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> Serial Console On Cacko Rom With Cl1000
post Jul 3 2006, 02:01 AM
Post #1

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Posts: 14
Joined: 9-May 06
Member No.: 9,821

Hi List,

Just thought I'd share my experience of setting up a sl-c1000 for development work.

I am doing kernel driver hacking, and I was losing the kernel panic and printk output, so I needed a serial console.

Unfortunatly this was not as easy as it seems!

To get this to work, you need to recompile the kernel with Console support on
serial device option, and you also need to hack printk.c to add the ttyS0 device in register_console(), as the kernel command line options seem to get ignored.

You should then be able to get serial output at 9600,8,n,1 with no flow control.
(Note I only updated the kernel, not the modules)

To actually get the serial output from the device, you need either a sharp serial
cable, which I believe work, or to make up your own cable. I made up my own.

To get the connector I bought a cheap usb sync and power cable for the 5500,5600,6000,C860

This connector is documented for the c700 on the sharp website, but does not appear to be exactly the same for the c1000. The uart pins, gnd and VCC
are the same though.

TXD - 3
RXD - 4
GND - 8
VCC - 11 (3.3V)

(You could make up a complete RS232 interface if you wanted, but this is not
needed for just simple input and output. You would want the pins:
RTS - 5
CTS - 6
DSR - 7
DTR - 14)

You then need a RS232 level shifter chip to change this to +-12V.

Also these signals are the opposite sense to most designs - at idle the lines are at 0v, not 3.3v.

So if you have a level shifter which has an inverter built in (as most do), you need to invert the signals to and from the zaurus.

Hope this helps someone! I can now read my whole panic, and copy and paste the
backtrace, so I'm happy!

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post Nov 23 2006, 09:35 AM
Post #2

Group: Members
Posts: 48
Joined: 21-November 05
Member No.: 8,576

Hi tjchick,

nice information. Thanks!
Maybe i will use the serial console some day.

I'm playin' around with the serial port on my C3100 at the moment and i'd like to give you some feedback.
First i had some trouble to get characters out of the port using minicom.
It is solved now. Nothing worthless to report anyway wink.gif .

Perhaps it is worth to notice that the VCC at pin 11 on the connector is always powered up, even when the device is in suspend mode.
Maybe there is another behaviour with other roms, but this is what i realized when i did some measurements at the port running cacko 1.23 on the device.

So take this into account if you connect something to the port (e.g. the sharp RS232 adaptor or homemade stuff).

At least were in the software section so i will stop bothering you with more hardware details.


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