Comments for MightyOhm

Comment on Mac OS X by OS X ATtiny25 Programming Walkthrough | Arduino collector blog

OS X ATtiny25 Programming Walkthrough | Arduino collector blog — Thu, 25 Apr 2013 11:40:59 +0000

[...] If you get any other response, check the troubleshooting notes at the bottom of Jeff Keyzer’s AVR toolchain installation page. [...]

Comment on HSC Santa Rosa closing on May 4th, Closeout Sale starts April 27 by Jeff

Jeff — Sat, 20 Apr 2013 23:55:11 +0000

Mike,

I’m planning to stop by on my way back from Santa Rosa on Thursday afternoon. Hope to see you there.

Comment on HSC Santa Rosa closing on May 4th, Closeout Sale starts April 27 by Mike Butler

Mike Butler — Fri, 19 Apr 2013 13:49:21 +0000

Thanks for posting this, Jeff. Hope to see you there.

Comment on Simple fix for Bus Pirate power supply oscillations by Bus Pirate power supply oscillations – A connected ape

Bus Pirate power supply oscillations – A connected ape — Fri, 12 Apr 2013 21:26:32 +0000

[...] today, I saw that Jeff Keyzer (aka MightyOhm) had posted on his blog about power supply oscillations on the Bus Pirate. The Bus Pirate is one of my go-to tools, and 99% of the time it works as I’d hope, so I [...]

Comment on HV Rescue Shields are back in stock! by Jeff

Jeff — Tue, 09 Apr 2013 20:42:28 +0000

ElectroNick – That is an excellent suggestion – on low pincount parts you often need to take advantage of every IO pin you can get.

Comment on HV Rescue Shields are back in stock! by ElectroNick

ElectroNick — Sun, 07 Apr 2013 18:29:06 +0000

We could also call this an “I/O lines expander” – if you’re not dependent on ISCP, then you can free up the Reset pin and get that 6th I/O line you always wanted (speaking in terms of the smaller chips like Attiny13 that always seem to have one I/O less than you actually need)

Comment on Simple fix for Bus Pirate power supply oscillations by Ian

Ian — Wed, 06 Mar 2013 12:55:42 +0000

Thanks for the great investigation and writeup. I pulled all my Bus Pirate production models and tested them. Take a look here:
http://dangerousprototypes.com/2013/03/06/possible-issue-with-voltage-regulation-on-some-bus-pirates/

I see it in the very old SparkFun Bus Pirate I have, but not any of the Seeed Bus Pirate (though this could potentially effect a number of early v3b Pirates if they were fitted with MIC5205s).

Comment on Bus Pirate v4 oscillates too. Tantalum cap to the rescue! by charliehotel

charliehotel — Tue, 05 Mar 2013 06:43:58 +0000

MIC5205 datasheet says:

The output capacitor should have an ESR (effective
series resistance) of about 5Ω or less and a resonant
frequency above 1MHz. Ultra-low-ESR capacitors can
cause a low amplitude oscillation on the output and/or
underdamped transient response. Most tantalum or
aluminum electrolytic capacitors are adequate; film types
will work, but are more expensive. Since many aluminum
electrolytics have electrolytes that freeze at about –
30°C, solid tantalums are recommended for operation
below –25°C.

Comment on Simple fix for Bus Pirate power supply oscillations by Zeta

Zeta — Mon, 04 Mar 2013 17:51:34 +0000

the easiest fix for me is just to remove the Mic5205 and change it for a Mic5255 or mic5225 or any other regulator that is stable with low-ERS ceramic caps. The Seed buspirates should not have this problem as they dont actually use micrel parts.

Comment on Simple fix for Bus Pirate power supply oscillations by Maxim

Maxim — Sun, 03 Mar 2013 14:28:43 +0000

I also have an SFE Bus Pirate, marked 2/10/2010 which also uses the MIC5205 for the Vregs. I also noticed the output noise and added what I had laying around – a 10uF Electrolytic. Soldered that in and yes it got rid of the noise but created a new problem – when you switch on the Vreg I looked at the Vout and saw 5V coming out of the 3.3 Vreg for about 2s, then 3.3V(!). Disconnected the Electrolytic, and it goes direct to 3.3V (with the noise coming back). I’m running this with a Hope RF chip plugged at the end and it’s Abs Max is 3.6V so either 10uF was really throwing off the feedback, or the solution might simply be to replace Cout.