Repository : ssh://git@open-mesh.org/doc
On branches: backup-redmine/2019-11-07,master
commit 65ffcac52f4393fe7d44f9388bd0389a35326ba1 Author: Sven Eckelmann sven@narfation.org Date: Sun Oct 27 18:47:39 2019 +0000
doc: open-mesh/Kernel_debugging_with_kgdb
65ffcac52f4393fe7d44f9388bd0389a35326ba1 open-mesh/Kernel_debugging_with_kgdb.textile | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/open-mesh/Kernel_debugging_with_kgdb.textile b/open-mesh/Kernel_debugging_with_kgdb.textile index 7194ce6..73264bb 100644 --- a/open-mesh/Kernel_debugging_with_kgdb.textile +++ b/open-mesh/Kernel_debugging_with_kgdb.textile @@ -317,14 +317,14 @@ index a7c6a79..c18f978 100644
h2. Working with external Watchdog over GPIO
-There are various boards on ar71xx which use external watchdogs chips via GPIO. They have to be triggered regularly (every minute or more) or otherwise the board will just suddenly reboot. This will of course not work when Linux is no longer in control and kgdb/gdb is the only way to interact with the system. +There are various boards on ar71xx which use external watchdogs chips via GPIO. They have to be triggered regularly (every minute or even more often) or otherwise the board will just suddenly reboot. This will of course not work when Linux is no longer in control and kgdb/gdb is the only way to interact with the system.
But luckily, we can just write manually to the ar71xx registers (every n seconds). We have two possible ways:
* write to the clear/set registers ** set bit n in register GPIO_SET (0x1804000C) to set output value to 1 for GPIO n ** set bit n in register GPIO_CLEAR (0x18040010) to set output value to 0 for GPIO n -* overwrite complete GPIO_OUT (0x18040008) register (which might modify more GPIO bits then required) +* overwrite the complete GPIO_OUT (0x18040008) register (which might modify more GPIO bits then required)
We will only demonstrate this here for GPIO 12 with GPIO_SET/GPIO_CLEAR.