Lpc2000

In LPC21xx, GPIO SET/CLR registers are designed so you don't need to 
read them in order to set/clear the corresponding GPIO bits:

GPIO0_IOSET |= (1<<15); <---- Unnecesary read
GPIO0_IOSET = (1<<15); <---- Changes (sets) only bit 15
GPIO0_IOSET = (1<<15)|(1<<4); <---- Changes (sets) bits 15 and 4
GPIO0_IOCLR = (1<<15); <---- Changes (clears) only bit 15
GPIO0_IOCLR = (1<<15)|(1<<4); <---- Changes (clears) bits 15 and 4

This feature allows you to modify individual bits without read-modify-
write operations which normally require disabling interrupts in order 
to ensure a consistent read.

Guille

--- In lpc2000@yahoogroups.com, Boris Králik <kralikbo@...> wrote:
>
> OH, sorry.
> Port operations:
> GPIO0_IOSET |= (1 << 15);//Write
> 15_bit_of_port_0 = (PCB_PINSEL0 >> 15) & 0x1); //Read
> --- Boris Králik <kralikbo@...> wrote:
> 
> > var |= (1 << 5); //set 5 bit of variable var to 1
> > (writing)
> > if (var & (1 << 5)) //test 5 bit of var (reading)
> > 
> > --- Mukund Deshmukh <betacomp_ngp@...>
> > wrote:
> > 
> > > Hi,
> > > A stupid question...
> > > I am used C51 and like bit addressing in 'C', but
> > in
> > > LPC its not possible.
> > > 
> > > 1. Is there any way I can read or write a port bit
> > > by simply writing /
> > > reading 1/0 .
> > > 
> > > Example for writing
> > > 
> > > Some_bit_P0_15=1
> > > 
> > > 
> > > or reading
> > > if (Some_bit_P0_15) {}
> > > 
> > > 
> > > 
> > > Best Regards,
> > > 
> > > Mukund Deshmukh.
> > > Beta Computronics Pvt Ltd,
> > > 10/1, IT Park, Parsodi,
> > > Nagpur-440022
> > > Cell - 9422113746
> > > 
> > > 
> > 
> > 
> > Regards / S pozdravom Boris Kralik
> > 
> > http://www.geocities.com/kralikbo/
> > -------------------------------------------------
> > 
> > 
> > 		
> >
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> 
> Regards / S pozdravom Boris Kralik
> 
> http://www.geocities.com/kralikbo/
> -------------------------------------------------
> 
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