Re: SIMtrace v0.8

Hi Kevin, On Tue, May 10, 2011 at 09:57:29AM +0200, Kevin Redon wrote: fine with me. I honestly don't care about the number of batteries... and the PCB will not be smaller than 4x AAA/AA anyway. that should work, but you should use something like a 1N4001 as the diode, to cope with more current. However, I would want to have that tested on a breadboard before sending the gerber off for PCB manufacturing, just to make sure the power supply side is working. We still have a problem if somebody decides USB _and_ the battery power supply :/ In fact, now that I'm thinking off it, we should use one of those jacks which disconnnect one contact when plugging in the power supply. This way we can actually interrupt the USB 5V once a power supply plug has been plugged in. This should be done independent of the decision on the voltage regulator. looks not that trivil to me, as you don't only need the FDN304 but also the LM358 op-amp and external circuitry. Probably a bit overkill. So I think we should route the 5V USB via the power plug, and simply use a low-drop-out 3.3V regulator, like in the current schematics. This way the LDO input will be USB 5V _until_ somebody plugs in an external power supply or battery pack, which will have to provide at least 3.4V for stable operation. Regards, Harald -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)