Tiva C Launchpad SLIP – LCD web browsing – Part 2

In this second part, I’m going to resume what I’ve done since the last post.

For the linux box and usbserial adapter I settled on my BeagleBone Black, which already sports many, I really mean many, UARTs. The procedure to enable the UART on the BBB and setup the SLIP interface is below; my BBB is running Debian 7.5.0 with kernel 3.8.13-bone60 (installed on the eMMC) as the debian (unprivileged) user.

  1. Power up the BBB and log in via ssh.
  2. Enable UART1 (pins UART1_TXD:P9_24 and UART1_RXD:P9_26) with this command:
    $ sudo sh -c "echo BB-UART1 >> /sys/devices/bone_capemgr.9/slots"

    This loads the UART1 Device Tree Overlay via the ‘Bone capemanager.

  3. Setup the SLIP interface with these commands:
    $ sudo slattach -p slip -s 115200 /dev/ttyO1 &
    $ sudo ifconfig sl0 pointopoint up

    The former command sets UART1 (which has been loaded as /dev/ttyO1) in SLIP mode at 115200 baud and keeps running in background, presenting us a new network interface called sl0 that the latter command sets up with local IP and remote IP THESE COMMANDS DON’T WORK, READ THIS UPDATE.

This procedure still doesn’t allow the SLIP interface to access Internet, as this is something I have yet to wrap my head around. By the way, I’m actually at a good point in this project, but after realizing that to load Hackaday’s retro/full site I’d have to write at least a TCP and HTTP stack (no, I don’t like uIP for the TCP part), I think I’ll first write a small working UDP/ICMP stack and then I’ll move on to TCP, putting that goal a bit further that I thought.

Test fixture I put up to test SLIP communication

Test fixture I put up to test SLIP communication (hmm, toes)

I did also test the serial line using an usbserial adapter on my main PC connected to UART1, pinging from the BBB (which is the IP i gave to the other end of the SLIP “cable”) and watching on RealTerm for any hex value showing. I even wrote a small C app that loads the hex captured from RealTerm and saved with HxD, and shows (only) the IP header information. You will find everything in a github repo, sooner or later.

Example of my slipanalyzer simple packet dissector on a SSH capture

Example of my slipanalyzer simple packet dissector on a SSH capture

For today, this is it; I am going to start writing something for my Launchpad right now, and will tell you everything when it’s time.



Tags: , , , , , ,

Leave a Comment

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: