Hi Richard,
(First post for me) - working through the forum especially the pics of the teardown
http://blueprinted.co.uk/clarity/ there is a pinout consisting of 4 pads labelled CON1 . It would be a large leap to think that this might be of of the serial ports referred to in /proc
If you open the terminal and go to /proc/tty/ and then cat drivers you can see that:
ttySAC /dev/tty-uart 204 64-69 serial
more information can be found doing: cat /proc/driver/ttySAC which shows that there are 6 serial ports however only the first 2 seem to be properly setup:
0: uart:uart0 mmio 0xF0532000 irq 64 tx: 48 rx: 0 RTS CTS DTR DSR CD
1: uart:uart1 mmio 0xF0532100 irq 65 tx: 0 rx: 0 CTS DSR CD
The device files are also present in /dev
Looking here:
viewtopic.php?f=9&t=273&p=3109&hilit=serial#p3109 you can see that there are 6 serial ports on this SOC (which are all accounted for).
The other option is that CON1 is a USB port - as the USB OTG port is accounted for at the bottom of the machine this could be USB 1.1 Host
Both would be quite cool hacks to add to the scrollforum knowledge base.
My suggestion on how we could work out what is what is to open up a scroll tablet, first using a multimeter check out the voltages on the pins, if it was a usb port we would expect one pad to be 5v and the other ground, the other 2 pads being data- and data+. However I guess you could think that serial could be vcc, rx, tx, gnd as well.
The best way would be to connect up up those pads to a ttl serial port (well gnd and tx) and then transmit data over the serial port such as:
echo "test" >/dev/tcc-uart0
if it is a serial port you 'should' get data out the other side. In contrast attaching a usb device to CON1 and seeing if anything was detected might work - i think the serial port experiment is probably the simplest and easiest.
Now to summon the courage to crack open my scroll tablet.
James