Lpc2000

Thanks Tom,

I was looking for something that would let me do:

if(LED1)
  LED2 = 1;

This would require associating LED1 and LED2 with a particular bit in
the appropriate IOPIN register.  Judging from your response, this is
not possible with GCC and ARM?

Thanks,

Gary

--- In lpc2000@yahoogroups.com, Tom Walsh <tom@o...> wrote:
>
> ee_gary wrote:
> 
> >Hi everybody,
> >
> >I'm wondering what is the best way to set and clear I/O bits without
> >keeping track of what port they are on.  For example, something like:
> >
> >#define myOutput1 IO2PIN.1
> >#define myOutput2 IO3PIN.28
> >
> >  
> >
> As per ANSI C, define a MACRO, For example:
> 
> ============= begin ===============
> 
> typedef struct
> {
>   REG32 in0;                            // P0 Pin Value Register
>   REG32 set0;                           // P0 Pin Output Set Register
>   REG32 dir0;                           // P0 Pin Direction Register
>   REG32 clr0;                           // P0 Pin Output Clear Register
>   EG32 in1;                            // P1 Pin Value Register
>   REG32 set1;                           // P1 Pin Output Set Register
>   REG32 dir1;                           // P1 Pin Direction Register
>   REG32 clr1;                           // P1 Pin Output Clear Register
>   REG32 in2;                            // P2 Pin Value Register
>   REG32 set2;                           // P2 Pin Output Set Register
>   REG32 dir2;                           // P2 Pin Direction Register
>   REG32 clr2;                           // P2 Pin Output Clear Register
>   REG32 in3;                            // P3 Pin Value Register
>   REG32 set3;                           // P3 Pin Output Set Register
>   REG32 dir3;                           // P3 Pin Direction Register
>   REG32 clr3;                           // P3 Pin Output Clear Register
> } gpioRegs_t;
> 
> #define GPIO1            ((gpioRegs_t *)0xE0028000)
> 
> #ifndef BIT
> #define BIT(n)              (1 << (n))
> #endif
> 
> #define LED_EVENT_BIT      BIT(20)     // P1.20 output - low for
EVENT LED.
> 
> #define IOPIN1           GPIO->in1       /* Pin Value Register */
> #define IOSET1           GPIO->set1      /* Pin Output Set Register */
> #define IODIR1           GPIO->dir1      /* Pin Direction Register */
> #define IOCLR1           GPIO->clr1      /* Pin Output Clear Register */
> 
> ============== THEN DO ====================
> 
> main () {
>     IOCLR1 = LED_EVENT_BIT;
>     IOSET1 = LED_EVENT_BIT;
> }
> 
> ============ OR ================
> 
> < the above defines>
> 
> static inline eventLedOff (void) { IOSET1 = LED_EVENT_BIT; }
> 
> static inline eventLedOn (void) { IOCLR1 = LED_EVENT_BIT; }
> 
> void main (void)
> {
>     eventLedOn ();
>     eventLedOff ();
> }
> 
> ============  snip =====================
> 
> 
> Making the function both static and inline will optimize (-O2 or -Os) 
> into inline assembly rather than a function call.
> 
> There are no "bitwise" functions in gcc such as set_bit(LED_EVENT_BIT) 
> or clear_bit(LED_EVENT_BIT), but you can write your own...
> 
> 
> Regards,
> 
> TomW
> 
> 
> -- 
> Tom Walsh - WN3L - Embedded Systems Consultant
> http://openhardware.net, http://cyberiansoftware.com
> "Windows? No thanks, I have work to do..."
> ----------------------------------------------------
>