topic Re: Using printf() via UART in a bare metal project in Layerscape

Using printf() via UART in a bare metal project

djz — Thu, 07 Dec 2017 14:05:19 GMT

I have LS1046RDB board.

I installed CodeWarrior, set up bareboard project example and I managed to run the program via GDB and using built-in CMSIS-DAP I run it from RAM.

By default, printf() uses GDB redirection to CodeWarrior console. I followed Targeting Manual and changed linked library from simrdimon.specs to uart.specs.
But I don't see any output in a serial terminal on my PC.

Should I invoke any UART configuration / init function? Targeting Manual says only about changing the library. Is there any documentation of this UART library? Any API description or whatever?

I tried invoking InitializeUART, but to no avail and it was guessing. How can one use UART in a bare metal project?

Re: Using printf() via UART in a bare metal project

Pavel — Tue, 12 Dec 2017 06:15:08 GMT

Check your UART terminal setting.

There are no problems if UART is used via MBED under CodeWarrior.

See attached snapshot.

Have a great day,
Pavel Chubakov

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Re: Using printf() via UART in a bare metal project

djz — Tue, 12 Dec 2017 08:48:36 GMT

Yes, I did like that. But it was not working.

I think the problem is that I use hard-coded RCW. And from the Reference Manual it seems that the both possible hard-coded RCWs disable UART pins and configure them as GPIO...

But I don't know how to override RCW via JTAG. I tried using Initialization Script and commands:

gdb.execute("monitor rcw data set RCW11 0x00038000")
gdb.execute("monitor rcw apply")

But it either doesn't take any effect or return an error: "monitor rcw apply" failed. [GTA: error writing register].

Re: Using printf() via UART in a bare metal project

mark_xingchangy — Mon, 30 Jul 2018 13:55:12 GMT

Hi Dariusz,

Does your board work with UART printf? If yes, how do you solve it? I have met the same issue on LS1043ARDB EVK board now. Thanks!

B.R.

Mark Yang

Re: Using printf() via UART in a bare metal project

mark_xingchangy — Tue, 14 Aug 2018 18:33:53 GMT

Update on LS1043ARDB:

It works after the 2 steps as mentioned above

1. Change project properties as C/C++ Build -> Settings -> Tool Settings -> Cross ARM C Linker -> Miscellaneous as showed by Clipboard02.jpg in Pavel's reply above.

2.Change Target Initialization File in CodeWarrior as the following

# Override RCW using a safe hard-coded RCW option

USE_SAFE_RCW = True

... ...

gdb.execute("monitor rcw data set RCW12 0x00038800")

gdb.execute("monitor rcw apply")

Thanks!

B.R.

Mark Yang