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Author Topic: FT82x  (Read 4277 times)

armadafg

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Re: FT82x
« Reply #15 on: August 31, 2018, 08:57:15 AM »

Hi,

So why for example the gameduino2 that uses the ft800 with 256k and the gameduino3 that uses the ft810 with 1M its both block has 2048 commands ?
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Rudolph

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Re: FT82x
« Reply #16 on: September 02, 2018, 04:01:53 PM »

All FT8xx so far have 8k of memory for the display-list, that is 2048 32-bit words.
Expanding this to 64k would be nice on first glance but then everything still would need to be executed for every single frame.
So at the same time the chip would need to be much faster.

This reminds me of a different "issue".
The divider for the clock only works well for small displays.
800x480 is configured to 928 h-cycles und 525 v-cycles, that are 487200 clock-cycles.
A typical value for the divider would be REG_PCLK = 2 which means that a FT81x uses 30 MHz.
In return these settings result in about 61 frames per second, nice.

Now I have this 1024x600 TFT from Glyn.
For some reason (I suspect a flaw in the design on Glyns side) these can not be used with the full clock of 60MHz.
As these are configured to 1100x720 this would result in 75 frames per second anyways.
The recommended value is 20MHz and therefore 25 fps and they work well with 30MHz which results in 37 FPS.

The issue I have there is that the divider does not allow for fractional values, so I could not configure it to
use 45MHz for example which would result in 56 fps.

Now the upcoming BT81x uses 72MHz.
That is nice, so the 1024x600 panel could be used with 45 fps.
The 800x480 panel at REG_PCLK = 2 would run with 73 fps so we need to make that REG_PCLK = 3.
But then it would be clocked with 24MHz and "only" 49 fps.

If for whatever reason you would need to fine-tune the frame-rate you simply could not do that.
One could come up with the idea to manipulate the base-clock but the datasheet does not give a frequency range, the only allowable frequency is 12MHz.
The PLL could be changed to multiply by 2...5 (6 with BT81x).

At higher resolutions this would even become more of an issue.

Do I want higher resolutions or do I need them?
No, not really, I would be fine with 4 pixels per mm for HMI. Or make that 8 pixels per mm.
The typical 800x480 7" has 11 pixels per mm.
But what I need are bigger displays and there close to none 800x480 or 800x600 panels bigger than 7" out there.
And the bigger panels do not only have higher resolutions, they also typically do not have a RGB interface anymore but LVDS instead.






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armadafg

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Re: FT82x
« Reply #17 on: September 05, 2018, 03:31:32 PM »

Thank you for your reply Rudolph :) ,

So you want to say that if we increase the memory for the display-list to 16K for example there would be 30 img / s instead of 60 and it does not vary according to the instruction in question or it depent of what its instructions ? (here for 480 * 800)

For my part I will not have the benefit of having more pixel, 5" and 480 * 800 are fine.

Creating another chips that will be managed more resolutions why not but it is not my priority.
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Rudolph

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Re: FT82x
« Reply #18 on: September 07, 2018, 12:13:16 PM »

>So you want to say that if we increase the memory for the display-list to 16K for example there would be 30 img / s instead of 60

No, I am saying that if the display-list would be increased the chip also would need to be made faster.
At least fast enough to handle 60 FPS for the max designated resolution which now is 800x600.

Only the first three lines of my post refer to the limited display-list, the rest has nothing to do with it. :-)

And maybe it even currently is fast enough to handle 16k for example, from a few observations I can only tell that it is pretty fast already,
but not how busy it really is from frame to frame.

I was merely pointing out that expanding the display-list memory looks like an easy thing to do from the outside, for example the gfx-memory could be reduced at the same time so the overall memory stays the same.
But it is more complicated then that and there is not much information around about how the FT8xx do function internally.

Thinking about it I wonder for example how the lists really work.
The display is written out line by line with no frame-buffer.
The objects however are all over the display-list. You can display a picture at the start of the list on top of the screen, lots of things in the next instructions and then a text to be printed across that picture at the end of the list.
So one way to do it would be to process the whole display-list for every single pixel - which I find a bit unlikely.
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armadafg

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Re: FT82x
« Reply #19 on: September 10, 2018, 03:57:44 PM »

I really hope the next br82x will have more than 16k of memory.
512k. The absolut dream  ;) 8)  :o  ;D
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armadafg

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Re: FT82x
« Reply #20 on: September 23, 2018, 12:33:38 AM »

Hi,
While waiting for the next chip to handle more than 2048 instructions, but do you know if hotmcu is expected to use the BR 815/6?
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armadafg

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Re: FT82x
« Reply #21 on: September 28, 2018, 08:41:36 AM »

I would also like to know when the bt82x will be available.
On your site it is indicated June 2018 but I do not see it anywhere
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FTDI Community

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Re: FT82x
« Reply #22 on: September 28, 2018, 11:16:55 AM »

Hello,

The BT81X should be available by the end of the year.

Best Regards,
FTDI Community
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Rudolph

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Re: FT82x
« Reply #23 on: October 02, 2018, 09:34:31 AM »

I do not know about Hotmcu and I am not sure if I really want to anymore.

But it looks like Matrix Orbital has plans for BT815/BT816 modules: https://www.matrixorbital.com/ftdi-eve/eve-bt815


>The BT81X should be available by the end of the year.

Hmm, not so nice.

Okay, what about updating the datasheet and perhaps the programming manual in advance, perhaps with a fat PRELIMINARY watermark across all pages?
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armadafg

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Re: FT82x
« Reply #24 on: October 25, 2018, 01:09:28 PM »

Yes maybe but the problem is that Hotmcu's screens are much cheaper
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Rudolph

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Re: FT82x
« Reply #25 on: October 25, 2018, 05:07:03 PM »

That is the problem for me Hotmcu's screens are much cheaper and not so much less expensive.

And the BT815/BT816 are in full release now. :-)
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armadafg

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Re: FT82x
« Reply #26 on: October 26, 2018, 11:07:29 AM »

when i say "much cheaper " i mean "less expensive". (translation problem fr -> en, sorry)
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Rudolph

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Re: FT82x
« Reply #27 on: October 27, 2018, 01:48:09 PM »

I was aware of what you mean but I wanted to point out that I have an issue with the quality they deliver.
Sure, these are good value for the money, not bad products, but I want more value.


Now that the datasheet for the BT81x is released, these support up to 2GBit of QSPI NOR flash. :-)
And they can play animations and videos directly from external flash plus using fonts and images.

Some interesting features include UTF font support, printf style text output, using strings from memory.

I only have to get a BT815 module now.... :-)
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armadafg

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Re: FT82x
« Reply #28 on: October 29, 2018, 02:45:18 PM »

2...G...B    :-O
Unbelievable

I hope Hotmcu you have one with the 2Gb because for my project I find that their quality is sufficient
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Rudolph

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Re: FT82x
« Reply #29 on: October 30, 2018, 06:16:35 AM »

I just learned that 2Gbit is rather unlikely since, at least by now, you will not find these in SOIC-8 or WDSON-8 packages but BGA packages.
Well, 64MBit already would be a huge step up, SOIC-8 would mean 256MBit max and WDSON-8 would mean 512MBit max.
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