On 04/16/2013 08:58 PM, Scott Sullivan wrote:
On 04/16/2013 06:58 PM, Robert Moskowitz wrote:
>
> On 04/16/2013 05:40 PM, Scott Sullivan wrote:
>> On 04/16/2013 05:24 PM, Robert Moskowitz wrote: I am looking at the
>> instructions at
>>>
>>>
http://fedoraproject.org/wiki/Architectures/ARM/F18/GuruPlug
>>>
>>> And am I suppose to be using a serial port during this first boot?
>>> I do
>>> have a USB serial device, but I would need that on my linux
>>> notebook for
>>> a serial port. Oh, wait, I have an old XP notebook with a serial
>>> port... If this USB serial device works, do I use a 'regular'
serial
>>> cable (whatever that is these days) and what port settings do I use?
>>
>> /!\ Do Not Use a normal serial adapter/port! The logic levels will be
>> at 12volts and will fry your pogoplugs UART.
>>
>> The pogoplus expects 3.3V logic level.
>> I personally use one these
https://www.sparkfun.com/products/9873
>
> Where does this get plugged into? Do I break open the case? All I see
> on the outside is power, LAN, and 4 USB ports.
Internal Header, this is a good photo.
http://www.hack247.co.uk/hack247/wp-content/uploads/serialport.jpg
I've got a little adapter cable I built to go from the JST connector
for the serial to the correct pins on that USB to 3.3v Serial adapter.
OK. I don't get this. I am not a hardware hacker. Or rather I stopped
that 20 years ago or so.
You'll find the vast majority of arm devices do not have proper 12v
RS232. Instead they have a UART which is serial with only the TX, RX
and GND lines. The usually operate at the core logic voltage of the
SoC and if you apply the wrong voltage you'll fry the UART.
Yet there are the USB to serial devices that work off the 5v USB just
fine. Or fine enough to connect to a serial port on a firewall, switch
or router.
If I plug mine in to the USB, will it be recognized during the boot? Or
does it need Linux running, so it can't be used as a boot monitor?
Most of my devices have had 3.3v serial UARTs including the openWRT
capable routers I experiment with, so I invested in that adapter. It's
served me rather well as I can easily us jumper wires for custom
adapter cables for each board.
So to do this, I am going to have to invest in some hardware. :(