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connecting an lcd shield to gpio pins?
Posted: Sat Mar 29, 2014 7:08 am
by Tunppi
hello, sorry if this is the wrong forum area, but id like to get some enlightement on wheter it is possible or not to connect this shield
http://www.elecfreaks.com/store/lcd-tft ... p-213.html
with an fitting lcd to the gpio pins on raspberry, i have valdodov's software on my raspberry, and it sets the resolutions correct when booting, but i suppose my main problem is that i can't connect the pins correctly?
when i have attempted to connect this setup to raspberry ive got just blank screen?
im probably doing many things wrong, but please, if you can point me to the right direction id greatly appreciate it!
Re: connecting an lcd shield to gpio pins?
Posted: Sat Mar 29, 2014 8:38 am
by Tunppi
ive tried to look for an guide but i can't find one, if anyone could help id really appreciate it
Re: connecting an lcd shield to gpio pins?
Posted: Sat Mar 29, 2014 1:09 pm
by klricks
All the hardware and code on that page appears to be for an Arduino system.
You can't connect a random interface to the RPi GPIO header and expect it to function. In fact it is likely to damage the RPi.
I would suggest to find something else made for a RPi.
Re: connecting an lcd shield to gpio pins?
Posted: Sat Mar 29, 2014 1:58 pm
by notro
The FBTFT project has support for the ITDB24 display which has a S6D1121 controller, the same controller as the display mentioned in that page:
http://www.elecfreaks.com/store/24-tft- ... p-110.html
https://github.com/notro/fbtft/wiki
There's no need for a Arduino levelshifter shield on the Pi with that display. Both the display and the Pi has 3.3V I/O.
valdodov's driver is for a SSD1289 controller. The LCD controller is the main factor when determining if a display is supported or not.
Also consider the HY28B touch display. It uses the SPI bus, and thus uses less GPIOs.
https://github.com/notro/fbtft/wiki/LCD ... wiki-hy28b
Be aware that there are 2mm spaced pin headers on this display.
Re: connecting an lcd shield to gpio pins?
Posted: Sat Mar 29, 2014 7:07 pm
by Tunppi
thanks from the information! ill try these out
Re: connecting an lcd shield to gpio pins?
Posted: Mon Mar 31, 2014 7:30 am
by Tunppi
now i have the notros fbtft's installed on my raspbpi but i dont know do i have the correct pins connected to my gpio's, sorry, i dont have the shield anymore on the tft. my screen is this
http://www.sunrom.com/704
it has the same controller as sainsmart 3.2
i connected the pins as the sainsmart 3.2 guide has
i have vcc and led_a connected to 5v and 3.3v and ground to ground.
rest = gpio 25
t_irq = gpio 23
t_do = miso
t_din = mosi
t_cs = ce1n
t_clk = sclk
rs = gpio 24
thank you from your help
Re: connecting an lcd shield to gpio pins?
Posted: Wed Apr 02, 2014 12:40 pm
by Tunppi
hello again, now dmesg gives me this kind of error
Code: Select all
[ 421.565298] fbtft_device: SPI devices registered:
[ 421.565339] fbtft_device: spidev spi0.0 500kHz 8 bits mode=0x00
[ 421.565356] fbtft_device: spidev spi0.1 500kHz 8 bits mode=0x00
[ 421.565365] fbtft_device: 'fb' Platform devices registered:
[ 421.565386] fbtft_device: bcm2708_fb id=-1 pdata? no
[ 421.565584] fbtft_device: GPIOS used by 'sainsmart32':
[ 421.565601] fbtft_device: (none)
[ 421.565610] fbtft_device: 'fb' Platform devices registered:
[ 421.565628] fbtft_device: bcm2708_fb id=-1 pdata? no
[ 421.565659] fbtft_device: fb_ssd1289 id=0 pdata? yes
[ 421.617576] fb_ssd1289 fb_ssd1289.0: Missing info about 'dc' gpio. Aborting.
[ 421.617676] fb_ssd1289: probe of fb_ssd1289.0 failed with error -22
what should i do? thank you.
Re: connecting an lcd shield to gpio pins?
Posted: Wed Apr 02, 2014 4:18 pm
by notro
The Schematics.pdf file in LCD_SDK.zip shows that the display uses a 16-bit databus.
There's not enough gpios to use the touchpanel as well. To do that, you need something like this:
https://github.com/notro/fbtft/wiki/SPI ... ce-circuit
https://github.com/notro/fbtft/wiki/LCD ... insmart-32
Re: connecting an lcd shield to gpio pins?
Posted: Wed Apr 02, 2014 4:35 pm
by Tunppi
ok, i have bought the spi's already that i wondered would i need to do that if the gpio connection doesn't work.
thank you, you have been most helpfull.
Re: connecting an lcd shield to gpio pins?
Posted: Sat Apr 12, 2014 1:27 pm
by Treblig
Tunppi wrote:hello again, now dmesg gives me this kind of error
Code: Select all
[ 421.617576] fb_ssd1289 fb_ssd1289.0: Missing info about 'dc' gpio. Aborting.
"Missing info about '
dc' gpio" is the important thing, at least it was with my TFT01-2.2SP.
You should tell fbtft to which GPIO pin is '
dc' connected.
I spent a lot of time with this, overlooking that dmesg line...
BTW, thanks to noto for fbtft !
Re: connecting an lcd shield to gpio pins?
Posted: Thu Apr 17, 2014 2:31 pm
by Tunppi
thanks from the info treblig, now i have the microchips but id need some information regarding the connections?
https://github.com/notro/fbtft/wiki/SPI ... ce-circuit
where can i find the pin configurations used in this example?
i have 74HC04's 74hc4040's and 74hc4094's and i think ill place them like this
what pin numbers are the D, CP, MR, 0E, and STR?
thank you from your replies and guidance.
Re: connecting an lcd shield to gpio pins?
Posted: Thu Apr 17, 2014 3:07 pm
by FLYFISH TECHNOLOGIES
Hi,
Tunppi wrote:
i have 74HC04's 74hc4040's and 74hc4094's and i think ill place them like this
what pin numbers are the D, CP, MR, 0E, and STR?
It turned out several times that the most reliable answer you can get if you take a look by yourself into PDF files (datasheets) of these chips.
Google is a great tool... and also quick.
Best wishes, Ivan Zilic.
Re: connecting an lcd shield to gpio pins?
Posted: Thu Apr 17, 2014 3:36 pm
by Tunppi
okay then, thanks.