[En-Nut-Discussion] Blinking LED on Ethernut 3

[Marti Raudsepp]

Ste wrote:
> I would know which are the modifications to bring to the example "Blinking
> LED"  available on the Ethernut web page in the section Nut/OS LED TUTORIAL
> (and here attached) so that runs also on Ethernut 3.

I don't know which pins or controllers the LEDs are attached to on the 
Ethernet 3 board, but this is how I can blink LEDs on my AT91 
development board.

I myself am using the header included with the AT91 development kit. 
This defines a huge number of register addresses. You can get it from 
http://www.keil.com/dd/docs/arm/atmel/sam7x/at91sam7x256.h

   #include <at91sam7x256.h>

Alternatively you may use the definitions from <arch/arm/at91_pio.h> -- 
which have to be redefined to volatile pointers to actually use them in 
C code:

   #include <arch/arm/at91_pio.h>
   typedef volatile unsigned int AT91_REG;
   #define AT91C_PIOB_PER  ((AT91_REG*)PIOB_PER)
   #define AT91C_PIOB_OER  ((AT91_REG*)PIOB_OER)
   #define AT91C_PIOB_SODR ((AT91_REG*)PIOB_SODR)
   #define AT91C_PIOB_CODR ((AT91_REG*)PIOB_CODR)

Four LEDs on my development board are bound to 19th...22nd pins of the 
parallel I/O controller B; the pin bits are defined as follows:

   #define LED1            (1<<19)	// PB19
   #define LED2            (1<<20)	// PB20
   #define LED3            (1<<21)	// PB21
   #define LED4            (1<<22)	// PB22
   #define LED_MASK (LED1|LED2|LED3|LED4)

The parallel controller (and most others) are operated through writing 
respective bit masks to certain register addresses.

Initialization of LED pins:
   // Enable specified pins on Parallel I/O controller B (PIOB)
   // (PER = PIO Enable Register)
   *AT91_PIOB_PER = LED_MASK;
   // Enable output on specified pins (OER = Output Enable Register)
   *AT91_PIOB_OER = LED_MASK;
   // Set (turn off) all LEDs (SODR = Set Output Data Register)
   *AT91_PIOB_SODR = LED_MASK;

Controlling the LEDs:
   // Turn on LEDs 1 and 3 (CODR = Clear Output Data Register)
   *AT91_PIOB_CODR = LED1|LED3;
   // Turn off LEDs 1 and 2 (we've seen SODR before)
   *AT91_PIOB_SODR = LED1|LED2;

This should be fairly straightforward to adapt to the blinking LED 
example if you can figure out the PIO pins on your board.


Regards,
Marti Raudsepp
Voicecom OÜ