TROUBLE DOWNLOADING

4jaba6

New Member
Have been trying to download a medium size program that is slightly complicated ( but not overly ).
It downloads ok on another project board.
I also downloaded a smaller blink led program and it downloads ok and works fine.
Back to the problem program:
It apparently downloads ( or almost downloads ? ) because it does not run and there is a msg. in lower rt. on screen in download progress box that says
"Debug...Waiting for Data..."
My first inclination would be bad 20M2, but it does run the smaller led program.
any thots or ideas???

Not to complicate things but almost every download, I have to do a "hard reset" by turning on power and then clicking "program download" and then quickly shut off power and then quickly turn back on!

TIA ( Thank you in Advance )

JB
 

AllyCat

Senior Member
Hi,
It downloads ok on another project board.
Also a 20M2 ? That suggests a Hardware issue, so the first questions are; What is the power supply (voltage), are suitable decoupling capacitors (100nF and/or 10uF) connected close to the supply pins (Legs 1 and 20) and is the programming circuit (10k + 22k) definitely wired up correctly? Of course it might be a damaged PICaxe, but that's quite unusual and there are plenty of other tests to be done before assuming it is faulty.

In view of the "Debug ... waiting.." message, does your program use a DEBUG command? Or a SERRXD command, which generates an "invisible" DISCONNECT that requires the use of the Hard Reset procedure. Incidentally your Hard Reset procedure is not fully correct. Strictly you should start with the power OFF (perhaps even briefly short-circuiting the PICaxe's supply to ground pins) , start the Download and then apply the power within a few seconds.

Cheers, Alan.
 
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4jaba6

New Member
Hi,

Also a 20M2 ? That suggests a Hardware issue, so the first questions are; What is the power supply (voltage), are suitable decoupling capacitors (100nF and/or 10uF) connected close to the supply pins (Legs 1 and 20) and is the programming circuit (10k + 22k) definitely wired up correctly? Of course it might be a damaged PICaxe, but that's quite unusual and there are plenty of other tests to be done before assuming it is faulty.

In view of the "Debug ... waiting.." message, does your program use a DEBUG command? Or a SERRXD command, which generates an "invisible" DISCONNECT that requires the use of the Hard Reset procedure. Incidentally your Hard Reset procedure is not fully correct. Strictly you should start with the power OFF (perhaps even briefly short-circuiting the PICaxe's supply to ground pins) , start the Download and then apply the power within a few seconds.

Cheers, Alan.
Alan,
Thank you and papaof2 for your suggestions.
am trying to work on these this weekend.
Other responsibility's keep getting in way but eventually....

Thanks again

JB
 

erco

Senior Member
When in doubt, swap in a new Picaxe. This has saved my bacon several times when mysterious things happen on download or in operation. If a factory-fresh Picaxe works, I put the potentially damaged original chip in a reject pile, with best intentions of following up "someday".
 

inglewoodpete

Senior Member
When in doubt, swap in a new Picaxe.
In my experience PICs, and consequently PICAXEs, are tough little beasts. I have used over a hundred PICAXEs (and numerous PICs) and done thousands of downloads to them.

I have had three failures and all three were from applying the wong voltage to them. Two were from me applying 12v to a supply or input pin on a breadboard and the third failed when a switchmode regulator went wayward and the supply voltage crept up to 8 volts. So, for me, the biggest risk is for overvoltage being applied. If you keep any nearby voltage below 5.5 volts, you are unlikely to have a PICAXE fail.
 

neiltechspec

Senior Member
Not as many as above, but I have used tens of Picaxe's with hundreds of downloads,
from 08M2 to 28X2.
Only ever had one fail, entirely down to me giving it 12v supply !. Picked up the wrong 'wall wart',
12v instead of 5v.
 

erco

Senior Member
Yes, my failure rates are surely higher because of hardware issues (AKA cruel & unusual punishment). I teach Picaxe classes, and of course students make wiring errors all day long in solderless breadboards. In my own projects, I scratch-build every board and experiment as I go, trying shortcuts and interfacing new hardware on the fly, learning what works and what doesn't. Picaxes are amazingly robust chips even in my wicked hands, so they should last much longer with proper care.
 

