Programming interface for custom board (what is SWO signal?)

[awahba]

I am using a nucleo board to develop some FW (NUCLEO-L073RZ, with STM32L073RZTx), but I wish to use the device (STM32L011G4) in the final product and use the nucleo board to program.

I am not sure which pin on the SWO signal to.

Thanks,

Ashraf

[Tesla DeLorean]

SWO would typically be PB3, but is not supported on Cortex-M0(+) designs, which have a very basic SWD debug connection.

[waclawek.jan]

> I am not sure which pin on the SWO signal to.

There is no SWO on 'L0xx at all (it's an auxiliary debug pin, to output debug information from application, like using printf()).

The Nucleo64 datasheet is intended for the whole Nucleo range, i.e. also for those STM32s which do have SWO.

JW

[awahba]

Thank you for your help. I will only hook up SWDIO, SWCLK and RESET then.

Thanks,

Ashraf

[Tesla DeLorean]

You'll also need a GND pin, and VDD if you plan on using a standalone ST-LINK/V2

Using the NUCLEO's ST-LINK is a bit crude for production work, consider using more standardized headers if possible (space permitting, etc)

For new designs, consider the 10-pin ARM SWD connector.

Using the STM32L011 here for it's small size, but the 16KB FLASH is pretty tight for things that came from a L073

[Tesla DeLorean]

[awahba]

Hi Clive,

Thanks. I understand, GND and VDD are included. I also agree the Nucleo's STLINK is not ideal.

I just received a STLINK dongle, since I am tight on space, I designed a landing pattern for some pogo pins (cable from Tag-connect).

I soldered an STM32L0 on a breakout board. I am biassing/decoupling all VDD/GND. I pulled up reset, down boot0. I plan on only using the internal clocks.

I don't know why, but I can only connect when using the stlink utility, and the mode is "connect under reset".

Using the utility, I can program, erase. But using ST IDE, I cannot run the debugger.

The first time I try running I get the following message:

Waiting for debugger connection...

Debugger connected

     -------------------------------------------------------------------

                      STM32CubeProgrammer v2.4.0                 

     -------------------------------------------------------------------

ST-LINK SN : 003600453038510334333935

ST-LINK FW : V3J6M2B4S1

Voltage    : 3.24V

Error: ST-LINK error (DEV_CONNECT_ERR)

Encountered Error when opening C:\ST\STM32CubeIDE_1.3.0\STM32CubeIDE\plugins\com.st.stm32cube.ide.mcu.externaltools.cubeprogrammer.win32_1.3.0.202002181050\tools\bin\STM32_Programmer_CLI.exe

Error in STM32CubeProgrammer

Debugger connection lost.

Shutting down...

----

subsequent trials give me the following error:

Target no device found

Error in initializing ST-LINK device.

Reason: No device found on target.

------

only a power cycle (target and dongle) brings me back to the first error mode.

Thanks,

Ashraf