====== About ====== From factory Carambola is shipped with ttyS0 disabled. Or to be more precise it is in GPIO mode. Which is sometimes not what we want. It is very easy to change this. ====== MMIO ====== In order to change internal Carambola registers you need small tool called ''io''. You can install it when building the carambola distribution or later by running opkg install io If for some reason you get error installing io (for a while it was not on package repository, now it is fixed), download it compiled. cd /usr/bin wget http://www.8devices.com/files/mmio chmod 777 ./mmio ====== Registers ====== Registers of interest: ''(System Control) 0x1000.0000 + (GPIO Purpose Select offset) 0x60'' ====== Read to test ====== Check what you have. 0x1D means you need to change it. root@OpenWrt:/tmp# ./io 0x10000060 10000060: 1f ====== Change ttyS0 mode ====== One single command. ./io 0x10000060 0x01 ====== inittab ====== Edit your /etc/inittab file to look like this: root@OpenWrt:/# cat /etc/inittab ::sysinit:/etc/init.d/rcS S boot ::shutdown:/etc/init.d/rcS K shutdown #ttyS0::askfirst:/bin/ash --login #<------------- comment this line to disable console on ttyS0 ttyS1::askfirst:/bin/ash --login ====== Future work ====== If you wish (and probably it is so) you need to run this command every time you start your Carambola. This can be done by altering ''/etc/rc.local'' file to something like: io 0x10000060 0x01 exit 0 *Note: This is quick and dirty way to enable ttyS0.