BB-STM32WL and Platformio/Arduino and STM32LoRaWAN

[winfried]

For a project, I wanted a private LoRa Network with many of these.

I managed to develop it with the LoRa-STM32WL-DevKit using cmis-dap and also debug and also program it via Serial Device (ESP-Prog), using PA10, PA9 pins, boot button and reset. (note: a newer stm32flash app was needed)

In both cases the serial output always is monitored on LPUART1 TX = PA2, RX = PA3.
(Any hints how I can route to PA9/PA10 are welcome).

see https://git.iem.at/ritsch/pfb-bees.git -> experiments/03-basic
(mostly from the examples form the STM32LoRaWAN library.)

see platformio.ini there.


The main issue: I can send a package but don't receive ones and stuck.

Since I am not an LoRa expert maybe one LoRa-wizard can help me here.
Maybe I miss an additional initialization needed and how can I test/measure if something is really transmitted ?

mfG
 Winfried

[LubOlimex]

It might be better to directly contact the author of the project.

[winfried]

Thanks for answering and sorry for the misunderstanding, I am the author of pfb-bees and use STM32LoRaWAN from author STMicroelectronics.

Since LoRa arduino Lib does not support the STM32WL5xx, I choose the one from STMicroelectronics, which supports it. Any other suggestion is welcome.

Maybe with this community we can get a working example, for this educational project, here the questions:

Not being a LoRaWan expert:

Is it possible to make a local Network between all devices without a LoRaWan gateway ?

Are additional settings are needed for the Olimex Board BB-STM32WL with the board configuration `olimex_wle5.json` recommended by Olimex for platformio ?

[LubOlimex]

Oh.

About getting the serial over PA9/PA10 instead of PA2/PA3 it should be purely software effort to also use them as output. In PlatformIO it should be as simple as switching from Serial to Serial1 I guess. Looking into your platformio.ini first make sure to comment out line 30 (it forces the usage of the CDC pins):

-DUSBD_USE_CDC

and uncomment this line 34:

;-DSERIAL_UART_INSTANCE=1

Maybe do some minimal test:

Code Select Expand

void setup()
{
    Serial1.begin(115200);
}

void loop()
{
    Serial1.println("USART1 on PA9/PA10 working");
    delay(1000);
}
if that doesn't work, maybe Serial1 is not defined at all, add it and force it:

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HardwareSerial SerialPort(PA10, PA9); // RX, TX

void setup()
{
    SerialPort.begin(115200);
}

void loop()
{
    SerialPort.println("Forced USART1 mapping");
    delay(1000);
}
It should be possible to connect devices peer-to-peer but it won't be LoRaWan, just LoRa peer-to-peer... After manufacturing we test these devices in a similar way - we connect two devices that send some PING-PONG data between each other.

The json was provided by a customer, who struggled to find PlatformIO config, he also wrote "Bear in mind that I tested it only with the arduino framework (see frameworks section, not cmsis nor stm32cube)".

[winfried]

Thank you for the hints,

ad serial monitor for debugging:

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; -DSERIAL_UART_INSTANCE=1
This was used to get get the Serial output to cmis-dap using Devkit, since it registers also a /dev/ttyACM0 and didn't work, but maybe it switches to PA9 and PA10.

I want to avoid the approach in Code, since I want the same source code for "cmis-dap" and "serial programming", but it is a solution if others fails.

Also for "STM32flash" there are options to handle boot and reset, with "dtr" and "dtc" pins with your ESP-PROG, (so I can make a dev connector on my board):

Code Select Expand

  ...
 -i GPIO_string  GPIO sequence to enter/exit bootloader mode
            GPIO_string=[entry_seq][:[exit_seq]]
            sequence=[-]n[,sequence]
 -R      Reset device at exit.
 ...

I will try this and report back here on this post.

[winfried]

ad LoRa versus LoRaWAN

Yes you are right, thanks.

I misread the help at the "modem.joinABP(...)", where it states is does not need for data exchange the connection with the gateway, but it seems it needs a gateway for join process, so it does not configure the device same channels etc...

I hoped I can use the middleware interface of STM32LoRaWan lib from STM for P2P, but this is not documented enough without a ton of read and the AI pointed me in the wrong direction confusing LoRa and LoRaWan libs ;-).

But I found the RadioLib which supports STM32WLx. I will try to make P2P example working and post it here.

[winfried]

FYI:

ad serial monitor for debugging:

Now got a working setup for a LoRa_STM32WL_DevKit using USB for powering, programming and monitor and parallel a BB-STM32WL over serial port on PA_9 and PA_10,
the

Code Select Expand

-DSERIAL_UART_INSTANCE=1 did not help.

First Since Serial Monitor of "cmsis-dap" programmer on board is connected on PB_6 and PB_7 to the programmer on the devkit I have to set the pins.

For the Serial connection  I had to set the Pins to PA_9 and PA_10.

Hints:
There is an issue if the 5V of the USB is weak like below 4.95V, programming fails.
and the new naming of the pins need are PA_9 not PA9, also the STM32flash programm of
actual platformio was too old.

