aBUGSworstnightmare
Posts: 1618
Joined: Tue Jun 30, 2015 1:35 pm

Re: LVDS add-on for Raspberry models with 40pin GPIO

Sun Dec 01, 2019 4:32 pm

bird2000 wrote:
Sun Dec 01, 2019 12:19 pm
Thx, than the explanations and the way offered by Peter are correct and MichaRs comments targets to a other context. But the main questions about the new PCB you haven't answered - ETA and location?
ETA= When it's done
Location: Germany

aBUGSworstnightmare
Posts: 1618
Joined: Tue Jun 30, 2015 1:35 pm

Re: LVDS add-on for Raspberry models with 40pin GPIO

Thu Dec 26, 2019 2:51 pm

As a little Christmas present I want to show you what I've been working on: the LVDS4PI EVO --> an evolution step of the LVDS4PI.

The EVO has a simpler board layout, simpler DC/DC circuitry and a more advanced LVDS transmitter, now supporting JEIDA and VESA from a single board and with dual-channel LVDS output!
IMG_1171_small.jpg
top view of the LVDS4PI EVO, connected to an RPi4 (mounted in an armor case)
IMG_1171_small.jpg (90.72 KiB) Viewed 671 times
IMG_1170_small.jpg
LVDS4PI EVO driving a SVGA TFT during testing
IMG_1170_small.jpg (89.34 KiB) Viewed 671 times

LTolledo
Posts: 2588
Joined: Sat Mar 17, 2018 7:29 am
Location: Anime Heartland

Re: LVDS add-on for Raspberry models with 40pin GPIO

Sun Dec 29, 2019 12:56 am

looks neat! up to what resolution does it support?

I've got a screen from my now defunct Vaio (15" 2K screen) and been looking for LVDS for that.....
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"

Some people be like:
"Help me! Am drowning! But dont you dare touch me nor come near me!"

aBUGSworstnightmare
Posts: 1618
Joined: Tue Jun 30, 2015 1:35 pm

Re: LVDS add-on for Raspberry models with 40pin GPIO

Sun Dec 29, 2019 7:15 am

LTolledo wrote:
Sun Dec 29, 2019 12:56 am
looks neat! up to what resolution does it support?

I've got a screen from my now defunct Vaio (15" 2K screen) and been looking for LVDS for that.....
max resolution supported by the LVDS transmitter is QXGA = 2048×1536pixels.

I've only tested up to FHD (1920x1080) so far.


aBUGSworstnightmare
Posts: 1618
Joined: Tue Jun 30, 2015 1:35 pm

Re: LVDS add-on for Raspberry models with 40pin GPIO

Sat Jan 04, 2020 8:12 am

IMG_1189.jpg
Google Nexus 7 Gen1 display
IMG_1189.jpg (68.61 KiB) Viewed 420 times
... and yes! It can drive the Nexus 7 Gen1 display too

Raquena
Posts: 13
Joined: Wed Aug 14, 2019 11:11 am

Re: LVDS add-on for Raspberry models with 40pin GPIO

Thu Feb 20, 2020 12:11 pm

Hello guys,

I've found a quite interesting IC for dual LVDS interface.
It seems to have the same functionality as the DS90, at lower cost and smaller footprint.
The problem: The footprint is so small that isn't suitable for regular cheapo PCB manufacturers...

https://datasheet.lcsc.com/szlcsc/1912 ... 410488.pdf

What do you think about it ?

Raquena
Posts: 13
Joined: Wed Aug 14, 2019 11:11 am

Re: LVDS add-on for Raspberry (SINGLE CLOCK, DUAL CLOCK?))

Thu Feb 20, 2020 12:19 pm

Hello again,

I just forgot to ask something else...

There are some screens using two clock differential pairs, some other only use one.
As far as I understood, the ones with two differential pairs are older, and the newer ones are using only one.
To keep backwards compatibility, the DS90C387 has both of them available.

If you only use one of them, the second one is left unconnected, right? (have read somewhere at the datasheet)
When using only one clock differential pair, does require a different DS90C387 pin configuration ???

is that what the DUAL pin is for ???

Sorry for the questions that may be trivial for some.

Thanks!

aBUGSworstnightmare
Posts: 1618
Joined: Tue Jun 30, 2015 1:35 pm

Re: LVDS add-on for Raspberry models with 40pin GPIO

Fri Feb 21, 2020 5:40 am

Raquena wrote:
Thu Feb 20, 2020 12:11 pm
Hello guys,

I've found a quite interesting IC for dual LVDS interface.
It seems to have the same functionality as the DS90, at lower cost and smaller footprint.
The problem: The footprint is so small that isn't suitable for regular cheapo PCB manufacturers...

https://datasheet.lcsc.com/szlcsc/1912 ... 410488.pdf

What do you think about it ?
BGA package ... Easy to solder in a reflow oven

aBUGSworstnightmare
Posts: 1618
Joined: Tue Jun 30, 2015 1:35 pm

Re: LVDS add-on for Raspberry (SINGLE CLOCK, DUAL CLOCK?))

Fri Feb 21, 2020 5:44 am

Raquena wrote:
Thu Feb 20, 2020 12:19 pm
Hello again,

I just forgot to ask something else...

There are some screens using two clock differential pairs, some other only use one.
As far as I understood, the ones with two differential pairs are older, and the newer ones are using only one.
To keep backwards compatibility, the DS90C387 has both of them available.

If you only use one of them, the second one is left unconnected, right? (have read somewhere at the datasheet)
When using only one clock differential pair, does require a different DS90C387 pin configuration ???

is that what the DUAL pin is for ???

Sorry for the questions that may be trivial for some.

Thanks!
???
Nothing is older or newer! This is dual channel LVDS were odd and even channels have their own clock.
What the pin is used for should be stated in the spec.

Sounds like you do not understand how the LVDS transmitters are working.
IMG_1232.jpg
18.5in FHD (1920x1080pixel) dual-channel LVDS interface driven by LVDS4PI EVO
IMG_1232.jpg (109.21 KiB) Viewed 74 times
IMG_1233.jpg
close-up of the connector
IMG_1233.jpg (107.06 KiB) Viewed 74 times
Example above is using an 18.5in Full-HD display module. (spec is here https://www.sharpsde.com/products/displ ... roductview) .
You usually need dual-channel if your displays resolution is bigger than WXGA (1366x768pixels).

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