PICAXE IC become clean!

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Pekari

Senior Member
I did the circuit board with PICAXE 18X and have used it several days. Today it works some time but then program stopped. I turn off a device and then turn on but it doesn't start any more. Then I load program again to IC and then it works again!

Why is that?

Is to someone happened same case?
 
B

BeanieBots

Moderator
Sounds like you have either one or both of the serin or reset pins floating.
Serin must be held low and reset must be pulled high.
 
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Pekari

Senior Member
Thanks, that's right; I haven't connect serial in to ground!

Now it is connected and I hope it works better.
 
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Pekari

Senior Member
Is the IC damaged?

Now it happens again!:mad:

I have connected reset to Vsupply and serial in to GND (0V = -) like in order, but IC become empty again!:(
I load a program to IC and it works again normally.

Notes:
Vsupply = 4.3V
Serial out is floating.

Which else could do that?
 
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BeanieBots

Moderator
A PICAXE simply can't suddenly become "empty".
Double check your circuit.
It might be that when you remove the programming cable the serin pin is left floating.
Does this problem only happen when you remove the cable?
 
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Pekari

Senior Member
I have get this problem 2 times and IC is always be in the circuit where is no serial cable connection and those pins are tied where it must be, without a resistor.

This is start code:
Code: 
pause 200 
low 0 low 1 low 2 low 3 low 4 low 5 low 6 low 7
pause 300
high 0
pause 200
low 0
Output 0: Transistor are driving a relay and I can hear if program start. If program doesn't run I can't hear sound of relay.
 
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BeanieBots

Moderator
So that will pulse a relay on for 200mS when power is applied and then do nothing.
When you are testing this, are you sure the power supply is going right down to 0v before powering up again?
 
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Pekari

Senior Member
I have a LED in board and I can see if power is off or on. Yes, I wait while before new start.
That code is start of long code but it must use a relay in start.
 
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crossthreaded

New Member
I have had exactly the problem you describe. I'm operating from a regulated battery supply. The batteries also supply some servos unregulated power. I find that if the batteries are less than about 1/4 capacity, the 18X sometimes loses its program.

My circuit has a possible bit of bad practice in that the picaxe to servo lines are not buffered or protected. I've bought the diodes to add protection but not fitted them yet because the whole thing is soldered and rather small and fiddly to work on.

So, you are not alone. I have a picaxe 18x which sometimes forgets.

The only additional information I can offer is that it doesn't appear to be a hard latch-up problem, because following an application of power where the program vanishes, without removing power again, the picaxe will respond to a program download correctly.
 
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Pekari

Senior Member
Always when I have done a circuit board, I have make a 5V regulator and serial diode which let down a voltage and never get this problem before.
If I take away that diode, will this IC suffer of 5.0 V voltage?
 
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hippy

hippy

Ex-Staff (retired)
In both cases there is a physical device ( relay and servo ) which both require high currents and can generate significant electrical interference which suggests the problem may be related to that.

PICAXE's can be operated from a 5V supply.
 
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Pekari

Senior Member
I bring up it to 5 V. Doesn't explode yet.:D
How much these PICAXE-chips can trust? I mean, can this program disappear or alter within some time or can it run for years?
What if I doesn't use chip for years, will this program still be in that IC and it works when I take it (some device) to use without reload a program in?

If some ask me, I say: It can disappear any time, even in the middle of running, I have 2 event.:(
 
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ciseco

Senior Member
Pekari, I really think you must be doing something to produce this effect. It's never happened to me and I've had lots of picaxes that have been programmed many times.

Just did a quick search on google, they should keep their program for approximately 40 years.

Miles
________
BMW N45 picture
 
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hippy

hippy

Ex-Staff (retired)
If programmed correctly the PICAXE should be good for 40 years, probably longer, but that doesn't cater for external events which affect it. A direct lightning strike will almost certainly curtail its lifetime and other events of a smaller scale can have less, but equally corrupting, effects. There's no guarantee of anything, but under 'normal circumstances', as vague as that is, there should be no problems.

Losing a PICAXE program regularly suggests there's some specific event occurring or leading to that. The problem is in identifying what that is.

One thing you can try is using a different PICAXE. If that works then you may have identified a problem with the one which loses its program. If both exhibit the same loss then it becomes less likely that it is a problem with the PICAXE itself.
 
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BeanieBots

Moderator
The command "poke" can cause serious problems when not used properly but I'd be surprised if you could wipe a PICAXE with it.
Incorrect switching of inductive loads (such as a relay without clamp diode or poor layout) can "crash" a PICAXE but again, it wouldn't wipe the program.

