18X verification error

[BeanieBots]

This has me scratching my head

What is different about the 18X?

I have a project with an 18X. 5v regulated supply. Standard download circuit.
Been working fine for ages. Doing lots of software updates, no problem.
Then I get a few verification errors, but eventually programs.
Now it errors every time.

OK, suspect the 18X.
Move it to AXE090 same problem.
Now convinced it's the 18X, try a brand new one in AXE090.
Same problem.
Must be download cable then. (although firmware check is OK).

Try 08M. Programs fine.
Try 28X1. Programs fine.

Tried another 3 18Xs, all give instant verifaction error when in AXE090 and in AXE110.

Conclusion.
I can program any chip in any board except any 18X won't program in any of the boards.

Open to suggestions.

PS.
Done a re-boot. No change. Everything fine except 18X.
Tried different ports as well.
Verification error on any download attempt to any 18X including clear hardware.
Firmware check works.
All other chips work.

PPS.
Tried uninstall/install of editor thinking maybe 18X specifc file corrupt.
No change.

PPPS.
Dug out old machine. Editor V4.1.5. No USB.
Programs the 18Xs just fine. (so the chips are fine)

So why not this machine and why only 18X a problem?
Why suddenly, was never a proplem before?

 

[Mycroft2152]

The 18x is more sensitive to low serial port voltages.

I have one laptop that would program 08M's fine, but would just not work with 18X's. I ended up by adding a 74xxx series inverter in the serial line.

Brian at Wulfden sells an adapter board and has the schematic on his website.

Myc





Myc

 

[BeanieBots]

I appreciate what you are saying, and will investigate the voltages in greater depth.

However, I've been using the same setup for years without issue. It just suddenly stopped working. Like something broke.
I've even gone as far as warming up and cooling down the USB adapter.

Just tried on a brand new PC. First time install, so no possible residue.
Same problem. All OK except 18Xs. Certainly points to the USB adapter.

 

[hippy]

Try running from 3 x AA batteries; as the +V drops the serial voltage will relativistically increase; that may show if it's a USB adapter voltage problem.

 

[BeanieBots]

Tried that. No Change.
Also tried extra 47k pull-up/down on serin to see if it's threshold thing.
Still no change. Firmware check works under all test conditions.
Attempts to program gives instant verification error on all 18X chips.
All other chips program fine.

Old PC (98SE) without USB adapter still programs them fine.

Something has changed!

Edit:
On USB adapter, no connections +9.72v, -8.94v
At the chip in AXE090 +5.65v, -0.198v
So, doesn't look like voltage problem.
Now suspect PC baud problem, but on TWO PCs! (both XP)
Also tried adding 10k//22k, no change.

 

[BeanieBots]

Problem fixed by replacing USB010 with AXE027.
Driver/USB chip?? Dunno.
Just glad to be programming again.

 

[inglewoodpete]

This suggests a failing USB to serial adapter cable.

I had a look at hippy's PICAXE input type posting and noticed that the 18X has a schmitt trigger input while the 08M and 28X1 both use TTL.

It would be interesting to see if the cable could programme an 18, 18A, 28, 28A, 28X or 40X: these have ST programming pins too.

 

[BeanieBots]

Interesting point about the logic type.
I just tried 2 28Xs. They were fine.
I've only got one 18A and guess what?
It does program but about 1 in 5 gives verification error but it also gives an occaisional error using a 'proper' serial port. It was part of a large batch (20) for a school project. It gave the odd error at the time which is why I have it now. All the others were fine.
The only 28As I have are all "busy". Don't recall ever having an issue with them.

The bit that really has me stumped is that this happened suddenly.
I was just downloading edit after edit of a menu system.
That indicates hardware failure yet 08,08M,28X,28X1 are all fine.