Programming Problems

D

D396

Senior Member
I am experiencing a problem programming my PICAXE-18x and would appreciate any Suggestions on potential fixes. Here is the summary:

Configuration:

1) PICAXE programming editor v5.2.2 running on IBM T40 laptop with Windows XP
2) AXE027 PICAXE USB download cable
3) PICAXE-18 Standard Project Board CHI030
4) PICAXE 18X microcontroller
5) 7805ct 5V voltage regulator circut on solderless bread board

With this configuration setup, I am unable to download any program to the PICAXE-18X.

The error I am receiving is the following:

"ERROR- Hardware not found on COM 2"


I have tried two different 18x's as well as two different cables and boards
But the problem still persists. I also tried it on a hp desktop running vista.

Have checked the com ports and they appear to be configured correctly. Have also performed
The "test" under the "serial port" tab on the options window. That also checks out fine.
During the test, when the LED is off, the voltage at the serial-in pin is -0.1 mV.
When the LED is on, the voltage at the serial-in pin is +2.3 V.


I have tried every suggestion given on the Error window but still no luck.
This message occurs regardless of which COM port the PICAXE is using.
 
B

BeanieBots

Moderator
The voltage on the serial pin not high enough. That's why it won't program.
The big question of course, is why is it so low.

What is the voltage on the download socket side of the 22k resistor when the serial pin is at 2.3v?
 
D

D396

Senior Member
resistor voltage

The voltage on BOTH sides on the 22k resistor is 2.346 V. It must be a defective resistor but the thing i don't get is that i have two different boards and nether of them work:confused:.
 
Technical

Technical

Technical Support
Staff member
Take away the breadboard/regulator and just try 4.5V from 3xAA batteries on the CHI030. See if this then works.
 
E

eclectic

Moderator
D396 said:
The voltage on BOTH sides on the 22k resistor is 2.346 V. It must be a defective resistor but the thing i don't get is that i have two different boards and nether of them work:confused:.
Click to expand...
I've just run a test on the CHI030 board. HP desktop.
4 x NiMh v= ~5.1v

4.84v on PE Serial test

I followed BB's suggestion. 4.84 next to 22k res
All OK

What's your voltage on the + terminal of the CHI030?

e
 
hippy

hippy

Technical Support
Staff member
What about as per Technical's suggestion of using 3xAA batteries ?

And yes, 3xAAA should work equally as well.
 
C

cvrwy

Member
Interesting discussion.........

I connected one of my 28X1 chips, and this is what I get for voltages..........

pin 8 - grd - 0 volts (obviously)
pin 7 - serout - continuously varies from about 0.2v to 2.6v
pin 6 - serin - 0v ( this is the lead connected to the 2k2 resistor)

This is with the editor fired up and verified that it sees the 28X1.
All is well..........
 
C

cvrwy

Member
I should add that I too am using the AXE027 USB cable.......
Also, at the moment, my 28X1 does have a running program on it.
I do not know if that has anything to do with the serout pin having the varying voltage.
 
D

D396

Senior Member
I just remembered something it worked the day i first got it then since then it has not worked.
 
E

eclectic

Moderator
D396 said:
I just remembered something it worked the day i first got it then since then it has not worked.
Click to expand...
So, what has happened since then?

Have you changed the board?
Added / subtracted components?

Done "things" with different voltages?

e
 
D

D396

Senior Member
no i have not changed a thing.that's the weird part. when it first did not work i bought a new cable, board and 18x but that did not work so i posted this thread.
 
C

cvrwy

Member
You said that you got another cable, that could mean that your "com" port changed. In the editor, go to "Options" and then "serial port" and see if you have another com port available, it would be white rather than grey. If you do, try it.......
 
B

BeanieBots

Moderator
Ok, 2.3v on BOTH sides of the 22k does NOT mean a defective resistor.
It does however suggest a defective USB cable.
Do you have a 'scope? If yes, then check there is not a waveform on it.

If no, then try this. (poor man's 'scope)

On the socket side of the 22k when it's at 2.3v, connect an LED via 1k resistor to ground. Does it light?

Then, without changing anything else, move the LED's resistor to the supply rail and move the LED's cathode to the point being checked. (ie the 22k at the socket end).
Does it light?

If it lights on both occaisions, then with the LED on a longish lead, shake it as fast as possible. Do you see a continuous line of light or is it broken up?
 
D

D396

Senior Member
I only have a multimeter. it only lights when the LEDs resistor is in the supply rail and the cathode is at the 22k resistors socket side
 
Last edited:
B

BeanieBots

Moderator
Also please do this.
With the USB lead plugged into your computer but NOT connected to the board.
Put the 0v of your meter on the very tip of 3.5mm plug and the +ve of your meter on the middle ring.

Now go the PE USB test screen.
What is the voltage with the screen green LED OFF?
and what is it with the screen green LED on?
 
B

BeanieBots

Moderator
Sorry, but that's a faulty USB cable.
What does the other one do. (not plugged in to the AXE).
 
Last edited:
hippy

hippy

Technical Support
Staff member
the voltage with the LED off is .07 volts the voltage with the LED on is 2.6 V

This is very peculiar. The USB output appears to be behaving at it should but not producing the expected voltage. It looks like the USB cable is faulty or has been damaged.

Do you have another PC to try the USB cable with ( preferably a desktop system ), or can you use a friend's PC to try ?
 
A

Andrew Cowan

Senior Member
It may be worth plugging the USB cable into another USB port, and reintalling the drivers again. It could be something went wrong in the driver installation process.

