First, I'm mostly an analog engineer just now getting into microcontroller design. I'll be using the XC167 and am have trouble finding external memory. I have 12MB of external memory area and am therefore looking for 12MB of memory. Ive been looking for synchronous DRAM but can only find 64MB and greater. Does anybody have recommendations for external memory?
"It's a shame that people like you have to second guess every design that does not fit the mold that you are used to. Questioning something is one thing, but constantly assuming that no one else can make a right choice unless it passes your litmus test is what I find annoying." I couldn't agree more with this. So Erik, what's the upper limit on RAM for this processor? What's the maximum latency before 'real time' becomes 'real enough time'?
So Erik, what's the upper limit on RAM for this processor? What's the maximum latency before 'real time' becomes 'real enough time'? 1) I think you get one thing wrong "real enough time" is worse than real time. It is an exprtession invented by the URTOS developers to excuse the sluggedness of their creations. The maximim latency is waht the developer know (s)he can live with, NOT what some URTOS developer has decided. 2) the upper limit for any processor is "what you need" Now to answer what you really ask I question everything that is not "typical" unless it is qualified. Not becuase it does not "fit my mold" but because - as seen in the C to asm thread where you had to question an excellent suggestion from Andy - that nobody knows what the app is when the OP does not state so. Thus if it is "unusual" and no reason is given I try to provoke an answer. Due to your cuddeling no answer has yet come forth from the OP in this thread. I find it wrong to let someone trundle along and make a board with 12M of RAM if all they need is a few hundered k. Maybe it is your philosophy that if someone want to commit suicide you should give them a gun, that is not mine. Erik
"I think you get one thing wrong "real enough time" is worse than real time." No. I asked you what you think the maximum latency is before 'real time' becomes what you call 'real enough time'. In other words, how slow does it have to be, in your opinion, before it is no longer real time. "The maximim latency is waht the developer know (s)he can live with" And there you are - it depends on the application. "the upper limit for any processor is "what you need"" I'm glad you can see that - it it 'what you need' rather that 'what Erik thinks it should be'. "Thus if it is "unusual" and no reason is given I try to provoke an answer." No you don't - you just state that the poster is wrong. Take a look at what you said in this thread: "if you need 12Mbyte, I think you are in deep doo-doo" Without knowing anything about the application you've just stated that 12Mb of RAM is wrong. "Due to your cuddeling no answer has yet come forth from the OP in this thread." I've no idea what 'cuddeling' is, and I'm unable to see how you can know that whatever it is has affected whether the OP chooses to answer your question. "I find it wrong to let someone trundle along and make a board with 12M of RAM if all they need is a few hundered k. Maybe it is your philosophy that if someone want to commit suicide you should give them a gun, that is not mine." The guy has stated that 12Mb of memory is what he's been told to provide. Why do you insist on badgering him to justify this? The reason is that you just assume, as usual, that (quoting Walt) if things don't pass your personal litmus test they must be wrong.
"Thus if it is "unusual" and no reason is given I try to provoke an answer." No you don't - you just state that the poster is wrong. If you have a better way to provoke an answer, I would like to know it. The guy has stated that 12Mb of memory is what he's been told to provide If "I have 12MB of external memory area" is being "told to provide", then the english language has changed. "Due to your cuddeling no answer has yet come forth from the OP in this thread." I've no idea what 'cuddeling' is, and I'm unable to see how you can know that whatever it is has affected whether the OP chooses to answer your question. It sure has, his "answer" is "You guys are hilarious......LOL" instead of "I need 12 M because". re "cuddeling": when I try to make the OP state a why, you always come in and post "there is no reason to tell us why, we will give help you go anywhere you want without any concern for whether it is the right path. Again, If someone ask for a gun, I check for a potential suicide, you provide the gun. You do your thing, I do mine but PLEASE stay away from comments about my persona, if you have something techincal to add, by all means do. Erik To all: I am sorry that when Stefan attacked my person, I responded the same way, I should not have done that.
"If you have a better way to provoke an answer, I would like to know it." You could try the normal method - asking a polite question? "If "I have 12MB of external memory area" is being "told to provide", then the english language has changed." If you were to read his other posts all would be revealed: "I am a Hardware Engineer being given requirements by software as far as how much memory." "It sure has, his "answer" is "You guys are hilarious......LOL" instead of "I need 12 M because"." You'll notice, however, that he made that comment before I entered into this thread. Do you not realise it's a reaction to *your* badgering? "re "cuddeling": when I try to make the OP state a why, you always come in and post "there is no reason to tell us why, we will give help you go anywhere you want without any concern for whether it is the right path." No, I'm just trying to achieve some sort of balance where posters are given some credit for having a clue, and opinions stated as though they were facts are not allowed to overwhelm the forum. You still haven't explained what 'cuddeling' means. "if you have something techincal to add, by all means do" It's pointless - you'll defend an untenable position for a while, then you simply stop responding to points that you've been picked up on. " I am sorry that when Stefan attacked my person, I responded the same way, I should not have done that." I didn't notice a personal attack?