Technoman

Senior Member
Thousands of download done by students. Sometimes, a hard reset was necessary. The encountered hardware problems came from some broken cables (AXE026) and damaged sockets (RS232 port/Picaxe socket). The students were doing some programming, the hardware part being restricted to properly connect a sensor or a motor. Few did some experiments with MCU chips. I found theses chips very reliable and don't remember having to replace one. Removed later from boards they are now in a drawer, mainly 20M, waiting to be tested. If the chip is able to run a program, it's a good start then what about the I/O? I have never seen a post concerning a short I/O testing.
 

erco

Senior Member
Removed later from boards they are now in a drawer, mainly 20M, waiting to be tested. If the chip is able to run a program, it's a good start then what about the I/O? I have never seen a post concerning a short I/O testing.
Tracy Allen is a guru on the Parallax forum. In the post below, he shares a clever, tiny program to test I/O pins on a Basic Stamp, which is somewhat akin to a 20-pin Picaxe. With some tweaking, it could be used to test Picaxe I/O pins.

 

4jaba6

New Member
4jaba6 sorry for the hijack. Any news to report?
erco and others,
No problem with the supposed "hijack"; enjoying all the discourse and informative conversations

In fact, am hijacking my own topic.
I subsituted a similar board to the one I was having difficulty with because it works.( easy way out ).

Am attempting to use 20M2 to control motors using L293DNE.

However, a new problem ( my hijack ).
This new board ( call it board "A" ) will not run the motors on my project.
I am using circuit suggested by Inglewoodpete several months ago.
Topic: 5V Source for SN754410 "ENABLE" Pins

I have an exact duplicate board that does work ( call it board "B" ) !?!?!?
I replaced the L293DNE on board A with a new one and it worked but only ONE time and then stopped working!!!
The L293 motor control pins ( 2, 7, 10, 15 ) get the 5 volts from the 20M2 output pins but to not put any voltage on the
motor connections ( pins 3,6,11,14 ).
I am supplying pin 8 motor power pin with 7 volts.
Again, the exact same setup on board B works!

Some thoughts: maybe not EXACT same circuits on the 2 boards/ maybe defective proto board/ maybe there is a more robust L293/
maybe a separate power source for pin 8 on L293/ bail out and go back to SN754410 ???

Thank you for your input/suggestions in advance (TIA ).

John
 

papaof2

Senior Member
A board that only works one time could have been caused the back-EMF protection diodes not functioning.to protect the motor driver chip.
 

Technical

Technical Support
Staff member
Check the part number carefully, only L293D / L293DLE have internal diodes. L293 or L293LE (without D in part) require external diodes, if missing they would fail quickly.
 

Technoman

Senior Member
... only ONE time and then stopped working!!!
In summer time, heat is building up rather quickly then triggering the internal overheating protection of the L293. We had this problem, solved using a heatsink. Have you tried to let it cool down before restarting it?
 

4jaba6

New Member
Thanks to all for your input.

Am using the L293DNE.
As noted it works on my other duplicate project 20M2 and 293 boards.
This project as of yet generates no heat because the codes passed to the 293 from 20M2 do not
generate any motor action.
Due to the various solutions tried with out any success, decided to replace all hardware including a new 293 and also a new proto board.
Have not yet had time to check and see how this does ( too many other priorities ).
After testing this, shall report back to this thread.

JB
 

4jaba6

New Member
OK PROBLEM SOLVED1 ( PROB. SHOULD WAIT A DAY BEFORE PROCLAIMING BECASUSE "MURPHY" CAN ALWAYS RETURN ).

Checked all common leads between 20M2 and L293 and L293. Enables not getting + 5v and consequently the motors not getting power
even though pin 8 getting 7 + volts.
The motor enables on the 293 from 20M2 were getting their 5V.
Rechecked all connections with other ROBO that works and appeared same.
Traced all enable hardware and appeared ok. Decided to remove switch and do direct connection ( no switch ) for the 5v enables and WORKED! Was a bad switch.
Why didn't I test this days ago??? Probably because it was one of least pieces of hardware that to me was suspect.

Thanks to all for bearing with me during this very frustrating period.
 

papaof2

Senior Member
I think anyone who dabbles in electronics gets a bias that it "must" be the active components because those boring resistors, capacitors and switches don't "do" anything. My older Dell laptop doesn't always respond to the power button - but the problem is the button as it works fine if your press it a bit off-center. Yes, I could fix it but that's tiny work which I prefer to avoid. I'll just press the button a second time...
 
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