STM32 STDIO pins number are now configurable

[jeromecoutant]

Description

With that pull request, default configuration is not changed.

There are 2 goals for this PR:

• Help user when he wrongly defines an alternate UART pins from the same UART instance as the one configured for STDIO
  Now the failure becomes blocking, and an error message is printed.

• Help user to define his own STDIO pins (for a custom board for ex or if ST-Link is removed), only a json configuration update is needed.
  A good example could be the UBLOX board:

  "UBLOX_EVK_ODIN_W2": {
  "config": {
  "stdio_uart_tx": {
  "help": "Value: D8(default) or D1",
  "value": "D8"
  },
  "stdio_uart_rx": {
  "help": "Value: D2(default) or D0",
  "value": "D2"
  }
  }

@andreaslarssonublox

Status

READY

[0xc0170]

If the old name is used, this breaks it. Shouldn't this be done backward compatible, and then cleaned up for the minor where it can be documented how to update the application?

This change could be as is, but the target code should handle both cases (thus target override in the app would work if it overrides usb_tx there)

[jeromecoutant]

Yes, I agree.
I will update code.

[jeromecoutant]

@0xc0170
Change done, see last commit 9c6e7c0

[0xc0170]

bad rebase ? these pins should be redefined here?

[jeromecoutant]

No, as there is no "user choice" for this target, the default configuration in the PinName.h file should be sufficient ?
No need to overload the json file.

[0xc0170]

I was wondering how this is different than from Odin target (line 1818 changes it to a new name) but here you remove it here, thus I asked.

Not clear the line 1831 removal of stdio_uart for odin also?

[jeromecoutant]

Yes, STDIO_UART is not used any more in serial_api.c file

[jeromecoutant]

Here is a wiki page to help user : https://os.mbed.com/teams/ST/wiki/STDIO

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 855
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/5795/

Triggering tests

/morph test
/morph uvisor-test
/morph export-build

[mbed-ci]

Exporter Build : SUCCESS

Build number : 526
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/5795/

[mbed-ci]

Test : FAILURE

Build number : 699
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/5795/699

[0xc0170]

@jeromecoutant Please can you review the failures

[0xc0170]

/morph test

[mbed-ci]

Test : SUCCESS

Build number : 713
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/5795/713

[atoy40]

@jeromecoutant I'm testing 5.7.4 and this feature with a L073RZ board and there is an issue.
As stdio_uart_tx/rx are not defined into the target file, you cannot use in your config :

"target_overrides": {
        "NUCLEO_L073RZ": {
             "target.stdio_uart_tx": "tx pin name",
             "target.stdio_uart_rx": "rx pin name",
        }
    }

It is ignored and does not generate macro into mbed_config.h.
As you've used MBED_CONF_TARGET_STDIO_UART_* as macro name in PinNames.h, you cannot write :

"config": {
          "stdio_uart_tx": {
              "value": "tx pin name"
          },
          "stdio_uart_rx": {
              "value": "rx pin name"
          }
      }

because config variables are prefixed with MBED_CONF_APP_

The workarround is to force macro name :

"config": {
        "stdio_uart_tx": {
            "value": "tx pin name",
            "macro_name": "MBED_CONF_TARGET_STDIO_UART_TX"
        },
        "stdio_uart_rx": {
            "value": "rx pin name",
            "macro_name": "MBED_CONF_TARGET_STDIO_UART_RX"
        }
    },

but is it expected ? I imagine the first code sample is the one to use ?

thanks
Anthony.

[jeromecoutant]

Hi

As indicated in https://os.mbed.com/teams/ST/wiki/STDIO

Here is how I checked it with a mbed_app.json :

{
"config": {
"stdio_uart_tx": {
"value": "PA_2"
},
"stdio_uart_rx": {
"value": "PA_3"
}
}
}

It is true it is not specific to NUCLEO_L073RZ in this case...

[atoy40]

@jeromecoutant as I said, if you use that, your two macros will be named : MBED_CONF_APP_XXX and not MBED_CONF_TARGET_XXX as it is expected in the code (PinNames.h).

[jeromecoutant]

Mmmm

Maybe I should add an empty config in the FAMILY_STM32 in targets.json ?

    "config": {
        "lse_available": { ... }
        "stdio_uart_tx": {
            "help": "xxx"
        }
        "stdio_uart_rx": {
            "help": "xxx"
        }
    },

Let's try

[atoy40]

Yes this is what you have to do to allow target_overrides. And why do not put default board value in the target file ? instead of putting it into PinNames.h ?

[jeromecoutant]

why do not put default board value in the target file ?

Because I don't want to make this huge rework... :-)
I am going to send a PR with the above proposition