Startup problem of Midio128

[ReinerS]

Hi,

I'm running a midio128 to query the stop-buttons on my organ console and send the data to the Hauptwerk virtual pipe organ software. This has worked great for a while but lately I am getting startup problems:

Most of the times the box seems to lock up during the startup phase. A random number (many times actually all of them) of output pins get set to active (so the LEDs on my stop switches light up) and nothing happens any more. Switching on and off a number of times mostly gets it working after a random number of tries, and once it is working it keeps running stable. I think it may be either the power supply or some interference from the long unshielded cables running to the switches and LEDs.

One thing I would like to try as a work around (or simple fix) would be a hardware reset, but I find no mention of it in the docu anywhere. Is there a pin on the core module one could use for a hardware reset of the PIC? I might be able to get it to work issuing a reset immediately after power on.

Thanks for your help

Reiner

[stryd_one]

It hardware resets every time you power it on and off...

Sounds like you're right though, I'd try disconnecting the modules and see if the core boots without them as a start, and maybe look at the power too..

[smashtv]

Every power supply has a "ramp up" time, some are quite noisy during this start up.

When you cycle the power x times to get it going, are you switching the mains transformer on and off with this switch, or just the input voltage to the MIDIbox from the secondary side?

Give it a try with leaving the mains transformer powered but cycling the low voltage between it and the Core, if the symptoms change look towards the power supply as the issue (you can probably add an electrolytic cap to stop this), if it acts the same look elsewhere....

Also know that a ground loop/path fed by the center pin of J12 MIDI OUT can cause same symptoms in certain setups, you might disconnect your MIDI cables and see if the failure mode changes.  (this is all relative to your MIDI interface on the PC, most simple joystick port MIDI cables will tie the PC's noisy ground rail to the Core ground at this connection, not good!)

Let's see if we can find the cause rather than patching the symptom (cycle reset)  ;)

Best

Smash

[TK.]

There is a hardware reset at MCLR# (PIC Pin 1) which you could try - just tip it to ground.

Maybe it would already help to enlarge the reset time by adding a cap (100 nF or higher) against ground, and to increase the resistor value from 100 to 10k

Best Regards, Thorsten.

[ReinerS]

Thanks for your hints!

I'll try Thorstens suggestion with the cap and resistor change.

Actually I noticed yesterday that a little patience also does wonders here: The midio stays locked with a number of output LEDs on (the LCD backlight dims down a bit, which indicates a power supply problem, but I measure 9V DC going into the core module and 4.99 when measuring the 5V line), but after a while (between 5 and 30 seconds) it recovers again! The output LEDs turn off (in groups, wonder why that is) and then Mios displays it startup message on the LCD and everything is running fine.

So I might just leave it as it is for a while, its quite a hassle to move the organ and open it up.

Best wishes

Reiner

[stryd_one]

Good to hear that it's kinda behaving, although I think it's very unwise to leave it half-broken, which is essentially the same thing as giving it the opportunity to REALLY screw up.

I tell ya what, if it comes back to life so quickly and you never noticed before, I have to say that you might be rushing things a bit!

I think this is #1 on the list of advice given on this board - BE PATIENT :) I don't think I've heard of one singlular issue being solved by rushing, except for maybe pulling the plug on something that's on fire ;)

So does it lock up like that with other applications?