Re: [discuss-gnuradio] blinking LEDs

[Eric Blossom]

On Fri, Aug 18, 2006 at 11:02:59PM -0700, Oussama Sekkat wrote:
> Hello,
> 
> When the USRP is plugged in, the LED to the right of the USB controller
> blinks at a fast rate of about 3 times per second. Once a USRP application
> starts, that rate slows down to about 1 time per second. What controls the
> blinking of the LEDs?

software ;)

> Is it the blink_leds.c function in the usrp/firmware/src/common folder?
> The only reason I am asking that is to determine wheather the LED is
> controlled by the PC or the FPGA.

The LEDs are controlled by the FX2.  When you first power the usrp up,
a very small program is loaded out of the 256 byte EEPROM.  That code
puts the AD9862's into a low-power state and runs a tight loop that
blinks the led about 3 times per second.  See
usrp/firmware/src/usrp2/eeprom_init.c

Once the "regular" firmware is loaded, the slow blinking is done in the
timer interrupt service routine, isr_tick.  
See usrp/firmware/src/usrp2/usrp_main.c

Neither the PC nor the FPGA have anything do to with the blinking,
though the host can control the non-blinking led.  Try

  $ usrper led1 on
  $ usrper led1 off


blink_leds.c was a very early piece of test code.  It probably still
works, but I haven't tried it in years.

Eric