It's pointless - you'll defend an untenable position for a while, then you simply stop responding to points that you've been picked up on. " I am sorry that when Stefan attacked my person, I responded the same way, I should not have done that." I didn't notice a personal attack? "It's pointless - you'll ....", If the above is not a "personal attack" pray tell what it is, I see nothing related to a technical problem. Anyhow I will say no more since answering any of the above would be answering "comments on the person rather than the technical issue" with "comments on the person rather than the technical issue" which has no place in a technical forum. As to the original issue, I still doubt that 12M is the right size, but that got lost in the "comments on the person rather than the technical issue" Erik
Yeah I'm starting to get a headache over this much memory.......Apparently the software engineer was told he may need upto 2MB just for fonts for multiple languages (Korean type fonts?). He wants all of it there for development though. Now I have a question based on your experience using this processor. Basically I'm not far enough along to know how fast you can actually access memory, i.e. how many instruction cycles? Is fast sram (10ns) much faster than standard sram with a 70ns response time? The XC167 is only 40Mhz. I know the memory itself is much faster, but is there really a big difference in this application? Im considering using Psuedo SRAM.......I know you have an opinion, dont be shy......LOL
""It's pointless - you'll defend an untenable position for a while, then you simply stop responding to points that you've been picked up on.", If the above is not a "personal attack" pray tell what it is, I see nothing related to a technical problem." How you can misconstrue that as a personal attack is beyond me. It was what has turned out to be a perfectly accurate prediction of your response based on your posting history. The fact that it contained no technical content does *not* make it a personal attack. What it does express, however, is the futility of attempting to engage you in a technical discussion due to your refusal to even consider the possibility that your 'one size fits all' opinions are not universal truths. "As to the original issue, I still doubt that 12M is the right size" As usual, based on exactly zero knowledge of the application. "but that got lost in the "comments on the person rather than the technical issue" I don't know anything about your 'person' other than what you write on this forum. Anything you post here is open to debate - that's what a forum is for. If you post your baseless opinions as facts you'd better expect me to disagree with them. If that hurts your feelings, well, too bad.
Yeah I'm starting to get a headache over this much memory.......Apparently the software engineer was told he may need upto 2MB just for fonts for multiple languages (Korean type fonts?). He wants all of it there for development though. RE fonts; I have yet to see an app with fonts in SRAM, I have seen a plethora of apps with fonts in Flash. I have - among several others - done a limited Japanese which took about 400k. Now I have a question based on your experience using this processor. Basically I'm not far enough along to know how fast you can actually access memory, i.e. how many instruction cycles? I'm sorry, but here you will need to refer to the data sheet, so many factors influence this. Is fast sram (10ns) much faster than standard sram with a 70ns response time? Well, I'll take a guess that it is 7 times faster :) I know the memory itself is much faster, but is there really a big difference in this application? I do not recall if the 167 is one of the chips with a software programmable memory timing, if it is this will be a need vs cost decision Get at this "programmer"s butt and get it clear what (s)he need in flash (program, fonts and other permanent storage) and how much in SRAM. I would not be surprised if you end up with just one SRAM chip Erik PS in Flash you can get much more memory per chip than with SRAM (unless someone know about some chips I have not heard about)
Mike, I'm sorry your thread has been hijacked. I'd love to help but I'm not familiar with the XC167. Given that you are just starting out with microcontroller design I'd suggest that you spend a couple (more) days studying the datasheet and application notes for the device, all should become clear. I did have a quick look at the documentation for this part available on Keil's website and it looks pretty comprehensive.
