Power cycle, reset

[Russell]

Hi

I've been building a TouchDRO using a secondhand MSP430G2ET and a cheap Bluetooth adapter. It all appears to work with a stable connection to my phone although I haven't yet tried connecting the scales.

I've been very impressed so far and I'm grateful for you making it available.

I'm having a problem - possibly with the power supply but I'm not sure about that.  The problem is that I can't get the "heartbeat" LED flashing without pressing the reset button.

I've tried different phone chargers and I've tried turning off and on again, both by switching the mains and disconnecting the USB lead.

I noticed that the oscillator "jumpers" on the launchpad had been altered and put those back to the default position.

None of this has made any difference.

I'd welcome any suggestions, as this has definite implications for building an enclosure.

Russell

[NormanP]

Hi Russell,

I have found the same problem - to the point where I have added a small reset switch and a heartbeat LED (required pins are on the MSP430) to the casing to enable quick resets.

Occasionally the unit starts up ok - most times I need to use the reset button.

[Russell]

Hi Norman

Thank you for that. It reassures me that there's nothing fundamentally wrong.

I'll have a look at the pins. I assumed I'd have to add some leads to the mounting of the reset switch.

Thanks again.

Russell

[Russell]

This morning I sorted out all the parts to add a remote reset switch and a remote LED.  I connected them together on the bench using croc clips and powered it up.  Heartbeat LED started flashing and did every time I powered it up.  The reset switch worked as well although I didn't need it.

I thought that was quite an unexpected result.

Russell

[NormanP]

Hi Russell,

That's good news. If you find out what the cause was, can you let me know.

Cheers,
Norman

[Russell]

Hi Norman

I've very little idea about the cause.  I can say that the extra reset switch makes no difference as I've tried it without that.  My conclusion so far is that replacing the onboard green LED and 390 ohm resistor with external ones fixes the problem.  I'd guess that the longer leads might increase the capacitance but it would be a tiny amount.  I have more experiments in mind.

Russell