DNA20 not sensing resistance properly

[beamrider]

I've had this box built for 3-4 months now, never a problem with it.  I've always used 3ohm Boge cartos on it, set at 8.7 watts.  In the last 2 weeks, I've had to change the carto out about every other day, and I'm thinking to myself "dammit, I musta got a bad batch" .....  Come to find out, the DNA is reading anything and everything I put on it, at 2.1ohms.

Before I open 'er up and start fiddling around, is there a way to "cold boot" this module?  I remember even if power is removed for a while, it reboots, but still remembers the previous settings.

[bapgood]

I've had this box built for 3-4 months now, never a problem with it.  I've always used 3ohm Boge cartos on it, set at 8.7 watts.  In the last 2 weeks, I've had to change the carto out about every other day, and I'm thinking to myself "dammit, I musta got a bad batch" .....  Come to find out, the DNA is reading anything and everything I put on it, at 2.1ohms.

Before I open 'er up and start fiddling around, is there a way to "cold boot" this module?  I remember even if power is removed for a while, it reboots, but still remembers the previous settings.

I have had the stuck ohm issue or maybe it was didn't read....I don't remember.....it is a soldered battery so its not as easy removing the battery. However once its drained to the point the DNA won't turn on, its works like normal after recharging.

The more I think about it, I believe mine was no ohm reading. Sorry it hasn't happened for a while. But removing power is a good place to start.

[Breaktru]

Yeah I had the zero ohms a few times myself. Removing batt power always worked.
There is also the reset by touching Pin 2 to ground. I don't recommend it if you are not sure what you are doing.

[beamrider]

Did a battery pull, and let it set for a little while, all is well now.  What a pain in the ass, it should have a reset button somwhere.......

Thanks for the help guys!

[Visus]

Did a battery pull, and let it set for a little while, all is well now.  What a pain in the ass, it should have a reset button somwhere.......

Thanks for the help guys!

Whoa what happens to the units that are out there and sealed using lipo when this happens.    
If using pin 1 to ground can a n/o 50ma tact be used as a reset?

[mamu]

Next time, just vape the charge off, then intermittently press the fire button til the screen blanks out, then charge the batt. 

A lot easier than opening up and disconnecting the batt.

[CraigHB]

I design a reset button into my mods.  Though, I've never had to use it other than to reset the hit counter (it does double duty that way).

I remember reading about MCU and programming and design where a professor once stated, always design a hardware reset into your design no matter how stable you think it's going to be.  At some point you'll need it and probably at the most inconvenient time.

[Breaktru]

I design a reset button into my mods.  Though, I've never had to use it other than to reset the hit counter (it does double duty that way).

I remember reading about MCU and programming and design where a professor once stated, always design a hardware reset into your design no matter how stable you think it's going to be.  At some point you'll need it and probably at the most inconvenient time.

Agree. Smart professor

[beamrider]

This unit is "sealed" as in, internal lipo packs, using evolv usb recharge board.  So I took it apart, de-soldered one of the batt legs, and drained the battery (cause wouldn't you know it, the pack was fully charged when I noticed the unit was screwing up), then reconnected the pack.  Complete pain in the ass, and from now on, I'm going to stick a tact switch in there for a pin 1 ground short solution.

I like the dna20, but it lacks a LOT of features.  I'd like to see it with a reset button on board, and an option to dim/shut off the display, to conserve battery life.  Plus, an option to lock the wattage, and not lock the entire unit, would be nice.

[e-smoky]

In posts above it was said that using pin 1 to ground will reset the device.
Did anyone successfully install a reset switch to DNA20D board?

For your info i found next:

http://www.forum-ecigarette.com/discussions-generales-autour-des-mods-f480/evolv-dna-20d-analyse-du-module-t102518.html#p2030610

and according to the diagram of chip LPC1313F, pin 3 is the reset pin
http://www.ic-on-line.cn/view_online.php?id=1705434&file=0354\lpc1311fhn33_2877510.pdf  ( see page 8 ):
RESET/PIO0_0     PU RESET
External reset input with 20 ns glitch filter. A LOW-going pulse as short as 50 ns on this pin resets the device, causing I/O ports and peripherals to take on their default states, and processor execution to begin at address 0.

Regards

[Visus]

IF you look at the different revisions of the chip it moves from 3 to 2 for reset and the evolv revision is not shown  on the datasheet..

Mamu method is best, those traces are tiny and in a tight space

When I build mine I am using a bullet connector on one leg if I use lipo's,  I know Im using lipos but I might not..