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; PlatformIO Project Configuration File for LoRa P2P (Peer-to-Peer) Test
; OLIMEX LoRa-STM32WL-DevKit - Direct LoRa communication without LoRaWAN
[platformio]
description = "LoRa P2P Test - Direct device-to-device communication"

[env]
platform = ststm32
framework = arduino

lib_deps =
    jgromes/RadioLib @ ^7.3.0
board = olimex_wle5
build_flags =
    -DUSB_MANUFACTURER="Olimex"
    -DUSB_PRODUCT="BB-STM32WL"
    -DBLINK_PIN=PC_15

; LoRa-STM32WL-DevKit: with built-in USB-to-serial converter for monitoring
; using CMSIS-DAP for programming/Debug.
[env:LoRa_STM32WL_DevKit]
upload_protocol = cmsis-dap
monitor_speed = 115200
build_flags = ${env.build_flags}
              -D PIN_SERIAL_TX=PB_6
              -D PIN_SERIAL_RX=PB_7

[debug]
debug_tool = cmsis-dap
debug_init_break = tbreak setup
build_flags = ${env.build_flags}
              -D PIN_SERIAL_TX=PB_6
              -D PIN_SERIAL_RX=PB_7

; BB-STM32WL program and monitor
; Upload over serial using USART1
;    USART1_RX : PA10
;    USART1_TX : PA9
; set uC to boot mode with nboot=low on reset
[env:BB-STM32WL_serial]
build_flags = ${env.build_flags}
              -DNODE_ID=0x2
              -D PIN_SERIAL_RX=PA_10
              -D PIN_SERIAL_TX=PA_9

upload_protocol = serial
upload_port = /dev/ttyUSB0
upload_speed = 115200
monitor_port = /dev/ttyUSB0
monitor_speed = 115200

The So I can switch between the two devices for testing.

[winfried]

FYI,

But I found the RadioLib which supports STM32WLx. I will try to make P2P example working and post it here.

RadioLib is great,
so I got a working LoRa P2P example see
- https://git.iem.at/ritsch/pfb-bees.git -> experiments/05-p2p-radiolib

Thanks for help will be the firmware.

PS.: Is there a git repo for the BB-STM32WL KiCAD file, I can only find the PDF schematic and the KICAD for the LoRa-STM32WL-DevKit.

[LubOlimex]

Nice progress.

About the schematic - from what I can see it seems that BB-STM32WL is not an open-hardware design. For boards that are not OSHW we only share the PDF export of the schematic.

[winfried]

ok, I overlooked it, anyway thanks for the schematics.

BTW fyi:
I found you are using XTAL so, in radiolib we need to set TCXO_VOLTAGE to 0V, so it runs.

[winfried]

Trying to use the DCM and EN outputs from ESP-PROG for RESET and BOOT0 on BB-STM32WL board.

Also for "STM32flash" there are options to handle boot and reset, with "dtr" and "rts" pins with your ESP-PROG, (so I can make a dev connector on my board):

Code Select Expand

Code Select Expand

  ...
 -i GPIO_string  GPIO sequence to enter/exit bootloader mode
            GPIO_string=[entry_seq][:[exit_seq]]
            sequence=[-]n[,sequence]
 -R      Reset device at exit.
 ...

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upload_flags = -R -i '-rts,,-dtr,,,dtr&rts:,-dtr,,,dtr'
        ; GPIO sequence adding delay after port opening:
        ; - entry sequence: rts=low,200ms,dtr=low, 300ms delay, dtr&rts=high
        ; - exit sequence:dtr=low, 300ms delay, dtr=high

Following questions:

Assume connect EN to RESET and DCM to BOOT0 I cannot find a working sequence.
Do not understand what is the logic of DTR with RTS  to EN and DCOM signals on ESP-PROG.

What could be a sequence of DTR and RTS to: "DCM low" and "EN low, 100ms, high" for reset and make DCM high again ?

[LubOlimex]

Hmmm, you might need oscilloscope for this one. I think the problem comes from ESP-PROG logic that is made for ESP auto-boot and STM32 boot logic is possibly different. Maybe try with

Code Select Expand

-i '-rts,,-dtr,100,dtr:,-rts'

Code Select Expand

upload_flags = -R -i '-rts,,-dtr,100,dtr:,-rts'
I think to enter STM32 system bootloader:

BOOT0 = HIGH
RESET = LOW
wait ~100 ms
RESET = HIGH
BOOT0 can stay HIGH (or go LOW after reset)

To exit bootloader:

BOOT0 = LOW
RESET pulse again

If it does not work, the signals may be inverted on your ESP-PROG. In that case, swap rts with -rts and dtr with -dtr. If possible, verify with a multimeter or oscilloscope that:

EN actually goes LOW during reset and BOOT0 actually goes HIGH during boot. That will show whether inversion is the issue.

[winfried]

Workin manual: the sequence is with buttons to GND:

BOOT0 -> low  (button closed)
RESET -> low  (button closed)
RESET -> high (button released)
BOOT0 -> high (button released)

--
To understand the Transistor Logic in ESP-PROG it did, thanks to KiCAD, a fast simulation on /RTS and /DTR to DCOM and EN see picture below:


It seems, there is no combination of both signals being low at the same time, so it does not work, or am I wrong ?

[LubOlimex]

I think you are correct. It seems the ESP-PROG design was made only for ESP boot sequence. I will add it as a note on the product page. Maybe jut use regular general-purpose USB-serial cable. Like:

https://www.olimex.com/Products/USB-Modules/Interfaces/USB-SERIAL-L/

USB-SERIAL-L does not internally couple RTS and CTS. But you must wire it properly and probably put like 1k resistor between RTS and boards RESET and between CTS and BOOT0.