V3 COMMS problem

[KITT]

Hi all,

I friend's given me his V3 board to check over as he can't get it to work. I've tested it and can't either. I'm using an older laptop with a proper comm port and cable which I know works fine as it communicates with my Megajolt V2 no problems.

I've tried the Hyper-Terminal test and the mjdiag.exe one, and both don't work. I tried loading the bootloader to it which sort of works. When you run hc08sprg it waits for you to plug in the Megajolt. As soon as I do so it starts counting up but never stops.

I've checked all the voltages for the major components and soldering which all look fine, so really am stuck now.

Any ideas folks?

cheers

Matt Dearden
http://www.cate1.co.uk/megajolt

[brentp]

KITT, If you have a functioning unit you might want to switch the processors to see if that makes a difference.

Sometimes the solder joints may look good on the surface but might hide a flaw. Since you're approaching the problem from the aspect of serial port communications, focus on all the parts around the MAX232- especially the 0.1uF capacitors. You might want to re-heat each solder joint on the IC and corresponding components to absolutely make sure they have a good connection.

Unfortunately, the fact that you started re-flashing the chip might have complicated things. Did it indicate that it was actually writing to the part?

Plus, while programming, the hc08sprg.exe only counts from 0 to 100%, so it's unclear to me how it could count endlessly. What was it actually counting?

Hope this helps,
Brent

[KITT]

Hi Brent,

hc08sprg.exe outputs as follows:

Waiting for HC08 reset ACK...

then when you plug the Megajolt in it ouputs:

received 0x00 (off-key).
Calibration break pulse sent. Count: 22

and that count just keeps going up.

The processor on my ECU is hard soldered in so I don't fancy swaping them incase I ruin mine too.

My mate mentioned that he actually ordered it from you direct, so I'm most supprised it's not working as I know you test them before shipping.

I'll try re-soldering everything and see if that helps.

Matt Dearden
http://www.cate1.co.uk/megajolt

[KITT]

I've re-soldered all the components but it's still not working (

Any other tests that can be done?

Matt Dearden
http://www.cate1.co.uk/megajolt

[brentp]

Ok- Did you try my other suggestions in my original reply? There were a couple of other things to try.

[MartinM]

Hi Matt

If you remember, I emailed you about dipping my toe into MJLJ a few months ago and your reply prompted me to get involved - and I'm really really pleased with mine. It's made a whole load of difference to my rally car. Thanks!

I think you're gonna have to try another MAX232 and/or another processor There's no harm in having spares, even if it doesn't turn out that the originals are faulty. Maplin do the MAX232 and I'm sure Bill Shurvinton can help you out with a processor.

On one point, I make sure (in the three MJLJs I've built) that I use IC sockets for all 3 ICs. I'm not sure why Brent solders the MAX232 in place on the board (Brent?). Maybe it's the processors and darlington array that are expected to break most!

In-situ mounting of an IC is fine if you've some sort of flow-soldering machine doing the soldering, but DIY soldering (and re-soldering) of an IC in-situ is definitely not recommended (in terms of overheating and destroying the IC), unless you're a bit of an expert.

Using IC sockets obviously solves this - they can, within reason, get really hot as you solder them in, but it doesn't matter.

If you're worried about ICs shaking loose from a socket:
- I've never seen one do it
- a dab of silicon sealer at the ends, covering the IC and the socket, will stop it happening


HTH, Martin