[Balloon] Balloon4

Top Page
Attachments:
Message as email
+ (text/plain)
Delete this message
Reply to this message
Author: David Bisset
Date:  
To: balloon
Subject: [Balloon] Balloon4

I'd like to respond in general to the points raised to date.

Firstly it's really important that we don't forget that B4 is not Beagle.
What does this mean?
a) B4 is chasing a completely different market sector (embedded equipment, adaptable systems, portable systems).
b) B4 is not, by design, a desktop PC replacement, or a netbook. (It's not designed to do code development 24/7)
c) B4 is not trying to become the "standard" OMAP 3 development tool. (Beagle and derivatives already fulfil that slot cheaply and effectively.)
d) We can do things differently.

Secondly, the design for B4 is the core design for all derived products (e.g. Challenger).
It therefore needs to try and address current and future needs in the market we are interested in.
So B4 needs to be
a) Embeddable, or at least its derivatives need to be.
b) Power efficient.
c) Adaptable (Beagle is not).
d) Manufacturable, and low volume manufacturable.

So what about visual output?

Why do we need it?
a) for native development.
b) for the end application.

What sort of visual output do we need?
For native development we need a large graphic area, good resolution etc.
This could be VNC or USB or other remote technologies.
In most cases dev does not need fast complex graphics.
In nearly all cases remote connection is preferable as given the embedded nature of B4 it is likely that the target device is not on a bench but buried inside some 'kit'.
If an application does need good graphics then chances are a good display (or a connection to one) has been designed in to the system, so that needs to be possible but is not essential.

For the end application we will need either an LCD, nothing, a TV output or a large monitor.
LCD we can do, both large and small.
TV S-Vid we can do, but this is not going to win friends in some quarters, but as it comes for free lets have it.
Monitors; most monitors have DVI (of some flavour) some have HDMI, large TV's have HDMI and SCART/Composite.
So why should we try and support full blown HDMI? (as opposed to DVI on a non standard connector).
It is immaterial how we deliver DVI except for the PCB cm^2 required for the connector.
As Steve points out proper compliant HDMI requires consortium membership ($5k min per annum + approvals costs etc), well out of even TCL's reach given the low level of potential use.
What most people are asking for is DVI, Beagle happens to deliver this via a non-standard connector to save cm^2.

Conclusion:

Go for a connector (as low a cm^2 count as we can manage) that delivers DVI.
We need to discuss what this means both in terms of the connector reusability as GPIO and the spec for the DVI.
Any extra signals needed for HDMI should be there in case someone wants to pay the $ to get it sorted.
This will do the "connect it to a monitor" for native development , and the connect to large TV (with the same large red warning stickers as Beagle).

This leads on to what I see as the bigger debate.
What connectors do we want "On B4" and what are we prepared to put on an expansion board.
What needs to be on B4, what will represent the best use of space?
The functional requirements for B4 at this stage are mixed, and this mix may be confusing the design process.

My take on this is to keep the on-board connectors to a minimum (others may disagree):
a) To reduce board space.
b) To prove that the design is embeddable (As IO speeds go up this gets harder, and as power/standby control needs to be better this gets harder)
c) to make B4 embeddable (Challenger has to be embeddable, B4 may not be).

Counter to this is the need to have a standalone system.
However a processor board with minimal connectors that combines with a breakout board making a usable standalone system should be completely acceptable and may better allow B4 to be embeddable in its own right.

We have always said that B4 will arrive with an expansion board from day one.
I'll do my best to ensure that this happens in the same time frame as B4.
So the major question is Whats on B4 and Whats on the expansion board?
Or is everything on B4 and there is no need for an expansion/breakout board?

Thoughts please on all the different issues above.

Regards

David