Lpc2000

Hi,
why not using the LPC214x, that has all the benefits of the LPC2138
plus USB on-chip. Programming through USB directly though is not
supported yet, may be Philips should come up with a solution there.
In regards to your 3.3V first followed by 1.8V is not a problem.
Usually these regulators follow the rising edge of the 3.3V fairly
quickly and by the time you reach 3.3V the 1.8V are there as well.
Bob

--- In lpc2000@yahoogroups.com, Peter Jakacki <peterjak@t...> wrote:
>
> Ez,
> 
> First off can I recommend that you consider using the 2138 in place of 
> the 2106. I started off with the 2106 and the only reason I would
use it 
> now is because it has more RAM and possibly because it's a smaller 
> package. The 2138 has it's own 1.8V regulator and as you already have a 
> 3.3V supply it means you can do without the size and cost of additional 
> regulators.
> 
> To answer your question though, yes, you can connect the 1.8V regulator 
> in series with the 3.3V without problems.
> 
> I am not sure about the FTDI question however, though there shouldn't 
> really be a problem as these types of chips are designed to be operated 
> this way. Personally, I find the CP2102 devices far easier to use as 
> they truly are a SCFF* single-chip USB-UART bridge.
> 
> *Small, Cheap, Fast, and Flawless (as far as I can tell).
> 
> *Peter*
> 
> 
> Ezequiel L. Aceto wrote:
> > Hello
> >
> > I'm designing a little device with the LPC2106. I have worked with
> > this MCU but never in the situation that I wanted to work now.
> > I need to power the LPC2106 only with 3.3V, and also attach a FTDI232
> > USB (to program the LPC, and also as a virtual Comm for the PC).
> >
> > One of the problems comes with the power supply for the LPC, can I
> > give 3.3V directly to the MCU, and connect a regulator to the 3.3V
> > line to generate 1.8V?  I always connected 3.3V and 1.8V "in parallel"
> > as a 5V supply feed them, but now I only have 3.3V and don't know if
> > there is a problem to give first (for a few mSec) 3.3V and then 1.8V.
> >
> > And last but not least, I need to power the FTDI with 3.3V, which is
> > not a problem, but I will only have 5V when connected to the USB, then
> > I will only have 3.3V. So I will connect and power VCCIO with 3.3V but
> > the other voltage sources will "float" when the device is not
> > connected. Might this cause any problem?
>