Notes on the behavior of the SmartHub LEDs
---

 

Red/Green LEDs: the boot process
~~~

 

As early as possible in the boot process, the strap turns the red led
on to indicate that the SmartHub is successfully executing
instructions from flash.  This won't be visible to normal life forms,
because it is almost immediately turned off when the kernel loader
begins executing.  However, if for some reason the loader is not
started (e.g. because of an infinite loop or bad branch instruction in
the strap), the red led will stay lit indefinitely.

 

If the strap fails to find a valid kernel at the start or end of
SmartHub flash, it will signal the error by pulsing the red led as per
the description below.

 

As already noted, when the loader starts executing, the first thing it
does is turn the red led off.  At this point it also turns the green
led on to indicate that loader code is being executed from flash.  The
green led will then 'dip' (switch off briefly) up to 3 times to
indicate loader progress.  The number of dips indicates the following
boot-phase milestones:

 

    [1]  RAM initialization succeeded
    [2]  RAM-targeted loader launched successfully
    [3]  About to launch the executable Linux kernel image

 

The green led subsequently stays lit until the Omega is rebooted.

 

Startup error states are signaled by pulsing the red led a number of
times equal to the error code number, pausing, then repeating ad
infinitum.  For example, a generic kernel loader error (code 2) will
look something like (where '!' = red led pulse):

 

        ! !  (pause)  ! !  (pause)  ! !  (pause)  ! !  ....

 

The error code numbers are:

 

    [1]  Strap failed to find a valid kernel.
    [2]  Generic kernel loader error (view the serial log for more detail).
    [3]  Serial transmit failed.

 


Ethernet LEDs
~~~

 

The yellow led is controlled autonomously by the AX88796 ethernet
chip.  It is lit when the chip detects a network layer link, and it
toggles periodically to indicate network activity.

 

The green led is controlled by software running on the SmartHub.  The
code to control the green ethernet leds has not yet been written, so
they can be ignored for the moment.
Notes on the behavior of the SmartHub LEDs
---

 

Red/Green LEDs: the boot process
~~~

 

As early as possible in the boot process, the strap turns the red led
on to indicate that the SmartHub is successfully executing
instructions from flash.  This won't be visible to normal life forms,
because it is almost immediately turned off when the kernel loader
begins executing.  However, if for some reason the loader is not
started (e.g. because of an infinite loop or bad branch instruction in
the strap), the red led will stay lit indefinitely.

 

If the strap fails to find a valid kernel at the start or end of
SmartHub flash, it will signal the error by pulsing the red led as per
the description below.

 

As already noted, when the loader starts executing, the first thing it
does is turn the red led off.  At this point it also turns the green
led on to indicate that loader code is being executed from flash.  The
green led will then 'dip' (switch off briefly) up to 3 times to
indicate loader progress.  The number of dips indicates the following
boot-phase milestones:

 

    [1]  RAM initialization succeeded
    [2]  RAM-targeted loader launched successfully
    [3]  About to launch the executable Linux kernel image

 

The green led subsequently stays lit until the Omega is rebooted.

 

Startup error states are signaled by pulsing the red led a number of
times equal to the error code number, pausing, then repeating ad
infinitum.  For example, a generic kernel loader error (code 2) will
look something like (where '!' = red led pulse):

 

        ! !  (pause)  ! !  (pause)  ! !  (pause)  ! !  ....

 

The error code numbers are:

 

    [1]  Strap failed to find a valid kernel.
    [2]  Generic kernel loader error (view the serial log for more detail).
    [3]  Serial transmit failed.

 


Ethernet LEDs
~~~

 

The yellow led is controlled autonomously by the AX88796 ethernet
chip.  It is lit when the chip detects a network layer link, and it
toggles periodically to indicate network activity.

 

The green led is controlled by software running on the SmartHub.  The
code to control the green ethernet leds has not yet been written, so
they can be ignored for the moment.