flat assembler
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MHajduk 19 Apr 2008, 18:40
Quite possible that I'm wrong but here I present my proposition.
Is it possible that heat randomly changes value of some RAM memory cells (heat has to change conductivity of semiconductors from which transistors are made)? If yes then is possible to detect temperature using software: Code: 1. Fill entire chip RAM with 0 value. 2. Check if ANY chip RAM cell is nonzero. 2a. If yes then control program should execute some operations. 3. Goto 1. |
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19 Apr 2008, 18:40 |
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revolution 19 Apr 2008, 23:49
edfed wrote: check the phase shift induced by the change of temperature? |
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19 Apr 2008, 23:49 |
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revolution 19 Apr 2008, 23:51
Alphonso wrote: Well it's got me stumped, since it's a BIG MCU I would guess it might have to be in some sort of sleep mode to detect such a small change, but it's only a guess and probably wrong. |
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19 Apr 2008, 23:51 |
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revolution 19 Apr 2008, 23:59
MHajduk wrote: Quite possible that I'm wrong but here I present my proposition. |
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19 Apr 2008, 23:59 |
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edfed 20 Apr 2008, 00:35
sleep mode == very low current consuming.
then, very high impedance of all the circuitry then, i don't know, i need to see it working to find the solution. the current induced by the touch will change something... and s***, i've found! it's because somebody touch the board, there is the solution. |
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20 Apr 2008, 00:35 |
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asmhack 20 Apr 2008, 01:31
the possible answer that comes to my mind is that then you touch it, you increase the temperature so:
a) that works as a delay in the pings maybe or b) you send some data through the port and check it if it was changed when it returns |
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20 Apr 2008, 01:31 |
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revolution 20 Apr 2008, 02:52
asmhack wrote: the possible answer that comes to my mind is that then you touch it, you increase the temperature so: asmhack wrote:
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20 Apr 2008, 02:52 |
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revolution 20 Apr 2008, 06:42
revolution wrote:
Although I did see that the temperature does affect the SDRAM discharge rate, it is very inconvenient to use as a temperature sensor. |
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20 Apr 2008, 06:42 |
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edfed 20 Apr 2008, 07:11
is the solution found?
or shall we seek many more? amazing, but i prefer a bit the SRAM... Toshiba as made a very interessting chip. 32Mb in 1 Static RAM chip @ 100 MHz 4 or 5 years ago. don't remember the reference. |
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20 Apr 2008, 07:11 |
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revolution 20 Apr 2008, 07:14
No, the solution is not SDRAM, it is something else much more reliable.
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20 Apr 2008, 07:14 |
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Alphonso 20 Apr 2008, 12:43
Well this is my last guess, better make that 'wild guess' as I know nothing of ARM processors. As it is, I'm only just starting to learn about x86 processors.
Okay, are you changing/toggling states such that your measuring the stabilization time of the 13MHz processor oscillator which possibly differs with temperature. Clutching at straws here. |
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20 Apr 2008, 12:43 |
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revolution 20 Apr 2008, 12:52
Alphonso wrote: Well this is my last guess, better make that 'wild guess' as I know nothing of ARM processors. As it is, I'm only just starting to learn about x86 processors. Alphonso wrote: Okay, are you changing/toggling states ... Alphonso wrote: ... such that your measuring the stabilization time of the 13MHz processor oscillator which possibly differs with temperature. Clutching at straws here. |
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20 Apr 2008, 12:52 |
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Alphonso 20 Apr 2008, 13:27
revolution wrote: I am relying on the crystals not changing their frequency Okay, I'll leave it to the others to find out. Look forward to seeing how you did it. |
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20 Apr 2008, 13:27 |
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edfed 20 Apr 2008, 13:32
shift 90° ?
the watchdog and the timer phase shift? if normal, the signals are aligned, and if the board is touched, it will shift one of the signals. a sort of PLL taht will permit to assert the timer or not. it is very hard to find the solution as i don't have the board in my hands.. i like to see the hardware working. even if i don't have instruments to make any mesures. a picture will be welcome. touched, and not touched ( no no i'm not miss Irma). but i need to see with my eyes. |
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20 Apr 2008, 13:32 |
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revolution 20 Apr 2008, 13:37
Alphonso wrote: It was more to do with the 64000 cycles of latency the 13MHz oscillator takes to stabilize, or maybe that is preset? Just some info I found on your web page |
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20 Apr 2008, 13:37 |
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revolution 20 Apr 2008, 13:51
It looks similar to this. Although this is not the actual board but it is close enough as to not matter.
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20 Apr 2008, 13:51 |
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edfed 20 Apr 2008, 15:09
revolution :
how many time did you need to understand this the first time? i guess if i'll understand one day ! scenario n° 435 the little LTxx is an analog circuit that will have a variation inducing a frequency or timing change somewhere. the µC will detect this change by comparing with the default value. |
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20 Apr 2008, 15:09 |
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revolution 20 Apr 2008, 15:27
It is purely a MCU process, you don't need to understand the other devices on the board. The LT thing is for the core voltage PSU.
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20 Apr 2008, 15:27 |
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edfed 21 Apr 2008, 17:48
the MCU is in sleep mode, and when touching the board, it will put the board to a particular voltage, and then, wakeup the MCU?
i really don't see how it is possible indeed. please revolution, give us the solution, we cannot wait no more... you win, you're the best. niarf! Last edited by edfed on 21 Apr 2008, 19:32; edited 1 time in total |
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21 Apr 2008, 17:48 |
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