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???
09/06/06 14:52
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 		 #123757 - let's sort it out
Responding to: ???'s previous message
Still talking about the "dedicated programmer" not "cable". I knew M.Asim Khan's "schematics" is far from being perfect; but then any schematics alone is useless, isn't it.

So let's just take the schematics as a basis and let's talk about it (I wanted to prepare an alternative schematics but it requires some time):
Kai Klaas said:
1. Line D3 is used to turn the micro on and off. If D3 goes low after being high, 74HCT367 outputs are immediately activated. But due to the fact, that the BC557 needs some microseconds to turn-on, the 74HCT367 drives the inputs of micro, allthough the micro isn't turned-on yet. That's not a good idea.

Let's set forth; almost any tristateable 74HCTxxx would be good enough, isn't it? 74HCT125, for example, or 74HCT373/573? Or goo' ol' HCT245?

As far as the order of signals, I'd turn the transistor on then based on the output of 74HCTxxx - set one input to VCC and connect the base resistor to that output, perhaps with one resistor grounding it when tristated?

Kai said:
2. If line D3 goes high again, outputs of 74HCT367 are immediately turned-off, while the micro still gets power. Due to the internal pull-down resistor at reset pin of micro, the potential at reset pin becomes low. And this during power down, where the reset pin should be high to prevent damage from the flash memory content! The urgently needed pull-up at reset pin is omitted.

A pullup on reset to the transistor output, is it enough?

Kai said:
3. Not even one series termination resistor can be seen for the signals entering the cables!

Granted. They are there, surprisingly, on v3.0...
What about adding some small capacitors, 100pF?

Kai said:
4. No decoupling cap for the micro!

Sure.

Kai said:
5. In the line D4 a strange 1k5 resistor is inserted, looking like a "solved" timing problem...

The same problem as in item 3.

Kai said:
Do you really think that this is a circuit suited for newbies??
I'd believe the newbies are less likely to cheat on resistors than on 74-anything; especially if they are explained the reasons.

Please, comment.