Nice find but Break has not given one wrong info to any I yet so I would trust what he says

[Breaktru]

I stand corrected. The DNA 30 and DNA 20 uses the LPC1313F microcontroller. Pin 2 is the RESET.

[Visus]

OMG what does this mean Break
I gotta rethink things now
Says pin 2 as well on the datas,  so confusing it looks like the dna uses the 32 pin  which is reset on 2 the 48pin is reset on  3
 

[Visus]

Its definitely the 32 pin on the dna in that picture maybe the dna30 uses the 48 pin package

once again this is fun

 

pins 2, 3, and 9 are resets woot cannot miss if leet a tact in..

[Breaktru]

Its definitely the 32 pin on the dna in that picture maybe the dna30 uses the 48 pin package

once again this is fun

 

pins 2, 3, and 9 are resets woot cannot miss if leet a tact in..

Yes you are correct the LPC1313F 32pin is reset on Pin 2.
It's a tight squeeze to get a soldering iron between the smd resistor and the microcontroller. I think only a skilled surgeon should attempt it. Or perhaps Craig.

[CraigHB]

Even if you can solder a wire to the pin (which I don't think I would attempt myself), you can have issues tying tactiles to MCU reset pins.  Reset inputs can be sensitive to noise.  Ideally, you want some caps and resistors on the reset pin to filter any noise.  So, throwing a switch on the pin may cause more problems than it solves.  That's probably why there's no pad on the board for an external reset switch.  Allowing the user to add one could cause problems and the lack of one saves a lot of room on the board. 

Even if noise is not an issue, you need to know how the reset pin is wired.  Reset pins are tied to ground or power usually through a resistor depending on the MCU.  There's a few ways the reset pin could be wired so just throwing a switch on there blindly is not a good idea.  Doing that carries the risk of shorting the circuit and damaging the board.

I believe the design intent for the DNAxx is a tube where an MCU reset is only a matter of replacing the cells.  For non-removable cells, a power switch or a connector that makes it easy to disconnect the battery would be the easiest and best thing to do.  Though switches that can handle those kinds of currents are bulky so that can be a problem.  Other than that, a reset requires draining the battery low enough to force one as already mentioned.

One other possibility is a software reset built into the program.  I've done projects before where a software reset can be initiated by a combination of button presses.  I don't typically do that, I usually use a hardware reset, but I have before.  That may be the case for the DNAxx and it would be an easy way to deal with the issue of the program failing to run properly.  You'd have to find out from the maker if there's a software reset available.

[Visus]

Mamu's method is called (POR)  Power On Reset

Reset
Reset has four sources on the LPC1311/13/42/43: the RESET pin, the Watchdog reset,
power-on reset (POR), and the Brown-Out Detection (BOD) circuit. The RESET pin is a
Schmitt trigger input pin. Assertion of chip reset by any source, once the operating voltage
attains a usable level, starts the IRC and initializes the flash controller.
When the internal reset is removed, the processor begins executing at address 0, which is
initially the reset vector mapped from the boot block. At that point, all of the processor and
peripheral registers have been initialized to predetermined values.

— External reset input with 20 ns glitch filter. A LOW-going
pulse as short as 50 ns on this pin resets the device, causing I/O
ports and peripherals to take on their default states, and processor
execution to begin at address 0

It seems going to ground would be sufficient.  Im not sure but learning here how to read these sheets..

I looked up schmitt trigger those things cost a bit lol so to save on build, POR  tube mod woot

[CraigHB]

MCU makers differentiate the type of reset, such power-on, brown-out, software, etc.  However, they all accomplish the same task, that is reset the MCU's program counter to zero which initiates a software reboot.  In some cases, the type of reset can make a difference, but for a program that has arrived at an indeterminate state, a reset is a reset.  It's actually kind of hard to get an MCU program to do that so I'm a bit surprised it's happening for the Evolv board.  Computer programs do that all the time, but MCUs use only a single thread so it's not that common for it to fall off its track.

[beamrider]

Crap, happened again last night, only this time, it's reading a resistance of 0.0?.  This time, I'm going to just vape it off till it's dead......lol

Damn BBS keeps converting my ohm symbol to a question mark....>.<

[CraigHB]

Damn BBS keeps converting my ohm symbol to a question mark....>.<

Breaktru explained the reason in another post, but the special characters don't work in this forum.  I'm afraid you just have to spell it out here.