Beagle Board with LVDS 7.6 in OLED

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1

Hello,

I'm currently working on a project to drive a 7.6 in LVDS OLED display
via the LCD headers on the Rev. C board.
Has anyone been able to interface the Beagle Board with a LVDS
display? I'm using a SN75LVDS83B TTL to LVDS converter for the
hardware, but what changes need to be made to the software? The 7.6
OLED has a 800X480 resolution.

Thanks

2

You will also need to level shift the signals from the connector to 3.3V. The signals supplied by the connectors from the Beagle are at 1.8V.

Gerald

3

Thanks for the fast reply,

According to the Datasheet (http://focus.ti.com/lit/ds/symlink/
sn75lvds83b.pdf) of the SN75LVDS83B this chip will accept the 1.8 V
signals directly from the OMAP3530. I understand that the previous
version (SN75LVDS83) needed the 3.3V signals, but TI made some
modifications to interface directly with the 1.8V signals from the
OMAP . Is the level shifting still necessary?

Thanks,

4

If you look at the schematic of the Beagle, you will see that there is already a load on the bus from the TFP410 as well as 33 ohim series resistors. It is your call, but if it were me, I would add the buffrers to celan up the signal.

Gerald

5

What is the 33 ohm resistors for? Is this to attenuate reflections and/or
serve as a basic termination or was there a different intent?

6

It is to attenuate reflections due to differences in impedance between the source and load. It is SOP for LCD interfaces on OMAP.

Gerald

7

SOP = Standard Operating Procedure?
Other abbreviations: SOP - Wikipedia

Best regards and thanks
  Søren

It is to attenuate reflections due to differences in impedance
between the source and load. It is SOP for LCD interfaces on OMAP.

Gerald

>
> What is the 33 ohm resistors for? Is this to attenuate reflections

and/or

8

Yep. Every single OMAP EVM made in the history of OMAP, nicluding all 20 that I have designed, has had these resistors. This makes it Standard Operating Procedure.

Gerald

9

I know that the resistors are standard on all EVMs, but I just hate abbreviations, since they might mean different things to different people. In order to be completely sure you wasn’t referring something strange I simply just didn’t know anything about, I thought better to ask to be 100% sure/clear.

Thanks for clarifying

Søren

10

What next? You want to know what OMAP stands for? I suppose you hate that too.

Gerald

11

What next? You want to know what OMAP stands for? I suppose you hate that too.

It's an abbrevation? I heard conflicting stories about it :slight_smile:

regards,

Koen

12

It actually means absolutely nothing. You cannot trademark an abbreviation or acronym.

Gerald

13

It actually means absolutely nothing. You cannot trademark an abbreviation

or acronym.

Gerald

What next? You want to know what OMAP stands for? I suppose you hate that

too.

Why should I?

WRT OMAP at least many years ago Nokia had the following understanding:
http://press.nokia.com/PR/199905/776838_5.html

OMAP = Open Multimedia Application Platform?

Isn't that correct?
  Søren

14

No it is not!

Gerald

15

Are u kidding or serious ?

Taken from http://www.ti.com/sc/docs/products/dsp/newcores/faq.htm

Q. What is OMAP?
A. Open Mulitimedia Application Platform (OMAP) combines the C55x DSP
and software interfaces or APIs that will enable 3rd parties to write
multimedia applications accelerated by the DSP for wireless
Smartphones, PDAs and other digital internet appliances.

Q. How will these cores compare with competitor offerings for 3G
wireless applications?

    * We believe TI's C55x and C64x offers wireless OEMs the best
solution for their 3G requirements.
    * For advanced, 3G wireless handsets and mobile computing devices,
the TMS320C55x delivers ultra-low power consumption of 0.05 milliWatts
per Million Instructions per Second (MIPS), six times lower than the
industry leading C54x and any competitor in this space. As a result,
the 'C55x will extend battery life in 3G handsets, allowing wireless
end users to take advantage of advanced functionality and data
services, without surrendering wireless convenience and portability.
    * For next-generation phones, TI is already publicly engaged with
two of the world's leading phone manufacturers: Nokia and Ericsson.
These two companies, combined, represent nearly half of today's
digital cell-phone production.
    * Both announced their plans to use TI's C55x enabled ***Open
Multimedia Application Platform (OMAP)*** for their implementations
across all next-generation standards, starting with 2.5G and
continuing into 3G.
    * TI's next generation TMS320C64x DSP core is ideal for the needs
of wireless infrastructure manufacturers, delivering the highest
performance DSPs in the world, with scalable speeds of up to 1.1
GigaHertz (GHz) and performance near 9,000 MIPS.
    * In 3G basestations, TI has significantly increased its market
position from 2G, having engagements now with 8 of the world's top 10
base station manufacturers. The C64x platform will help to extend TI's
leadership in wireless infrastructures.
    * Both cores also have the benefit of code and pin-for-pin
compatibility with the C54x and C64x DSPs.

rgrds, viral