JW



List of 232 messages in thread
TopicAuthorDate
SPI ISP issues            01/01/70 00:00      
   SPI ISP issues - part 2            01/01/70 00:00      
      SPI ISP issues - part 3            01/01/70 00:00      
   plural            01/01/70 00:00      
      Fora is certainly correct            01/01/70 00:00      
         no, it's not ...            01/01/70 00:00      
            great post!            01/01/70 00:00      
   I think the biggest problem is with the AT            01/01/70 00:00      
      maybe            01/01/70 00:00      
         It's not necessarily the product ... it's the docs            01/01/70 00:00      
            OK let them be so            01/01/70 00:00      
               It's true, they shouldn't be used by anyone.            01/01/70 00:00      
                  What would you suggest to use?            01/01/70 00:00      
                     Anything else at all would be fine ... even a PIC            01/01/70 00:00      
                        Whaaaat???            01/01/70 00:00      
                           ANYTHING but Atmel products!            01/01/70 00:00      
                              Come on, Richard...            01/01/70 00:00      
                                 well, I, for one, agree with Richard            01/01/70 00:00      
                                    Bullshit! Stating such is entirely ridiculous!            01/01/70 00:00      
                                       how can a FACT be \\\'ridiculous\\\"?            01/01/70 00:00      
                                          It's ridiculous, because you deduce...            01/01/70 00:00      
                                             single event?            01/01/70 00:00      
                                                Yes, and hundreds of events with Philips,            01/01/70 00:00      
                                                   a VERY high up 'idiot'            01/01/70 00:00      
                                                Well, mine was a long series of events            01/01/70 00:00      
                                                   there may be hope, sorry Kai            01/01/70 00:00      
                                                      It will be a WARM December day in Moscow            01/01/70 00:00      
                                                         maybe someone found out            01/01/70 00:00      
                                                            The penalty isn't severe enough            01/01/70 00:00      
                                                               blame the rest of the bunch            01/01/70 00:00      
                                                                  Well, as I said, it's like U.S.-made cars            01/01/70 00:00      
                                 If they'll do it to US, they'll do it to YOU!            01/01/70 00:00      
                                    Do you really think that others are better??            01/01/70 00:00      
                                       all comapanies have things to blame them for            01/01/70 00:00      
                                          Indeed!            01/01/70 00:00      
                                             a maxim about maxim            01/01/70 00:00      
                                             Once upon a time ... there were second sources ...            01/01/70 00:00      
                                       I don't love Philips, either            01/01/70 00:00      
                                          I don't 'love' any company, but I 'love' to work w            01/01/70 00:00      
                                             Once upon a time there were FAE's who knew things.            01/01/70 00:00      
                                                once upon a time ...            01/01/70 00:00      
                                                   Yes, it\'s like the grocery store            01/01/70 00:00      
      The biggest problem is            01/01/70 00:00      
         do it - under my name            01/01/70 00:00      
            All right, here is it...            01/01/70 00:00      
               Kai .. we're not getting a bit sensitive here ?            01/01/70 00:00      
                  noooooo................ hmm, maybe a bit...            01/01/70 00:00      
                     Why does this come up so frequently?            01/01/70 00:00      
                        Because there is so much trash in the www!            01/01/70 00:00      
                           Maybe we can provide a local "fix" for that            01/01/70 00:00      
                              Great idea, but...            01/01/70 00:00      
                                 the other side of the coin            01/01/70 00:00      
                                    A fool who trusts on phantasy programmers            01/01/70 00:00      
                                       Kai the issue is            01/01/70 00:00      
                                          Exactly!            01/01/70 00:00      
                                          Little Joe            01/01/70 00:00      
                                             did you not know            01/01/70 00:00      
                                             especially since he\'s been deceased for some time            01/01/70 00:00      
                                       Lots of those "fantasy" programmers are for sale            01/01/70 00:00      
                                          What a trash!            01/01/70 00:00      
                                             Oddly enough, similar circuits work for JTAG            01/01/70 00:00      
                                                Driving cables is nasty!!            01/01/70 00:00      
                                                   framkly, I wish eval-board makers would heed this            01/01/70 00:00      
                                                      Have you tested series termination?            01/01/70 00:00      
                                                         would be great, but            01/01/70 00:00      
                                                         Kai, I think that would be a WONDERFUL addition!            01/01/70 00:00      
                                    Well, what I am thinking ...            01/01/70 00:00      
                                       Yeah, but what's that to do with ISP?            01/01/70 00:00      
                                       grits, yes, oatmeal, no            01/01/70 00:00      
                                          Some of 'em will look, read, and do SOME work            01/01/70 00:00      
