Gor
Posts: 9
Joined: Tue Jan 12, 2016 4:44 pm

Question about: Touch screen + breadboard and safety rules.

Tue Jan 12, 2016 5:59 pm

I am waiting to get 4 inch Touch Screen TFT LCD Makibes.
http://www.geekbuying.com/item/4-inch-T ... 40088.html

You can see interface description on provided page.

I have question about:

3, 5, 7, 8, 10, 12, 13, 15, 16 NC NC

Does NC mean not used or what is it?

Also this screen <del>is not so handy to use free pins.</del> Actually it does cover only first 26 pins only. Will see what I can do with it.
I am thinking to connect screen via breadboard.
I understand general idea how to do so, but I have a big chance to mess it up and even destroy or damage Pi or screen by mistake.

Any suggestions to avoid it, except obvious one (like do not attach to breadboard while PI is on ) ?
Attachments
Screen Shot 2016-01-12 at 12.57.54 PM.png
Interface description
Screen Shot 2016-01-12 at 12.57.54 PM.png (57.9 KiB) Viewed 1171 times
Last edited by Gor on Wed Jan 13, 2016 2:12 am, edited 1 time in total.

Gor
Posts: 9
Joined: Tue Jan 12, 2016 4:44 pm

Re: Question about: Touch screen + breadboard and safety rul

Wed Jan 13, 2016 2:11 am

I am a little bit stuck here, because DVD provided image does not properly start screen so extra work need to be done on configuration and I don't have HDMI screen (I don't have tv or monitor home).

Trying to play around with cmdline.txt file to init network by default (ip=192.168.0.2 option)

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Burngate
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Re: Question about: Touch screen + breadboard and safety rul

Wed Jan 13, 2016 11:00 am

NC does indeed (normally) mean Not Connected.

From what I can see, they designed it to just slot onto the Pi.
However, for convenience, you can use a breadboard - that's what I would try.

It might be possible to use a ribbon cable between the Pi and the screen (you'd need a female connector for the Pi and a male for the screen) with another connector to attach to the breadboard.
That way, you'd have the best of both worlds

Gor
Posts: 9
Joined: Tue Jan 12, 2016 4:44 pm

Re: Question about: Touch screen + breadboard and safety rul

Wed Jan 13, 2016 3:30 pm

Thank you @Burngate

So far I was able to figure out how to boot raspberry without screen.
Info for next users who get here looking answer:

1 - I prepared SD with raspbian and booted with ethernet by adding to
cmdline.txt option ip=192.168.0.2 (free ip in my local network) at the end of line.

2 - logged in via SSH with default login: [email protected] and pass: raspberry
3 - copied kernel7.img provided on DVD to /boot/
4 - copied modules provided on DVD to /lib/modules
5 - configured /etc/modules-load.d/modules.conf

snd-bcm2835
i2c-bcm2708
i2c-dev
spi_bcm2835
flexfb
fbtft_device

6 - added file /etc/modprobe.d/flexfb.conf

options flexfb width=320 height=480 regwidth=16 init=-1,0xb0,0x0,-1,0x11,-2,250,-1,0x3A,0x55,-1,0xC2,0x44,-1,0xC5,0x00,0x00,0x00,0x00,-1,0xE0,0x0F,0x1F,0x1C,0x0C,0x0F,0x08,0x48,0x98,0x37,0x0A,0x13,0x04,0x11,0x0D,0x00,-1,0xE1,0x0F,0x32,0x2E,0x0B,0x0D,0x05,0x47,0x75,0x37,0x06,0x10,0x03,0x24,0x20,0x00,-1,0xE2,0x0F,0x32,0x2E,0x0B,0x0D,0x05,0x47,0x75,0x37,0x06,0x10,0x03,0x24,0x20,0x00,-1,0x36,0x28,-1,0x11,-1,0x29,-3
options fbtft_device debug=3 rotate=90 name=flexfb speed=16000000 gpios=reset:25,dc:24

I took this options from DVD file etc/modules-4

7 - update /boot/cmdline.txt to:

dwc_otg.lpm_enable=0 console=tty1 console=ttyAMA0,115200 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait fbcon=map:11 fbcon=font:ProFont6x11 fsck.repair=yes root wait

most important part is fbcon=map:11. This LCD get attached to fb1 not fb0 . everything else is up to you
8 - halt system,
9 - attach screen
10 - boot it!

I stopped here, because I don't need X system here. But if you need X system, replace org settings from fb0 to fb1.

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rurwin
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Re: Question about: Touch screen + breadboard and safety rul

Wed Jan 13, 2016 3:41 pm

Gor wrote:Any suggestions to avoid it, except obvious one (like do not attach to breadboard while PI is on ) ?
For anyone who doubts the wisdom of this, here is what happened when I was tempted not to switch off before rewiring:
Image
The top of the chip cut my cheek as it flew past.
The legs are bent because I kept it in my wallet for several years as a reminder.

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