[Arm-netbook] 480 × 272 5" LCD lash up ready for testing

[joem]

On Thu, 2013-09-19 at 10:39 +0100, luke.leighton wrote:
> On Thu, Sep 19, 2013 at 9:28 AM, joem <joem at martindale-electric.co.uk> wrote:
> > On Thu, 2013-09-12 at 10:09 +0000, joem wrote:
> >> Hi,
> >>
> >> A 480 × 272 5" LCD which costs <$15 has been lashed up for testing:
> >>
> >> http://www.gplsquared.com/eoma_boot/eoma_boot.html#lcd_lashup
> >>
> >> The LCD is a KD43G18-40NB-A1.
> >> Aliexpress store sell these LCDs
> >> http://www.aliexpress.com/wholesale?SearchText=KD43G18-40NB-A1
> >>
> >> Datasheet http://www.gplsquared.com/eoma_boot/KD43G18-40NB-A1-1.pdf
> >>
> >> Anyone got a time to do a time saving uSD image
> >> configured for 480 x 272 operation that I can try for
> >> a bit of quick verification :) ?
> >
> >
> > The LCD was wired up with 3.3V and 18V + 100R in series
> > for the back light last night.
> 
>  whoopeee!
> 
> > Notice one problem straight away.
> > That particular model of LCD requires a DEN signal
> > The DEN or Display ENable signal informs the LCD
> > to ignore the data on the IO lines while the CPU
> > is booting, or when the video bus is doing
> > something unrelated to video. There is no DEN signal from
> > the MEB,
> 
>  yes there is. on
> http://rhombus-tech.net/community_ideas/micro_engineering_board/
>  you can see it's pin 29.

That be the EN signal which tells the LCD to tell when to load
in the data for each horizontal line, and ignore data when the
LCD controller reconfigures itself for the next line of horizontal
line data.

The DEN signal prevents the display from working
until after CPU has booted and set its IO lines. Otherwise the LCD
will show junk data while the IO lines are being set up.


>  this comes from here:
> http://elinux.org/Embedded_Open_Modular_Architecture/EOMA-68#Table_of_EOMA-68_pinouts
>  which is pin 48.
> 
> > If the EOMA has spare pins, I recommend adding a DEN line
> 
>  already taken care of.
> 
> 
> > At the moment the LCD is not being initialised properly.
> > The boot log is here
> > http://www.gplsquared.com/eoma_boot/lcd_boot_log.txt
> 
> <4>[DISP] *** Err01: Violate "lcd_hbp > lcd_hspw"
> [    5.635979] [DISP] *** Err01: Violate "lcd_hbp > lcd_hspw"
> <4>[DISP] *** Err02: Violate "lcd_vbp > lcd_vspw"
> [    5.645902] [DISP] *** Err02: Violate "lcd_vbp > lcd_vspw"
> <4>[DISP] *** Err03: Violate "lcd_ht >= (lcd_hbp+lcd_x*1+4)"
> [    5.656779] [DISP] *** Err03: Violate "lcd_ht >= (lcd_hbp+lcd_x*1+4)"
> <4>[DISP] *** Err04: Violate "(lcd_vt/2) >= (lcd_vbp+lcd_y+2)"
> [    5.673792] [DISP] *** Err04: Violate "(lcd_vt/2) >= (lcd_vbp+lcd_y+2)"
> 
>  ok so you need to change those values so that the double-checks pass.
>  just experiment until you have it ok?  although... to be honest, that
> LCD's so common i'm sure you'd be able to find someone who's done this
> already.
> 
> > The script.fex used is here
> > http://www.gplsquared.com/eoma_boot/script.fex


As can be seen, the fex file is set up correctly, but boot log says
the  software thinks lcd_x, lcd_y etc are all set at 0!


        <4>[DISP] *** Interface:[    5.546614] [DISP] ***
        Interface:<4>[DISP] *** Parall
        [    5.552634] [DISP] *** Parallel HV Panel
        <4>[DISP] *** Lcd Frm Disable
        [    5.559431] [DISP] *** Lcd Frm Disable
        <4>[DISP] ***
        [    5.564496] [DISP] ***
        <4>[DISP] *** Timing:
        [    5.568858] [DISP] *** Timing:
        <4>[DISP] *** lcd_x:      0
        [    5.574443] [DISP] *** lcd_x:      0
        <4>[DISP] *** lcd_y:      0
        [    5.580548] [DISP] *** lcd_y:      0
        <4>[DISP] *** lcd_ht:     0
        [    5.586644] [DISP] *** lcd_ht:     0
        <4>[DISP] *** lcd_hbp:    0
        [    5.592749] [DISP] *** lcd_hbp:    0
        <4>[DISP] *** lcd_vt:     0
        [    5.598845] [DISP] *** lcd_vt:     0
        <4>[DISP] *** lcd_vbp:    0
        [    5.604950] [DISP] *** lcd_vbp:    0
        <4>[DISP] *** lcd_hspw:   0
        [    5.611054] [DISP] *** lcd_hspw:   0
        <4>[DISP] *** lcd_vspw:   0
        [    5.617151] [DISP] *** lcd_vspw:   0
        <4>[DISP] *** lcd_frame_frq:  0Hz
        [    5.623777] [DISP] *** lcd_frame_frq:  0Hz