                                             and the winner is            01/01/70 00:00      
               An alternative to Atmels ISP CABLE            01/01/70 00:00      
                  Profiting from highest noise margins            01/01/70 00:00      
                  comparator            01/01/70 00:00      
                     Not so well suited...            01/01/70 00:00      
                        I don't understand.            01/01/70 00:00      
                           Check the spec-sheets            01/01/70 00:00      
                           I am sorry...            01/01/70 00:00      
                              cables et al            01/01/70 00:00      
                                 Cables...            01/01/70 00:00      
                                    software            01/01/70 00:00      
                                       ps            01/01/70 00:00      
                                       To be honest...            01/01/70 00:00      
                                          Atmel software... a piece of @%^&            01/01/70 00:00      
                                             it's for amateurs            01/01/70 00:00      
                                                ??            01/01/70 00:00      
                                             Not at all            01/01/70 00:00      
                                                dear amateurs, be realistic            01/01/70 00:00      
                                                   Erik, did you mean...            01/01/70 00:00      
                                                      Why, oh, why            01/01/70 00:00      
                                                         why, oh why            01/01/70 00:00      
                                                            not the issue            01/01/70 00:00      
                                                but you ARE professional!!!!            01/01/70 00:00      
                                                   now, I'm going to upset Richard            01/01/70 00:00      
                                                      ICE?            01/01/70 00:00      
                                                      No success stories            01/01/70 00:00      
                                                         Exactly!            01/01/70 00:00      
                                                      Grrrr! Well, maybe not this time ...            01/01/70 00:00      
                                             it makes you wonder, doesn't it?            01/01/70 00:00      
                  ATMEL cable with the HC            01/01/70 00:00      
                     another idea            01/01/70 00:00      
                        please, pretty please            01/01/70 00:00      
                           there is no magic            01/01/70 00:00      
                              you said it            01/01/70 00:00      
                                 you got me wrong            01/01/70 00:00      
                                    do not blame me for what YOU said :)            01/01/70 00:00      
                                       teaching is hard            01/01/70 00:00      
                                          good analogy, the question is            01/01/70 00:00      
                                             when I turned my back...            01/01/70 00:00      
                                                you forgot            01/01/70 00:00      
                                                   filter            01/01/70 00:00      
                                                      nope            01/01/70 00:00      
                        upside-down            01/01/70 00:00      
                           and the 3rd reader            01/01/70 00:00      
                              he already did            01/01/70 00:00      
                                 a good one            01/01/70 00:00      
                                    tell it beforehand            01/01/70 00:00      
                              The newbie SHALL try to build his stuff, but...            01/01/70 00:00      
                                 allow a reply of \"you stupid idiot\" to anyone            01/01/70 00:00      
                        Will not do the trick, unfortunately            01/01/70 00:00      
                           decoupling the LPT lines?            01/01/70 00:00      
                              Low state noise margin...            01/01/70 00:00      
                                 and with a Schottky?            01/01/70 00:00      
                                    No, I wouldn't recommend this            01/01/70 00:00      
                                       www.reichelt.de            01/01/70 00:00      
                                          Ok, to be more precisely...            01/01/70 00:00      
                                             can you please draw it down?            01/01/70 00:00      
                                                Replace the 74VHC244 in the original circuit            01/01/70 00:00      
                                    How would a germanium work?            01/01/70 00:00      
                                       Could work!            01/01/70 00:00      
               thanks, Kai!            01/01/70 00:00      
                  Schottky diodes            01/01/70 00:00      
                     to Schottky or not to Schottky :-)            01/01/70 00:00      
                        Yes, but we must assume a minimum standard...            01/01/70 00:00      
                           shopping            01/01/70 00:00      
                              My point is..            01/01/70 00:00      
                        You can use an array            01/01/70 00:00      
                           Your search - 74S1023 - did not match any document            01/01/70 00:00      
                              SN74S1053            01/01/70 00:00      
                              OOPS! it is 74S1053 ... sorry!            01/01/70 00:00      
   the issues            01/01/70 00:00      
   a most telling thread            01/01/70 00:00      
      The root problem is that the first thing one needs            01/01/70 00:00      
   "dedicated programmer"            01/01/70 00:00      
      what's difficult to understand ...            01/01/70 00:00      
         Ok, how do you propose they program and erase the            01/01/70 00:00      
            I would not be quite so sure about that            01/01/70 00:00      
