Hi all, In RTX we can assign a function as a task with the _task_ #NO tag. When calling os_create_task we just pass this task number as a parameter. Assume one has to use banking, in this case, how does RTX identify, in which bank the function exists ? from where does rtx get information about the banks of any task at runtime ? regards pachu
If you don't need a more powerful processor there's no benefit in using one. A more powerful processor is also likely to consume more power which for many applications is a problem. Timing - Timing - Timing what about it? When you overload the poor little bugger, suddenly your serial int does not get processed in ti,e and a fuse blows because you do not get a port pin pulled low fast enough. Of course if you suffer from tyhe misconception that the '51 is a microprocessor rather than a microcontroller, all your wrong statements will be right if that premise is accepted. Erik BTW re the statement about power consumption; for some reason '51s whatever the derivative are anything but power misers.
"Timing - Timing - Timing what about it? When you overload the poor little bugger, suddenly your serial int does not get processed in ti,e" How do you figure that? Interrupts interrupt the normal flow of program execution. It doesn't matter what the foreground process is doing. But once again you seem to think that using certain tools or facilities will inevitably 'overload' the 8051. I keep trying to explain to you that this is not a Universal Truth. You may believe it, but you are wrong. "and a fuse blows because you do not get a port pin pulled low fast enough." You design circuits with the 8051 that blow fuses when port pins are high? Time for another look at the drawing board, I think. "Of course if you suffer from tyhe misconception that the '51 is a microprocessor rather than a microcontroller, all your wrong statements will be right if that premise is accepted." I don't really get this. You're saying I'm right if I call the thing by a different name? "BTW re the statement about power consumption; for some reason '51s whatever the derivative are anything but power misers." However, I take it that you can see some sort of link between more powerful processors and increased power consumption?
"Of course if you suffer from the misconception that the '51 is a microprocessor rather than a microcontroller, all your wrong statements will be right if that premise is accepted." I don't really get this. You're saying I'm right if I call the thing by a different name? A microprocessor is a numbercruncher that should react in less than a second, a microcontroller is a device that shall react NOW. If you want to mislabel the '51 as a microprocessor (which it aint) you can state all kinds of things from that premise.
"you seem to think that using certain tools or facilities will inevitably 'overload' the 8051." But there is no point in using code banking unless you've exceeded the 8051's address space - so that is inherently an "overload" of sorts! The real benefit of an RTOS really comes with larger systems, when the limitations of a simple "main loop" start to get in the way; so, as I said earlier, "if you've decided that a 'small' controller like an 8051 is suitable for your project, I can't really see why you should then need to use an RTOS."
amen
so, as I said earlier, "if you've decided that a 'small' controller like an 8051 is suitable for your project, I can't really see why you should then need to use an RTOS." Here are a few reasons... 1. The RTOS solves a problem that you can't or don't want to code (possibly incorrectly) my way around. 2. You will save development time that you can put to better use elsewhere. 3. The MCU has enough horsepower to run the RTOS and your application. 4. The complexity of the 8051 (with an RTOS) is simpler than some other architecture. 5. You have experience with the 8051 and RTOS. All of these sound like pretty good reasons to me. Jon
"All of these sound like pretty good reasons to me." Well, potentially good reasons...! ;-) <cynic>But you would say that - you've got an RTOS to sell...!</cynic> ;-) I didn't say it's impossible - just seems pretty improbable to me.
"A microprocessor is a numbercruncher that should react in less than a second, a microcontroller is a device that shall react NOW." 97.3% of statistics are made up on the spot. 98.2% of definitions of the words 'microcontroller' and 'microprocessor' also appear to be made up on the spot. One thing that neither a microprocessor or microcontroller can do is respond "NOW". I assume you're familiar with interrupt latency? "If you want to mislabel the '51 as a microprocessor (which it aint) you can state all kinds of things from that premise." I'm not really interested in labelling it as either as the distinction between the two has become hopelessly blurred.
"But there is no point in using code banking unless you've exceeded the 8051's address space - so that is inherently an "overload" of sorts!" Do you consider using more that 64k of NV xdata storage an 'overload'? "if you've decided that a 'small' controller like an 8051 is suitable for your project, I can't really see why you should then need to use an RTOS." You may not *need* to use an RTOS. Using one, however, may be a convenient and effective way of coding a given application.
Yes, RTX51 and RTX51 Tiny save the current code bank in the Task Control Block (TCB). Reinhard
as said before "the '51 PC" may have been realistic when more powerful processors were an order of magnitude more expensive. I think the point is that more powerful processors may still be an order of magnitude more expensive if you're not talking about some ultra-high-volume consumer electronics product. If the OP is making something for industry where he's going to sell only tens of units per year, and he is only really confident with the 8051, then he will simply not be able to amortize away the extra development time and learning curve climbing that he'll have to do to learn a new processor. Further, if the 8051 will do everything acceptably, then there's no reason for him to even attempt so. I try to squeeze in some learning about new processors whenever I can, but sometimes you've got a timeline that suggests you work with what you know.
OOPS "But there is no point in using code banking unless you've exceeded the 8051's address space - so that is inherently an "overload" of sorts!" Do you consider using more that 64k of NV xdata storage an 'overload'? Nobody said anything about data exceeding 64k. I have such, but access it by other means than Keils "banking" with associated overhead Erik
I think the point is that more powerful processors may still be an order of magnitude more expensive if you're not talking about some ultra-high-volume consumer electronics producth Digi-key sell Philips ARM processors at qty 1 priced $6 and up Erik
"Nobody said anything about data exceeding 64k." Er, yes *I* did. I was drawing a parallel between using more code space than the 8051 was designed to address and more xdata space that the 8051 was designed to address. "I have such, but access it by other means than Keils "banking" with associated overhead" You cannot access more than 64k of xdata without *some* overhead. The 8051 is not designed to address more than 64k. According to your philosophy you have used the wrong microprocessor for the job.
Digi-key sell Philips ARM processors at qty 1 priced $6 and up You've missed my point. Even if the more powerful processors sell for HALF the price of the 8051, you can't amortize out the extra development time for learning the architecture unless you sell ALOT of products. For instance, take the following math: Digi-Key 87C51FB33 @ qty. 1 = $7.76 Digi-Key ARM @ qty. 1 = $6.00 (I don't know ARM stuff, so I'll use your number) Now assume (since the OP wants to use an RTOS) that this is at least a moderately complex project. Assume that it will take 1000Hrs of programming time for the 8051 architecture with which the OP is familiar. Also assume that the RTOS price for both ARM and 8051 is the same (which might not be true). Also, we'll assume that the OP is a dynamite embedded systems guy and will suffer only a 10% degradation in efficiency switching to a new processor which means that it will take him 1100 Hrs. to complete the project with ARM. Let's just pick some reasonable billing rate for an embedded system engineer (I guess $50/Hr is likely low, but I'll be generous for my purposes here). Then, if we assume that the entire system is the same except for the processor selected and compare only incremental costs, we have this: 8051 Cost = (1000 * $50) + ($7.76 / unit) ARM Cost = (1100 * $50) + ($6 / unit) So, a break even analysis is as follows: (1000*50)+(7.76*units) = (1100*50)+(6*units) which yields units=2840 SO if all of these assumptions are correct (and I think they're reasonable), and even if we assume that the ARM cost is $1.76 less than the cost of the 8051, the 8051 makes the most money for the developers company unless he plans to sell more than 2,840 units over the product life-cycle.