What's the actual current consumption of LPC2100 ?

Started by microbit November 18, 2003
Hi Leon et al,

First of all, thanks Leon for starting this group - I think it's a great
idea.

I should be able to start writing SW very soon on LPC2100 (should read :
first fiddle with it :-),
But I've been trying to figure out for a little while now what the actual
current
consumption is of LPC's core at say 60 Mips.

The latest datasheet I D/L of Philips site seemed to indicate 30 mA.
Sure that can't be right ?
(Mind you - it took Philips to invent the very low power CoolRunner CPLD)

I'll be testing this very soon, but I'm "full of anticipation"

Best regards,
Kris



An Engineer's Guide to the LPC2100 Series

On Wed, Nov 19, 2003 at 01:46:18AM +1100, microbit wrote:

> The latest datasheet I D/L of Philips site seemed to indicate 30 mA.
> Sure that can't be right ?
> (Mind you - it took Philips to invent the very low power CoolRunner CPLD)

I think because of the low voltage (1.8 volts) this could be possible.
However, the flash is slower than the CPU (can work at 20 Mips). The LPC2100
does some prefetching, with linear code you get the full 60 Mips, but with
loops and jumps you are slower.

> I'll be testing this very soon, but I'm "full of anticipation"

I am interested of the power consumption in "RTC-mode" - running mostly in
idle mode, just counting the internal RTC. I guess that are still some mA;
so I would need a separate battery powered real time clock (a MSP430 ;-).
Anyone experiences yet? (I do not have any hardware yet to make some tests
myself).

Matthias




--- In , Matthias Weingart <lpc2100@p...> wrote:
> On Wed, Nov 19, 2003 at 01:46:18AM +1100, microbit wrote:
>
> > The latest datasheet I D/L of Philips site seemed to indicate 30 mA.
> > Sure that can't be right ?
> > (Mind you - it took Philips to invent the very low power
CoolRunner CPLD)
>
> I think because of the low voltage (1.8 volts) this could be possible.
> However, the flash is slower than the CPU (can work at 20 Mips). The
LPC2100
> does some prefetching, with linear code you get the full 60 Mips,
but with
> loops and jumps you are slower.
>
> > I'll be testing this very soon, but I'm "full of anticipation"
>
> I am interested of the power consumption in "RTC-mode" - running
mostly in
> idle mode, just counting the internal RTC. I guess that are still
some mA;
> so I would need a separate battery powered real time clock (a MSP430
;-).
> Anyone experiences yet? (I do not have any hardware yet to make some
tests
> myself).
>
> Matthias
Matthias,

you are absolutely correct that the LPC210x need to run in idle mode
in order to support the RTC. This prohibits battery backup over a
longer period of time.
What about using the other LPC from Philips. Even the smallest LPC900
devices have a real-time clock on-chip. I would recommend the LPC901
and an external 32 kHz crystal. In case you need some performance out
of this device as well, switch to the internal RC-oscillator which
will provide you with almost 4 "51-MIPS".

In regards to the first question, power consumption, we did some
initial measurements and found around 36 mA for the 1.8V power supply.
This is the core and all the logic but no I/O was driven. At approx.
65mW, the package "stays cool"

One more comment to the loops and jumps and flash speed. There are
several mechanisms implemented to speed up the flash and make it close
to 0 WS. A single loop will not make the LPC210x slower, a nested loop
will because the outer loop will be causing delays.

This device is definitely worth the money considering that 8- and
16-bit devices providing the same amount of on-chip memory are more
expensive.

I heard that there will be low cost evaluation boards from IAR and
Keil coming out soon, both running below $200. Both are suppossed to
have a code-size limited compiler no expiration.

Cheers, Bob