            Keep in mind that this is for newbies ...            01/01/70 00:00      
               but they still have to build it            01/01/70 00:00      
      Only because it looks simple does not mean...            01/01/70 00:00      
         he's desperate            01/01/70 00:00      
         there are lots of circuits published like this!            01/01/70 00:00      
            I used to have memory mapped I/O in virtual            01/01/70 00:00      
               I wouldn't say that ...            01/01/70 00:00      
                  that threy learn to drive with a stick shift            01/01/70 00:00      
                     Once again, you are exaggerating ...            01/01/70 00:00      
                        the point I\'m trying to make (and believe that I            01/01/70 00:00      
                           Yes, but in 101 you've got to use a '51 or '31            01/01/70 00:00      
                              nonono            01/01/70 00:00      
                                 Perhaps you\'re right, in this case ...            01/01/70 00:00      
                                    I don't think so            01/01/70 00:00      
                                       Ah but..            01/01/70 00:00      
                              halelujah!            01/01/70 00:00      
                           the problem with RD2 is...            01/01/70 00:00      
                              what cost the most            01/01/70 00:00      
                                 cost            01/01/70 00:00      
                                    patience is what it takes            01/01/70 00:00      
         let's sort it out            01/01/70 00:00      
   Richard, you aregue things that, while valuable ,            01/01/70 00:00      
   Its not the cables if you ask me.            01/01/70 00:00      
      an interesting thought            01/01/70 00:00      
         It's probably not JUST this part ...            01/01/70 00:00      
      not the cable alone            01/01/70 00:00      
         it will, but            01/01/70 00:00      
      It simply has to do with the numbers            01/01/70 00:00      
         maybe not quite ...            01/01/70 00:00      
            I was assuming...            01/01/70 00:00      
               a case like that ...            01/01/70 00:00      
                  I have            01/01/70 00:00      
                     Perhaps it's that the approach is wrong            01/01/70 00:00      
                        I guess I have seen those ... ...            01/01/70 00:00      
   fresh thoughts            01/01/70 00:00      
      ???????????????            01/01/70 00:00      
         I'm puzzled, too, Jan            01/01/70 00:00      
            2 different things            01/01/70 00:00      
               au contraire            01/01/70 00:00      
                  from the ISP point of view...            01/01/70 00:00      
                     if you have "no reset and oscillator"            01/01/70 00:00      
                        sure            01/01/70 00:00      
                           Ok \"in-situ programming\" works but that is not ISP            01/01/70 00:00      
                              Does this scheme actually work reliably?            01/01/70 00:00      
                                 Guiness book?            01/01/70 00:00      
                                    This all goes back to the "AT" in the part number            01/01/70 00:00      
               Nothing magic with reset and oscillator            01/01/70 00:00      
                  I am talking about the rusty nail            01/01/70 00:00      
                     Yes, here you are right!            01/01/70 00:00      
                        just helping            01/01/70 00:00      
                           200            01/01/70 00:00      
                           not quite, but I like the idea            01/01/70 00:00      
                           Exactly!            01/01/70 00:00      
                              ... and that's why I advocate for the 8032 version            01/01/70 00:00      
                                 Stuff it            01/01/70 00:00      
                                    This will soon be moot            01/01/70 00:00      
                                       Central Europe?            01/01/70 00:00      
                                    Mistake...            01/01/70 00:00      
                                       you think so, I do not            01/01/70 00:00      
                                          Better hope...            01/01/70 00:00      
                                             no love there            01/01/70 00:00      
                                    Nothing is perfect...            01/01/70 00:00      
                                       HUH            01/01/70 00:00      
                                          waitaminute            01/01/70 00:00      
                                             same desert            01/01/70 00:00      
                                                it appears so            01/01/70 00:00      
                                 male cow manure            01/01/70 00:00      
                                    Eprom programmers are cheap and simple            01/01/70 00:00      
                                       Cheaper than a $25 Atmel cable ?            01/01/70 00:00      
                                          Yes, and widely applicable, too            01/01/70 00:00      
                                             beware            01/01/70 00:00      
                                                That's the usual line from an Asian vendor in U.S.            01/01/70 00:00      
   fresh experience            01/01/70 00:00      
      I am not going to vote 'off topic' but            01/01/70 00:00      
         I am still just thinking aloud...            01/01/70 00:00      
   just helping            01/01/70 00:00      
   222 posts WOW!!            01/01/70 00:00      
      EEEK! Why would you get that close?            01/01/70 00:00      
         post number 224 and counting            01/01/70 00:00      
            Well, I\'m a dog person ...            01/01/70 00:00      
               226            01/01/70 00:00      
                  tie a brick around his neck            01/01/70 00:00      
                  %$#@! it happened again!            01/01/70 00:00      
                     Programming Dogs            01/01/70 00:00      
                        230 tried it            01/01/70 00:00      

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