and 810.

edha: In theory, you could add a large number of RS-232 ports to the board through the use of USB-to-RS232 adapters, such as those utilizing ftdi or pl2303. Just make sure that they match up with the devices you are trying to connect with, since these devices are available in TTL, RS-232, and RS-422 version. Maybe one of these FTDI modules;
http://www.ftdichip.com/Products/Modules/USBRSxxx.htm look at the USB-COM232-PLUS4 module, it takes a single USB and splits off FOUR RS-232 ports.

But be aware that the Dragonboard 410c only actually has ONE USB2.0 port. The others are provided through a switch and a hub, so don’t go too crazy with adding on tons of USB devices.


#4

All, thank you for that information.

I see, FTDI converter is very useful when the limited availability of serial ports on the system. The problem, Dragonboard 410C has only one USB 2.0 host, it means, I can’t use more than one converter.

I am a newbie for android environment. I want use the android to monitor the activities of dispenser pump at the gas station. For this purpose, I need a lot of serial port for communicating with a pump (RS485 / RS422 / current-loop), the printer (rs232), RFID (rs232), payment gateway (rs232). I am using WiFi to communicate with the local server (PC).


#5

I think what you are really looking for is a serial port hub. something like this: http://www.comtrol.com/rocketport-multi-port-serial-cards/rocketport-smpte/rocketport-usb-serial-hubs/rocketport-usb-serial-hub-ii-4port You can plug two of these devices into the two USB Type-A ports on the 410c to get yourself 8 serial ports.

I looked at the current consumption of the Rocketport hubs (325mA each) and this is well within the current supply capabilities of the 410C USB Type-A ports.

These particular serial port hubs plug into the two USB Type=A ports and will provide eight RS-232 level serial ports. You will then need a RS-232 to RS-485 converter for the pump. Something like this: http://www.amazon.com/RS232-Communication-Converter-Adapter-Terminal/dp/B005FOOVLA

I haven’t tried any serial port hub devices with the 410c so I can’t tell you if the necessary drivers are compiled into the kernel or not. Please try it and let us know if the device shows up as a number of /dev/ttyXX devices or not.

Full disclosure: I am an employee of Qualcomm Canada, any opinions I may have expressed in this or any other post are my own and may not reflect the opinions of my employer.


#6

You know what a USB hub is, right? Its like a splitter for USB, which allows you to plug as many USB devices into a SINGLE port as you would like. The only limitation on this is that the combined peak data transfer rate does not exceed the capacity of a USB 2.0 port. The effective throughput possible on a USB 2.0 port is 35 MB per second. To put that into perspective, with the best UART for RS-232, your maximum throughput will be around 460 kilo-bits (not bytes) per second. That means that the USB 2.0 port is roughly 609 TIMES as fast as the best RS-232. So, add in some overhead for the hubs themselves, and you should be fine running up to around THREE HUNDRED RS-232 connections.

Also, DB410c already has a USB hub built in, which is why it actually has TWO USB host plugs, and a third hidden in the high speed i/o interface. Its the apq8016 itself that only has one USB port.


#7

ljking: those things you linked to have roughly the same internals as the boards I already suggested to him, but with a whole lot of added plastic casing around them.

As far as drivers for the hub… it certainly does have those enabled and compiled in already, otherwise the built-in hub wouldn’t work.


#8

@All, I understand now. I need “USB hub module” and “USB to RS232/RS422/RS485/CurrentLoop Converter”.

Can someone recommended to me, where I get “FTDI USB hub module” which suitable for Dragonboard 410C?

Do I need to install the “FTDI USB hub driver” in the Dragonboard 410C later? Or just plug and play?

Thank You.