I'm no expert on the deeper workings of EEPROM, but programming at the incorrect supply voltage (too high or too low) can significantly impare data integrity, especially if there are any factors such as partial damage caused by power spikes such as those one would experience when switching inductive loads that have not been correctly clamped.
 
hippy

hippy

Ex-Staff (retired)
Pekari said:
Which kind of bug in program will lose whole program or make it inoperative?
Click to expand...
Sorry; it's my mistake for the confusion. Programming means many different things and in this case I meant the process of placing ( "burning" ) the program code into the memory. If this is done with the wrong supply voltage or with the wrong algorithm the integrity of the program code will not be as reliable as when done properly. Glue may hold something to a wall for a long time but that will often fall sooner than it would if the recommended nail were used.
 
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Pekari

Senior Member
Thanks.
I haven't used a command "POKE".
I use 4,63 Volt when I load a program to IC and I suppose it's good level.
In the circuit, I have in parallel a relay and diode.

Maybe that problem is about that IC. I changed it to the other and I am testing it now.
 
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Pekari

Senior Member
I have a Picaxe LCD-screen CTR19K 0511 and it have a problem with clock.
When I purchase it, alarm setting doesn't work. Then I bring back it and they change a Picaxe-IC PIC16F819. Then clock works but alarm setting doesn't work.
This time I haven't use the screen a half year and then I test it:
Now even clock doesn't work any more. So I can't use that clock for anything because I can't trust it.
I can write a message on screen and use it.
 
hippy

hippy

Ex-Staff (retired)
All PICAXE's are as reliable as the others when used in accordance with manufacturer's specification.

As to the problems with the LCD that seems to be a separate issue and I wouldn't consider that as evidence that there are systemic problems with Rev-Ed product.

We would need to know more details about exactly what does and does not work to diagnose the problem you are having with the LCD however, attempting to solve that issue seems to be pointless until the issue with the PICAXE itself can be resolved.
 
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Rickharris

Senior Member
Pekari said:
I bring up it to 5 V. Doesn't explode yet.:D
How much these PICAXE-chips can trust? I mean, can this program disappear or alter within some time or can it run for years?
What if I doesn't use chip for years, will this program still be in that IC and it works when I take it (some device) to use without reload a program in?

If some ask me, I say: It can disappear any time, even in the middle of running, I have 2 event.:(
Click to expand...
We use 100's of picaxe 08s 08Ms and others I have never seen one loose it's programme. This must be an external effect from your circuit or some other issue.

Go back to something very simple - Picaxe + LED for example to confirm it keeps its programme.
 
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Pekari

Senior Member
I have real time clock IC in that screen.
As I write, that clock doesn't work any more, so I can't test it.
This command doesn't work even when device was new:
Code: 
serout 1,N2400,(253,9,"00:00:10        ")
command ...253,8... worked when I test it but even that I can't trust 100% when I use it, about 9 month ago .
After that I haven't use it. Battery give now >3 Volt.
 
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W

westaust55

Moderator
The DS1307 needs a supply voltage between 4.5V and 5.5V,
so a voltage >3V but still less than 4.5V is doubtful for DS1307 RTC operation.

I assume you have the DS1307 installed on an AXE033 LCD display?

With respect to setting the time on the DS1307 from the PICAXE in BASIC, have you tried to first set the time and then the alarm.
If the clock has been de-energised with no battery backup then it needs to be set before the clock will start operating/timing.
Code: 
SEROUT 1, N2400, (253, 0, "06/10/08 00:00  ")
 
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P

Pekari

Senior Member
westaust55 said:
The DS1307 needs a supply voltage between 4.5V and 5.5V,
so a voltage >3V but still less than 4.5V is doubtful for DS1307 RTC operation.
Click to expand...
Why in this board is originally 3V battery (1xCR2032):confused:

Thanks, I get a clock run.

Still same problem: command
Code: 
serout 1,N2400,(253,9,"00:00:20        ")
doesn't work, why?

From the first time when I buy this LCD, it reseted sometimes and it has done it again even through the IC is changed.

Can this problem be caused by low voltage?
Why they put to this 3V battery?
 
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B

BeanieBots

Moderator
The 3v is for BACKUP only. When running on the backup battery, it is not possible to 'talk' to the chip. It needs 5v to be able to read/write to it.
 
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Pekari

Senior Member
Thanks, now I know what RTC means.
Of course I have apply higher voltage to screen when it is connected and talking with PICAXE.
Does anyone know from where depend that command ...253,9... doesn't work?
Is it about that IC PIC 16F819?
How about that resetting problem?
This command doesn't work also:
Code: 
serout 1,N2400,(253,10)
 
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Pekari

Senior Member
Now this problem is solved!

In my circuit I has a bug. I was tied RESET to + without a resistor.

This resistor is VERY IMPORTANT!
 
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