As usual, based on exactly zero knowledge of the application. 1) absolutely correct at that time I had "exactly zero knowledge of the application", However a board with 24 memory chips is "rather unique" isn't it?. 2) your criticism of my statement "it is not so" is based on you having "exactly zero knowledge of the application" so where is the difference in the qualification of the post. 3) now see in other postings what is coming out of the fact that my "baseless opinions as facts" brought out a more complete description of the app so that "exactly zero knowledge of the application" is no longer true. This enabled me to give the OP some "real" help. If you post your baseless opinions as facts you'd better expect me to disagree with them. If that hurts your feelings, well, too bad. I have no problem with you disagreening with what I say, but I have a problem with you commenting on how I say it. I just ask that you disagree with the content, not the verbage. I realize that you think that if someone want to put 12Mbyte SRAM (24 memory chips) on a board that is "normal". That is fine, but is it not very interesting that while you have been busy arguing my verbage, I, not you, ended up posting solutions for the OP. No feelings are hurt, just PLEASE: disagree all you want with the content of my posts, my verbage is mine and if it offends you tough!. Erik
"Basically I'm not far enough along to know how fast you can actually access memory, i.e. how many instruction cycles? Is fast sram (10ns) much faster than standard sram with a 70ns response time? The XC167 is only 40Mhz. I know the memory itself is much faster, but is there really a big difference in this application?" This really depends on many things, but I would guess that 70ns is fast enough. The fastest loop to copy data from one place to another I can think of looks something like this:
; R1 = source address ; R2 = destination address ; R3 = address of R0 ; R4 = source data end address LOOP: MOV R0,[R1+] ;read source word MOV [R2+],[R3] ;write to destination CMP R1,R4 ;end of data? JMPR cc_ULT,LOOP ;jump if not
"However a board with 24 memory chips is "rather unique" isn't it?." In your sphere of experience, maybe. In other applications maybe not. "your criticism of my statement "it is not so" is based on you having "exactly zero knowledge of the application" so where is the difference in the qualification of the post." It's simple. Based on zero knowledge you say "It is wrong", I say "It may be right, it may be wrong". "now see in other postings what is coming out of the fact that my "baseless opinions as facts" brought out a more complete description of the app so that "exactly zero knowledge of the application" is no longer true. This enabled me to give the OP some "real" help." It took so long, I suspect, because you never actually asked the OP for a description of his application. Go on, take a look back through the thread. All you did was churn out your usual ignorant barrage of "you're wrong! you're wrong!". "I have no problem with you disagreening with what I say, but I have a problem with you commenting on how I say it. I just ask that you disagree with the content, not the verbage." Disagreeing with the content is exactly what I have been doing. However, I do have a problem with the way you say things as well. There is a certain expectation in a professional forum that you try to behave in a civilised fashion. Take a look at this quote from another current thread: "If someone were to pay me to look at the above code, I would say "no thanks". So, I have absolutely no intention of even glancing at unformatted code for free." What a nasty and aggressive way of pointing out that the poster's code wasn't formatted to your liking! " I realize that you think that if someone want to put 12Mbyte SRAM (24 memory chips) on a board that is "normal"." Yet again you seem to be incapable of grasping my simple point. I am not suggesting that any particular quantity of memory chips is 'normal', I am saying that different applications require different quantities of memory chips. There is no 'normal', and there is certainly no arbitrary limit set by you. "That is fine, but is it not very interesting that while you have been busy arguing my verbage, I, not you, ended up posting solutions for the OP." Solutions? "No feelings are hurt, just PLEASE: disagree all you want with the content of my posts," Thanks for your permission. " my verbage is mine and if it offends you tough!." Two other regular posters have commented on your 'verbage' and general attitude in recent threads. If this doesn't make you think about your behaviour then your level of ignorance and arrogance is quite extraordinary.
Did you get all your fuzzy feelings out, I hope so. There is absolutely no technical merit to your post above. I do not deal in feelings, if that is what you want to discuss, I suggest you find a forum on that subject. THE END unless you, as before, state that my attempt of terminating this useless discussion is "then you simply stop responding to points that you've been picked up on"
Mike, send me a ping at erikm@digrec.com, I have to critisize another techical post and do not want to continue discussing with Stefan how I do it. Erik
"Did you get all your fuzzy feelings out, I hope so." What are 'fuzzy feelings'? Are they the same as the yet unexplained 'cuddeling'? "There is absolutely no technical merit to your post above." There is technical merit in my post - I point out yet again that your sweeping statements about what is acceptable in a design are incorrect. This is of benefit to anyone who may be misled by those statements. "I do not deal in feelings" Being an engineer does not exempt you from being part of the human race. It does not give you the right to behave in a way that others find offensive. "if that is what you want to discuss, I suggest you find a forum on that subject" I have no interest in discussing feelings. I have merely pointed out that I am not alone in finding your attitude at best rude and at worst ignorant. "THE END unless you, as before, state that my attempt of terminating this useless discussion is "then you simply stop responding to points that you've been picked up on"" Well, that's exactly what you've done. As predicted.