Lpc2000

Hallo,

  i have a problem with too big current to peripherals at power down.
On the board where almost all IO pins at LPC 2214 remain unconnected
can't still achive consumption which will be at the range described in
the AP10404 or the latest AP10421 (i know they are primarily aimed to
different type...but in general i hope it could be similar in my case).
  
  The biggest problem seems to be with setting PINSEL2. Only if it's
left in its default value the consumpion stay low. An attemp to switch
pins controled by PINSEL2 to IO leads to current grows. 

                                                         Thanks.

Hi bernau84,

You say that when you set PINSEL2 to GPIO the supply current increases.
Can you do some more tests?
With PINSEL2 to I/O, is the current higher with each pin
(a) input: IOxDIR bit y = 0
(b) output high: IOxDIR bit y = 1, IOxSET bit y = 1
(c) output low: IOxDIR bit y = 1, IOxCLR bit y = 1
I expect all the pins on port 2 to behave similarly (excluding
the effects of any external components you have on pins P2.y)

If a given pin has a pull-up resistor (either on your board
or inside the lpc2214) then you should have low current consumption
when the pin is an input and low when the pin is output high,
but high current consumption when the pin is output low.

Similarly if the pin has a pull-down resistor, then you should
have low current consumption when the pin is input, low current
consumption when the pin is output low. But you will have high
current consumption when the pin is output high.

The above are reasonably obvious.
But if there is no pull-up resistor and no pull-down resistor,
then there might be *HIGH* current consumption when the pin
is an input (but low current consumption when the pin is an
output). This "class A" current occurs when the input voltage is
somewhere between high and low, and both the n-channel and
p-channel input transistors are turned on.

You might still be able to achieve low current consumption
provided you make those pins which are otherwise floating
into GPIO *outputs*.

Hope this helps,
Danish
--- In lpc2000@yahoogroups.com, "bernau84" <bernau84@...> wrote:

>
> Hallo,
> 
>   i have a problem with too big current to peripherals at power down.
> On the board where almost all IO pins at LPC 2214 remain unconnected
> can't still achive consumption which will be at the range described in
> the AP10404 or the latest AP10421 (i know they are primarily aimed to
> different type...but in general i hope it could be similar in my case).
>   
>   The biggest problem seems to be with setting PINSEL2. Only if it's
> left in its default value the consumpion stay low. An attemp to switch
> pins controled by PINSEL2 to IO leads to current grows. 
> 
>                                                          Thanks.
>

Thanks.

  I did some additional test about this. I have found out that when i
switch pins P2.31:30 and P3.29:28 from default AIN4:7 to IO, because i
try to minimalize leakage current on each ADC (200uA) if it stay
configured as analog input (according to AP10404)
   
    PINSEL2 |= 0x00000030;
    PINSEL2 &= ~0x006000C0;

the current increase from acceptable 0.3mA to 1.6mA. I'm sure i have
left these pins unconnected. This result goes directly again my
assumptions.

 All pins on P1, P2, P3 are tied high for their internal pull-ups.
Port 0 has no pull-up so it is switch to low output. Big difference 
doesn't accure when i switch it to input state.

                          I'll appreciate any help.
       
   


--- In lpc2000@yahoogroups.com, "Danish Ali" <danish@...> wrote:
>
> Hi bernau84,
> 
> You say that when you set PINSEL2 to GPIO the supply current increases.
> Can you do some more tests?
> With PINSEL2 to I/O, is the current higher with each pin
> (a) input: IOxDIR bit y = 0
> (b) output high: IOxDIR bit y = 1, IOxSET bit y = 1
> (c) output low: IOxDIR bit y = 1, IOxCLR bit y = 1
> I expect all the pins on port 2 to behave similarly (excluding
> the effects of any external components you have on pins P2.y)
> 
> If a given pin has a pull-up resistor (either on your board
> or inside the lpc2214) then you should have low current consumption
> when the pin is an input and low when the pin is output high,
> but high current consumption when the pin is output low.
> 
> Similarly if the pin has a pull-down resistor, then you should
> have low current consumption when the pin is input, low current
> consumption when the pin is output low. But you will have high
> current consumption when the pin is output high.
> 
> The above are reasonably obvious.
> But if there is no pull-up resistor and no pull-down resistor,
> then there might be *HIGH* current consumption when the pin
> is an input (but low current consumption when the pin is an
> output). This "class A" current occurs when the input voltage is
> somewhere between high and low, and both the n-channel and
> p-channel input transistors are turned on.
> 
> You might still be able to achieve low current consumption
> provided you make those pins which are otherwise floating
> into GPIO *outputs*.
> 
> Hope this helps,
> Danish
> --- In lpc2000@yahoogroups.com, "bernau84" <bernau84@> wrote:
> >
> > Hallo,
> > 
> >   i have a problem with too big current to peripherals at power down.
> > On the board where almost all IO pins at LPC 2214 remain unconnected
> > can't still achive consumption which will be at the range described in
> > the AP10404 or the latest AP10421 (i know they are primarily aimed to
> > different type...but in general i hope it could be similar in my
case).

> >   
> >   The biggest problem seems to be with setting PINSEL2. Only if it's
> > left in its default value the consumpion stay low. An attemp to switch
> > pins controled by PINSEL2 to IO leads to current grows. 
> > 
> >                                                          Thanks.
> >
>