A
 
D

D396

Senior Member
ive tried it on two different pcs and on two usb ports on each PC with two different drivers and it still id not work
 
J

Janne

Senior Member
I wonder if there is a problem with quality control concerning these usb cables. I have the exact same problem with my usb cable axe027, not enough volts in the serial pin.

I tried to contact rev-ed for RMA but they don't answer my emails :(
 
T

tiscando

Senior Member
Faulty USB cables?

Janne said:
I wonder if there is a problem with quality control concerning these usb cables. I have the exact same problem with my usb cable axe027, not enough volts in the serial pin.
Click to expand...
Erm, I am going to get a usb download cable later, and on reading this thread, I too became somewhat concerned about the picaxe usb cable. :confused: Could anyone come up with an explanation about how to prevent this 'low voltage' problem ocurring to my first USB download cable?
Right now, I am using a serial rs232 cable connected to my 5-year-old Emachines computer with a faulty 2.6GHz celeron processor only at like 1.5GHz at the moment. I typed up this thread using a new fujistsu laptop with a Pentium M 1.73GHz, which is at full speed at the moment.
 
B

BeanieBots

Moderator
This can't be a very common problem or we would have thousands of posts about it.
I can only speak from sample of one and have not had any issue.
Mine puts out spot on 0v and 5v.

When you get your lead, test it. If it's duff, take it up with the supplier.

I'm not making any accusations here, but that 3.5mm jack is tempting for some numpty to stick it in a speaker out socket thinking it's an audio to USB download for their HiFi/iPod. That wouldn't do it any good at all. Nor would connecting any of the pins to a 12v supply, so they are possible to damage.

If at all possible, try it on a "known to work" PC as apposed to one which has had the same drivers installed by the same person and never actually ever been seen to work OK. Alternatively, try a known working USB cable on that PC.
 
T

tiscando

Senior Member
BeanieBots said:
This can't be a very common problem or we would have thousands of posts about it.
...
When you get your lead, test it. If it's duff, take it up with the supplier.

I'm not making any accusations here, but that 3.5mm jack is tempting for some numpty to stick it in a speaker out socket thinking it's an audio to USB download for their HiFi/iPod. That wouldn't do it any good at all. Nor would connecting any of the pins to a 12v supply, so they are possible to damage.
Click to expand...
Okay BeanieBots.
p.s. When I first got the serial download cable and 2 miniature 3.5mm stereo jacks, the jacks didn't fit onto my breadboard, so I sheathed the cable's sheathing about 5cm away from the jack plug, and cut and sheathed the cores (finding out that the red is TXD, brown is RXD, and black is GND), and clamped them onto a 3-way PCB terminal block the same way round as the configuration of the molex header. I could easily push in and pull out the terminal block into and out of my breadboard, and it worked well since then.

After Xmas, I crimped on the molex header. I kept the stereo plug intact with the cable mesh, and connected. This worked well also.

When I get the USB download cable, I will buy proper 3.5mm jack sockets with it. ;)
 
B

BeanieBots

Moderator
I've made up a little adapter with the "enhanced" parts of the download circuit. The cable plugs into that, then that uses a 3-pin "servo" connector to connect to the "standard" download circuit. I use a different pin assignment to the "molex" pinout, so that reverse connections don't cause damage. Then all I need on the board is a three pin header.
Only problem this has ever caused is when I publish a circuit and people pick up the "wrong" pinout for the download connector.
 
W

westaust55

Moderator
USB cable problems

Like BB I have never had a problem with my one and only AXE027 USB cable.

I wonder if those who are having problems with AXE027 type cables have other devices conencted to their USB ports that are drawing power.
The power available form USB ports is renown for being light on and volt drop within the PC could be the issue.
 
K

kevrus

New Member
by BB
I've made up a little adapter with the "enhanced" parts of the download circuit. The cable plugs into that, then that uses a 3-pin "servo" connector to connect to the "standard" download circuit. I use a different pin assignment to the "molex" pinout, so that reverse connections don't cause damage. Then all I need on the board is a three pin header.
Click to expand...
Now that is a good idea...I often use a 3pin molex, but still keep the download circuit on board, good for a bit of space saving (and a few penny components)
 
B

BeanieBots

Moderator
It would be very valueable information if D396 would get back to us with how his other cable behaves and if either of his cables work on SOMEBODY ELSE's PC who has a working PICAXE setup.
I'm very concerned about the "tried with two different drivers" comment.
Also, 2.3v ~ 2.6v is about right for a "signal" being sent if measured with an averaging DVM although the results of the LED tests I requested suggest a burnt out upper totempole half on the USB chip.
The output is 'protected' via a 100R resistor so it should be able to handle shorts. Excess voltage (~12v) (except for static discharge) would normally burn out the resistor before the transistor drive section. That would give different test results, so this is quite confusing.

3 people reporting the same problem is by no means a large failure rate but does warrant further investigation as the symptoms appear to have a common cause. The chip itself is in very common use and has no 'known' issues or weaknesses reported.

Interestingly, the reported low voltages would in most cases be enough to program the PICAXE chips which do not have ST type inputs, so maybe this is more common than originally thought but has not been observed as a problem due to other reasons such as PICAXE choice and supply type used. 3 X 1.5v being more likely to program succesfully with a lower serin drive voltage.

We can only wait for more scientific test results from users or hope for a comment from Technical.
 
D

D396

Senior Member
I contacted the retailer and they are going to send me a new one and test the old one on their pc I see what they say
 
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