[Lenny400] LetuxOS on SD card for MIPS JZ4780 CI20

H. Nikolaus Schaller hns at goldelico.com
Sun Apr 14 09:32:19 CEST 2019


> Am 13.04.2019 um 22:14 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
> 
> Hm. Yes, this one looks strange:
> 
> 	http://download.goldelico.com/letux-u-boot/CI20/2019-04-13/src/CONFIG
> 
> Maybe my script that copies it to the server is broken... Or the old U-Boot code
> does not store a copy in .config and the script copies the last one found in
> the source tree? Yes, the file ".config" is from Feb 2019 so it was not created
> by the make process.

Yes. I have fixed it. It is newer Kconfig based U-Boot which writes .config.
Older U-Boot does not touch it if it exists from a different make run.

> 
>> One thing which I did encounter was some confusion about which UART was being 
>> used. Ultimately, I used UART0, but I do wonder if U-Boot might use another 
>> UART early on.
> 
> Yes, the eserial4 is indicative...
> 
> But I have not changed any line of the source code (well one about endianness
> if host gcc is used).
> 
> What could be is that I should connect to the other UART port... And U-Boot
> switches to eserial4 just after printing "Err:   eserial4". Therefore the
> first message I can see on eserial4 is "Net:   dm9000".
> 
> If we dig into the U-Boot source it should be possible to find these definitions.
> And change them to our needs (stable console port...).

I have now checked with https://www.elinux.org/CI20_Hardware#Dedicated_UART_header
and my FTDI is connected to the primary expansion header:

pin 6	black	GND
pin 8	white	UART0_TXD
pin 10	green	UART0_RXD
(nc)	red	USB +5V - BTW: it should be possible to connect to pin 2/4 and power the board through the FTDI USB...

So I have no UART4 connected and in use. Is this the white JST connector?

BR,
Nikolaus



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