Quite a lot has happened during the last week!
Nikolaus (gta04 at the boards) was mostly busy dealing with MIPI.
1. LCDs can drive you crazy!
MIPI is the standard interface LCDs are using these days - and while "standard" seems to imply it's something easy to use, it sure isn't.
"Standard" is only the communication protocol - getting the LCD to do something is something else.
You need to calculate and set size, timings, etc. everything yourself...
After a lot of reading into MIPI and how it generally works and many many patches later, he still didn't get the LCD to show a picture - but at least he can communicate with it now.
What's missing now is the startup sequence to tell the LCD to actually do something.
That's something the manufacturer should be able to tell us.
More information on that soon.
2. A good idea: What we showed at FOSDEM
You probably have all seen the small video at the FOSDEM where I showed off what you could've seen and tested there.
If not, here it is:
https://www.youtube.com/embed/ruFyq7fbfpU?feature=oembed
Designing a PCB takes a lot of time.
Not just for the design, but for debugging as well - and what's worse: You spend a lot of time simply WAITING for the prototype PCBs.
A PCB like we need it usually needs 8 layers.
The normal production time for an 8 layer bare PCB is 6 weeks - and it's pretty expensive as well (especially for just doing prototypes).
Aditionally, populating them with all of the complex parts as well (like the OMAP) costs a lot of money. Both for parts AND the population.
That's why we're doing a different approach here.
The Pyra PCB right now is a simple two layer-PCB. Can be created in a couple of days for little money.
All of our custom parts (keyboard controller, LED controller, nubs, switches, UMTS module, etc.) are populated on the PCB.
However, the complex part (the SoC) is still on the devboard.
The devboard and the Pyra PCB are connected via a special connector Nikolaus created, which includes an i²c bus, gpios, etc.
So basically, our custom parts are connected the exact same way as they will be connected on the final PCB to the SoC.
That's pretty helpful, as we can now use low-cost Pyra PCBs we can get within a couple of days to test all the hardware we want to include.
And once everything works as it should, "only" the SoC with components like RAM, power circuits, storage, etc. needs to be transplanted to the Pyra PCB - which will then be the first REAL prototype.
"Only" sounds like it's a quick thing to do - but in reality, this is A LOT of work that will need more time than the rest of the design!
That way still saves a lot of time and money though.
In case you're wondering why this hasn't been done with the Pandora back then:
Well, Michael designed the first prototype when no devboard was available (the BeagleBoard came out after that...) - an impressive amount of work!
I'm happy it's more easy this time though!
3. Headaches
One thing that's good and bad about the above mentioned way of designing the PCB:
The SoC comes last - so we are not yet fixed on the OMAP5 (we were, but the last week has shown different options as well...)
Thanks to the blogpost of PandoraLive, we got in contact with Qualcomm.
It could very well be that we can get a Snapdragon!
However, there's also the new Intel BayTrail SoC that some people here are in favour.
And Allwinner has announced the A80 which could be interesting...
There's been A LOT of discussions after my last Blog Post regarding which SoC to choose...
This is giving me a lot of headaches right now, as there are new options - and finding out which one is better than the other is not an easy thing.
While it will be me having to do the final decision, here is some poll which might be helpful to me!
Nikolaus (gta04 at the boards) was mostly busy dealing with MIPI.
1. LCDs can drive you crazy!
MIPI is the standard interface LCDs are using these days - and while "standard" seems to imply it's something easy to use, it sure isn't.
"Standard" is only the communication protocol - getting the LCD to do something is something else.
You need to calculate and set size, timings, etc. everything yourself...
After a lot of reading into MIPI and how it generally works and many many patches later, he still didn't get the LCD to show a picture - but at least he can communicate with it now.
What's missing now is the startup sequence to tell the LCD to actually do something.
That's something the manufacturer should be able to tell us.
More information on that soon.
2. A good idea: What we showed at FOSDEM
You probably have all seen the small video at the FOSDEM where I showed off what you could've seen and tested there.
If not, here it is:
https://www.youtube.com/embed/ruFyq7fbfpU?feature=oembed
Designing a PCB takes a lot of time.
Not just for the design, but for debugging as well - and what's worse: You spend a lot of time simply WAITING for the prototype PCBs.
A PCB like we need it usually needs 8 layers.
The normal production time for an 8 layer bare PCB is 6 weeks - and it's pretty expensive as well (especially for just doing prototypes).
Aditionally, populating them with all of the complex parts as well (like the OMAP) costs a lot of money. Both for parts AND the population.
That's why we're doing a different approach here.
The Pyra PCB right now is a simple two layer-PCB. Can be created in a couple of days for little money.
All of our custom parts (keyboard controller, LED controller, nubs, switches, UMTS module, etc.) are populated on the PCB.
However, the complex part (the SoC) is still on the devboard.
The devboard and the Pyra PCB are connected via a special connector Nikolaus created, which includes an i²c bus, gpios, etc.
So basically, our custom parts are connected the exact same way as they will be connected on the final PCB to the SoC.
That's pretty helpful, as we can now use low-cost Pyra PCBs we can get within a couple of days to test all the hardware we want to include.
And once everything works as it should, "only" the SoC with components like RAM, power circuits, storage, etc. needs to be transplanted to the Pyra PCB - which will then be the first REAL prototype.
"Only" sounds like it's a quick thing to do - but in reality, this is A LOT of work that will need more time than the rest of the design!
That way still saves a lot of time and money though.
In case you're wondering why this hasn't been done with the Pandora back then:
Well, Michael designed the first prototype when no devboard was available (the BeagleBoard came out after that...) - an impressive amount of work!
I'm happy it's more easy this time though!
3. Headaches
One thing that's good and bad about the above mentioned way of designing the PCB:
The SoC comes last - so we are not yet fixed on the OMAP5 (we were, but the last week has shown different options as well...)
Thanks to the blogpost of PandoraLive, we got in contact with Qualcomm.
It could very well be that we can get a Snapdragon!
However, there's also the new Intel BayTrail SoC that some people here are in favour.
And Allwinner has announced the A80 which could be interesting...
There's been A LOT of discussions after my last Blog Post regarding which SoC to choose...
This is giving me a lot of headaches right now, as there are new options - and finding out which one is better than the other is not an easy thing.
While it will be me having to do the final decision, here is some poll which might be helpful to me!
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