Just a few words about the serial connection on the CubieBoard. I have bought my CubieBoard during the indiegogo campaign, and I have bought the Rich Package. This Rich Package also includes a serial cable. This serial cable is an USB to 3.3 Volt UART, which is based upon the pl2303 chip. It has four connectors, Rx, Tx, Ground and 5 Volt.
The red cable is a 5 Volt power supply. Since the I/O lines on the CubieBoard are 3.3 Volt, this should not be connected. Besides, the Vcc pin on the serial connected is a power source, not a power input. So, when using a pl2303, the Vcc should not be connected.
If you’ve read my previous post, you see the problem I’ve encountered: when there was already a USB serial device inserted, the device got a different device name. /dev/ttyUSB0 /dev/ttyUSB1 etc, depending on the sequence they were plugged in, or, at boot time, the port in which they are plugged. So, for this reason, I would like to use real RS-232 ports in stead of those USB UART devices.
My BeagleBoard got an R-S232 port, so I just plug in a nullmodem cable and that’s it. On the CubieBoard, as mentioned before, the signal levels are 3.3 Volt. A MAX3232 based board can be used to convert the signal levels. I’ve bought such a board at dealextreme. When we use this, we will need to connect the Vcc line.
We connect the Vcc on the CubieBoard to the Vcc on the MAX3232 board, the Ground to the Ground, but the Tx and Rx we have to swap. Tx is transmit and Rx is receive. But what the Cubieboard sends is what the RS232 port on my computer will receive, vice versa.
The colours you see in these pictures are no standard colours whatsoever. I just have these wires for general purpose. From what I have read on various places on the internet, the connectors are called dupont connectors. I never knew they were called like that. (Actually, I have no clue how an native English speaking person would pronounce that… it *looks* French to me)
Anyhow, mentioning I/O Voltages, I would like to add, the CubieBoard and Raspberry Pi use 3,3 Volt I/O, but the BeagleBoard uses 1.8 Volt I/O. Keep this in mind when interfacing hardware. Different voltage on the BeagleBoard!
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So i can use any serial device with my Cubieboard using the deal extreme item? I have a serial Z-wave interface, and want to use it with my cubie.
I am not familiar with Z-wave.
The TTL to RS-232 converter is basically just a MAX3232 on a PCB. So, what it does it convert a 5 or 3.3 volt serial interface to RS-232 levels. If the serial interface you’re planning to use uses RS-232 levels its suitable.
Please keep in mind many serial devices not intended for the consumer marked use 5/3.3/1.8 volt in stead of RS-232 levels for their maintenance port. Industrial devices might a different standard such as RS-485.
Morning to every one,
My problem is that , i bought a cubieboard which comes with a PL2303 but on the card i see only USB to UART entry for that PL and 4 pins for RS232. So, what i want to know is how to connect my cable(PL) to be used as USB to Serial converter when i connect it to my PC. For now, i don’t see the utility of that cable as when i plugin to my computer and run minicom, I see any thing displayed from my cubieboard.
Thank you for your help.
If you don’t see anything, or just garbage, on the serial connection, you’ve set the incorrect speed settings.
The connection used by the CubieBoard uses
I am not familiar with minicom. I have been using Putty myself. When Putty starts, you can select a serial connection, enter port and speed. The other settings are in a different tab. The flow control is set by default to “XON/XOFF”, so if can verify you have no flow control configured. I hope that solves the problem.
Hi Andre,
first i thank you for your reply.
I used the settings you give here. And I’m familiar with Putty soo. I tried Putty with these settings but I can’t see no thing on PC screen.
I read about using an serial cable, connecting by cross-connecting RS232 cables on cubieboard.
But, as i have an USB to UART cable, that I use also to put firmware on CB in FEL mode, i thing i can use it also as serial(USB to Serial converter).
So, as I can’t, I wanna know if i must buy an other cable, if that PL 2303 is not a serial cable.
Thank you again for your help.
I have been using both the USB serial cable, supplied with my cubieboard, shown in the first picture, as the rs232 converter to get a serial connection to the cubieboard. So I believe the cable is of the correct type. Can you verify the cable is functioning properly using another device?
But I must say, my cubieboard, from the indiegogo campaign, has stopped working a few months ago. I have been unable to get anything out of it again. So, perhaps you’re experiencing the same problem, I haven’t been able to fix. I assume this is a hardware issue.
Hi Andre,
I don’t know what is the problem with this cable because when i plugin it on my Computer ( Ubuntu 13.10 , kernel 3.11, KDE ) i get this message:
whith dmesg cmd : [ 563.555693] usb 5-2: pl2303 converter now attached to ttyUSB0
and this with lsusb :
Bus 005 Device 005: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port
And when i plugin it on Windows 7 ( with putty ) , it shows ùe that it installed the driver on COM4. So, in putty i put COM4, 115200 , 8N1 , i tried the same on Linux (putty and minicom).
As I see, the cable is detected by 2 softs( putty and minicom) because when i pull it down, i get error mesg on these softs. This issu run me crazy As I can’t get network to these card to connect via ssh or telnet.u know how to fix ethernet problem on these card? I tried as mentioned on cubie website but no thing goes right.
Thank you for your help.
Do yo
The problem with Ethernet on the CubieBoard is the fact it does not have a MAC address, therefore it generates a random MAC address on boot time. So it gets a different IP address from the DHCP server each time it boots. I have described how to configure a fixed mac address by modifying the fex file in this article.
this UART pinout is for tty0 ?
It’s for the serial interface, so that will be /dev/ttyS0. But some ARM Boards use different naming, not sure what the Cubie did, and I can’t check as it died.