XPS-3216, transmitter specifications - Page 15 - RC Groups
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May 08, 2012, 08:45 PM
Fly inverted, it's more fun.
tholmes345's Avatar
Originally Posted by kgfly
As you suggested Jim, leave sorting to a helper application on the PC. So long as the model memories can be managed from a PC and then loaded back onto the Tx, this really is a non-issue IMO. The reality is that very few users will have more than 20 models and scrolling through a list of even 100 is not particularly difficult.

What comes to my mind is that you are talking about filename restrictions. I hope they do not translate to model name restrictions. That is, the model name should be an attribute stored in the file. If there are technical limitations that mean the filename cannot be the same as the model name then that should not be an issue. Indeed, model filenames could simply be "Model.001", "Model.002" or any other arbitrary way of generating unique filenames. Then the presentation on-screen can be decoupled from the filenames. This allows for usefully long model names (e.g. 32 characters) which tend to be needed for anyone with more than a handful of models.

Such an approach, combined with the concept of an index file may also simplify the sorting/ordering issue. The index file maps between <modelname> and <filename>. If it is a simple text file (.csv perhaps) then it can be sorted on a PC or the user could even edit it manually to create any preferred grouping or ordering.

What he said.

Do you not try to attract the maximum number of XPS users (purchasers). And potential users of XPS? I would expect that the average modleler would have 20 or less models, although I know some that have more. It is easy to accommodate 20 or more. The rest, although desireable as potential champions for XPS, would no doubt be a very small minority. They would have to deal with what they consider to be short comings of the system. I cannot imagine that sorting through a pile of SD cards would be better than scrolling throught the list in the Tx. My take on this that you, Jim, should do what you consider is good for the health of the XPS company. So far you have done a great job of giving most of us what we want. Thank you.
Last edited by tholmes345; May 08, 2012 at 08:55 PM.
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May 08, 2012, 10:30 PM
Model names are hard coded to 16 characters. Each model occupies 8K of space. This includes 32 channels of data, each with 8 flight modes and triple rates, plus the model name, a 32x32 pixel thumbnail image, flight mode names (10 chars each), output channel names (10 chars each), and other things. 8192 bytes is quite a bit of storage space and I am using just about every byte of it. In order to be able to switch flight modes on the fly and mix between modes, you have to have all of the data in RAM. I tried every trick I could thick of to load the new flight mode, but nothing I came up with provided glitch-free control.
May 08, 2012, 11:21 PM
Registered User
OK so model names are 16 chars and filenames are 8.3 so hence the two are decoupled.

Presumably the user never needs to know or care about the filenames so long as there is a PC app that can be used to manage the contents of a flash card and extract model files so they can be emailed to other XPS users.

Similarly, any future sorting capability would be based on model name not filename.
May 09, 2012, 12:01 AM
I have considered using the long file name compression to 8.3 format.
May 09, 2012, 11:05 AM
Registered User
Originally Posted by JimDrew
You can't realistically bubble sort the FAT table. This is what drive optimizers are for. It takes 131ms to write a single block to a SD media card (average speed is much faster if you are writing multiple blocks contiguously but we don't have that option). So, every time you needed to move the two entries on the bubble sort, the sorted block has to be re-written. Even caching the last used block (which I do for reads), writes still are writes. Even with a delayed write, you are talking many, many, seconds to perform a sort when the number of files exceeded just a few dozen. I can't imagine that this would be acceptable.
Its been a long time since I did any programming but the solution to this problem as I remember it was to define pointers to the name then just sort the pointer file. That way you don't have to move any data around.
May 09, 2012, 03:53 PM
There is not enough memory to hold that many model names to define pointers. I have a total of 16K of RAM, 8K of which contains the current model. 2K is for the graphics display. 2K is for the local variables and stack space. 2K is for font data. 2K is for the DMA buffer space (256 for RF, 256 for serial, and 1K for A to D sampling). I can use the graphics space for temporary storage, but everything else has to be left alone. When I was using FLASHROM for model storage, I just maintained a section of the FLASHROM for the model name and the pointer to where in the FLASHROM the data resided. I could sort this very fast (7us write time), so speed was never an issue. It makes me want to go back to this method and just use the SD-media card for off-sight storage and only have 500 models of local storage. The SD-media card is still great for things like sound/speech samples and music.
May 09, 2012, 05:01 PM
Registered User
It's your project. You choose.

May 09, 2012, 05:08 PM
Registered User
But if you only had 500 model capable TX I would still buy it. Even if I could only store 100 models that would be fine, even 50 I could live with. But that is about it. I don't like the 25 or 30 or 35 limit, as I have more aircraft than that.
May 09, 2012, 05:15 PM
Fly inverted, it's more fun.
tholmes345's Avatar
Two transmitters. Twice the models with a back-up.
May 09, 2012, 06:00 PM
I realize that 100 models is probably more than most RC enthusiasts will have in a lifetime, so using the SD-media just for loading/backing up models is an option. As it is now, its really slow to access models. That takes away from the rest of the transmitter's incredibly fast (100% assembly code) perceived value.
May 09, 2012, 06:27 PM
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Grich's Avatar
1 million models is wasted space. 500 models is still too much but leaves room for dreaming. 100 models is fine, i have 55 models, gliders, powered gliders, foaminess, biplanes, 3d ships, very fast wings, and helicopters. And i'm still looking at some new ships.
May 09, 2012, 06:31 PM
Registered User
Grich's Avatar
oh yea forgot to mention the flying waffle. see it on YouTube under "waffle airplane"
it's the one that shows blue sky and has a caption of waffles with butter and syrup.
May 09, 2012, 07:31 PM
Chillaxin dude!
BulletMaster's Avatar
slow access to the SD card is an issue with the 11X radio too.. If you backup models and then re-instate, it seems to take ages. And they are only 30 model memory onboard (+ infinite SD storage). But you can't access the model from the SD card, you need to bring it to an on-board storage location.
May 09, 2012, 07:32 PM
Registered User
Other than bragging rights, 1M models is pointless and since it seems that it detracts from the usability of the Tx, seems undesirable. I would certainly think that 100 models is plenty, especially if the user has the option of swapping the current batch of 100 with another batch on the SD card, although that too seems only marginal worthwhile. Given the price of this Tx, if someone has more than 100 models they can simply buy another and still be ahead of the game compared to most functional competitors.
May 09, 2012, 08:12 PM
Build more, websurf less
FlyingW's Avatar
In my opinion 100 models is way more than enough. I could live with 24, as I have two transmitters now with 8 and 16 memories and I'm ok with that. I have some memories used by models I no longer have, but were complicated to set up (for example helis and 6-servo sailplanes) so I want to save them.

I could live with less than 24 if it were possible to save and retrieve model setups offline to and from the SD card or to a PC to free up transmitter spots.

Thanks for the opportunity provide input. Paul

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