Lpc2000

I finally got to the point of shutting down the LPC2138 on the Keil 
development board. Battery life is critical to my application, 
therefore I need to verify the sleep specification. At room 
temperature, with all I/O configured as input except for JTAG, I am 
measuring 350mA just on the VDD pins! Far from 10uA. All peripheral 
clocks are disabled except the RTC which is configured to use the 
32kHz. 

FYI:
Vbat: ~31uA while processor is on, ~18uA during powerdown. (Just for 
the RTC?!?!)

When it comes to sleep current issues, the first thing vendors 
usually question is the I/O state. The following are the relevant 
register values:

PINSEL0: 0x0
PINSEL1: 0x0
PINSEL2: 0x4

IODIR0: 0x0
IODIR1: 0x0

IOPIN0: 0x7EFFF7F8
IOPIN1: 0x03FF0000

I'm puzzled about the I/O:
1.) The IOPIN register does not necessarily reflect the state of the 
I/O line. For example, P0.4 is not connected on the Keil board. 
Since this pin is configured as an input, I would suspect the 
voltage on the pin to reflect the internal pullup, but it measures 
0V. Even more puzzling, IOPIN0 states this input is high. Go figure.

2.) Another concern: P0.31 is not connected, but configured as an 
input. If I measure the pin voltage it is 2.3 instead of 3.3V. This 
is also true for P1.16-23 and P1.24-25. Could I be leaking current 
through the pullup resistor?

-Tim



--- In lpc2000@yahoogroups.com, "philips_apps" <philips_apps@y...> 
wrote:
> 
> Hello, 
> 
> You are right that the value for typical changed and unfortunately
> both values did not hit the mark that we saw on the bench. While 
30 mA
> was too low, 60 is too high. 
> 
> Acceptance criteria for test is 70 mAs max, this includes temp
> variation and chip-to-chip variations. So consider 70 mAs the max
> value. Test is done with peripherals enabled, that means, the 
clock is
> provided to most of the flipflops, which causes the current
> consumption. Running the peripherals or just having them enabled 
does
> not show a difference in power consumption of more than 5 mAs. In
> fact, running them caused the current to drop a couple mAs. The
> highest current we measured in characterization based on a core
> voltage of 1.8V was less than 60 mAs, only if the core voltage
> increases to the max. of 1.95V we saw single devices exceeding 60 
mAs. 
> 
> When we really disabled the peripherals using the PCONP register 
and
> leaving the VPB-divider at the initial divide by 4, we saw current
> consumption around 35 mAs running at 60 MHz without peripherals. 
> 
> The major difference is disabling the peripherals and / or the VPD
> divider for the peripheral bus. With the divider you can save 
approx.
> 10 mAs and with disabling them all approx. 15 mAs based on 60 MHz
> operation.
> 
> There are so many conditions but in general, the active power is
> highly dependend on your core voltage, highly dependend on your
> VPD-DIV, highly dependend on the settings in PCONP, MAM-enabled, 
PLL
> enabled.
> Less dependency but still some differences for single peripherals
> running or not, operating temperature.
> 
> Idle power depends mostly on the frequency provided to the
> peripherals, so VPBDIV and PCONP. Disabling the PLL also makes a
> significant difference. Recommendation disable PLL and set VPBDIV 
to 4
> while disableing unused peripherals in PCONP. Measured value used
> above recommendations at 10 MHz and all peripherals disabled was 
2.3
> mAs, same conditions 20 MHz was 4.5 mAs. With PLL enabled and 
running
> the peripherals at max speed idel power can be around 20 mAs.
> 
> For power down current the most important factor is temperature! 
While
> most of our devices are around 10 uAs at room temp, they are >100 
uAs
> at 85C.
> 
> Let me apologize for the confusion. Will work hard to do better in 
the
> future!
> 
> btw. as a courtesy it would be nice to identify yourself by name. 
> 
> Robert
> 
> 
> --- In lpc2000@yahoogroups.com, "lp2000c" <lp2000c@e...> wrote:
> > 
> > The latest LPC2114 Data Sheet shows a Typical 1.8V current of 60 
mA 
> > (at 25 degrees, with no active peripherals).  This is double the 
> > value published in the previous "prleiminary" revision.
> > 
> > Philips Apss:
> > What is the Maximum current draw (including chip-to-chip 
variations, 
> > and temperature efffects?)
> > What is current draw with all peripherals active?