Lpc2000

Hi,

first of all, I would like to thank Rick (redspy) for being persistent
enough to trigger more investigations on power usage on the LPC2000
devices. 

These measurements have been conducted with Vdd=1.8V on LPC2129
devices but are fairly representative for all the 64-pin devices.

A device coming from Reset has all peripherals enabled and running at
max speed 60 MHz with MAM and PLL enabled uses between 35 mA and 40 mA
when executing the Blinky program.

Going from here there are options to decrease or increase the power.
At reset all peripherals are enabled as mentioned above BUT there is a
divider for the peripheral clock implemented that slows down the clock
to the peripherals. It is called VPB divider and serves two purposes:

1. Enabling Philips to use slow peripherals if needed
2. To reduce power consumption if peripherals do not need to run full
speed. 

The divider is set to /4 at reset and reduces the power consumption of
the total peripheral block. If all peripherals remain active AND the
divider is set to /1, the power consumption increases by approx. 15mA
into a range between 50-55 mA. 
The other option to change power related to peripherals is by using
the PCONP register. Setting the PCONP register to all "0" reduces
power but leaves you stranded without peripherals. Please check the
User Manual for details which bits enable which peripheral. As a rule
for power saving, it is good practice to set the whole register to "0"
and enable the peripherals you want to use.
Depending on the setting of the VPB divider power usage of the
peripheral block with all peripherals active and max speed is between
15-20 mA but with VPB divider set to /4, it is between 3-5 mA.

Summary:
You can run the CPU at full speed, have all peripherals active and
still use around 40mA when the clock to the peripherals is divided by
a factor of 4.
The upper end of the power consumption we saw in the range of 55mA
with everything running at max. frequency and all peripherals active,
no divider. 

Hope this answers many questions that have come up in the past. 

How does this relate to the LPC2104/5/6.
All numbers are a lower by a few milliamps but in general the behavior
is very similar. 

Best regards, Robert