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Rockbox mail archiveSubject: Re: remote controlRe: remote control
From: Andreas Zwirtes <zwirtes_at_gmx.de>
Date: Thu, 10 Oct 2002 22:26:23 +0200 Well, we didn't discuss the circuit. I think almost anybody would have come up with a similar solution for the hardware, because the path is already laid. Most people wouldn't have thought about pulling currents in off mode or static charges... But what about the software, what do you think of this protocol? Issue power port: Ok, I don't like drawing power from a processor pin as you might guess, but that seems to be a big discussion point. What do you think of a short standard frame that we call "give me power for 100ms"? So the Archos knows, when to provide power, he nows how long and it cannot be turned on accidentally. The possibility to implement such a frame is given any time, so we don't have to worry about. We can implement it whenever we want with this protocol. Also the solution is very easy and every controller will be able to decide, if he want's to have power or not. Even if we decide, that this feature is too dangerous (maybe some guys fried their controllers), it is possible to turn it of with the next rockbox version. The controller just has to answer "not implemented" (NACK). Especially for controllers with limited current driving capabillities like the Hitachi, port pin powering is a safety issue. Well, maybe the first step is to figure out, how much the voltage will break down if we load the controller with 1mA. If it goes below 2,8-3V, it'll be useless. Matt: Thank you. Every suggestion is appreciated and I saw some good points. Well, if you understand the protocol (wich is not complete by now and not even aggreed), you'll see that there already is a framework to build ahead. All the layers below application don't have a clue what is going on. You can even send pictures, if you like. Also every remote can have it's own functionality. And even if the player doesn't support it, there'll be no problem, because it tells the remote that he cannot provide the data. Sketches for a remote like in your description would be very interesting. Programmable buttons would be easy to implement with a proxy layer, but I think, there's already a big discussion on that. Maybe the remote should have it's own configuration facility and use a proxy layer that implements easy functional routing. Stuart: If you plug in the off the shelf remote, at first there'll be nothing going on. I don't think that the remote will send a wakeup frame to the archos. Since I do not have a remote here, could somebody check that? We also have to check, if the original remote is protected against collision. Maybe it is not, because the Archos is always switched to receive mode. We should be on the safe side, if we always let the slave start the communication. So it really has to be master and detect connection or power up/down. Stuart again: It is always possible connect different hardware solutions. You also can use a 3.3V RS232 pegel converter, if you make sure that it is possible to switch it to highZ (open). That would always be necessary, there's no way round. Every remote will have to switch it's TX off, when it's not transmitting anything. The description was just a suggestion how to connect a controller. I have easy circuits for PCs here, that should work. You don't even need a controller, when talking to a PC. It is quite a bit complicated to put an external UART on every remote. You don't know the interface and it will draw more power in battery powered remotes. But if we use the AVR controller line, we are able to use the same software in 8pin / 4k up to 144pin/256k (maybe even more) processors. There also is a GCC port for this device, I beleive. I think we will have to use different hardware for a handy LCD, a PC remote and some others. I agree, that is would be usefull to implement one standard interface with external UART and some buttons / lcd. But that won't be the ideal mobile solution. And it is not necessary for PC or palm, because they could use a very simple cable interface that only uses passive parts. The IRC should be the right place to discuss smaller issues. This here is quite right in the mailing list, since it is sorted a little bit on topic. What do you think about starting a design document? It could describe hardware and software interfaces. Is everybody able to view/edit RTF file format? Andrew: Agree. I also think it is a good idea to make different devices, simple cables and weird remotes. Bye, Andreas [radhard] Received on 2002-10-10 Page template was last modified "Tue Sep 7 00:00:02 2021" The Rockbox Crew -- Privacy Policy |