Power LoRa disco board external

[Jeroen deBuffel]

Posted on July 05, 2017 at 14:32

Have been playing with the B-L072Z-LRWAN1 and it all works fine. Now we would like to hook up directly to the Murata ABZ (via the break out / CN2 and CN3).

As a start I have externally powered the ABZ. I expected the ABZ to send out LoRa messages as it does when connecting the Disco board via USB. However there are no LoRa message getting out. What am I missing here? Suggestions are appreciated

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[Tesla DeLorean]

Posted on July 05, 2017 at 17:14

Where exactly are you inserting power? You'll need a lot more specificity here for me to understand what you're doing or have achieved.

Look at the state of the NRST signal.

For debugging without an debugger, consider outputting telemetry via a USART so you have some means of observation to understand what is happening.

[Jeroen deBuffel]

Posted on July 05, 2017 at 21:40

Thanks. I did power the ABZ via 2 different manner:

1> 3 batteries -> LED7 turned ON (red)

2> Via VCC_MCU / VDD_RF / and USB VDD pins on CN2 -> LED7 turned ON (red)

Further I did not change anything to the disco board. Tomorrow I will connect the USART and check the NRST (too late now over here)

[Jeroen deBuffel]

Posted on July 13, 2017 at 13:37

When connecting via external power supply (battery e.g) the MCU_nRST remains 'low'. After feeding the MCU_nRST with 3.3V the ABZ started and the LoRa messages were sent out. USART I am working on ... thanks Clive!

[Jeroen deBuffel]

Posted on July 13, 2017 at 17:36

External powering is working fine.

What I want to do next is to be able to send commands to the ABZ via USART. Have done the following:

1> Uploaded AT_Slave software (from STM32CubeExpansion sw (v1.1.1) to the disco board

2> Connected another board (acting as 'AT master') directly to the LRWAN disco board.

      Using USART1_RX (PA10) and USART1_TX (PA9)

3> Send AT commands to the LRWAN1 disco board (9600, 8bits, no parity, 1 stopbit)

I see no serial response coming from the LRWAN board. So I am wondering if my setup is correct?

[Tesla DeLorean]

Posted on July 13, 2017 at 17:53

You'd have to modify the firmware. The build as provided uses LPUART1 on PA2/PA3 (ie VCP/SHIELD connection)

[Jeroen deBuffel]

Posted on July 13, 2017 at 19:44

Guess you are familiar with these boards 🙂 

Made some changes In \LoRa\AT_Slave\inc\mlm32l0xx_hw_conf.h (see below). Will continue to test tonight. So far no feedback on AT commands ...

// Jeroen 13-7-2017

♯ define UARTX_TX_PIN                    GPIO_PIN_9

♯ define UARTX_TX_GPIO_PORT    GPIOA ♯ define UARTX_TX_AF                     GPIO_AF4_USART1 ♯ define UARTX_RX_PIN                    GPIO_PIN_10 ♯ define UARTX_RX_GPIO_PORT    GPIOA ♯ define UARTX_RX_AF                     GPIO_AF4_USART1

// Original code

// ♯ define UARTX_TX_PIN                    GPIO_PIN_2

// ♯ define UARTX_TX_GPIO_PORT    GPIOA// ♯ define UARTX_TX_AF                     GPIO_AF6_LPUART1// ♯ define UARTX_RX_PIN                    GPIO_PIN_3// ♯ define UARTX_RX_GPIO_PORT    GPIOA// ♯ define UARTX_RX_AF                     GPIO_AF6_LPUART1//

In the end I might want to use another MCU to control the ST ABZ LoRa board. So trying to get this working ...

[Jeroen deBuffel]

Posted on July 14, 2017 at 16:07

I got the serial connection working when I connect to PA2 and PA3 (this is the default in the LoRa software).

Have tried to 'activate' to use USART1 (PA9 / PA10) -> no result. Seems that the code is build around LL_LPUART and a simple change as I indicated above does not work.

So I tried to configure for LPUART1 and activate it on another port (see below). However when I change the code in AT_Slave\inc\mlm32l0xx_hw_conf.h file and connect serial RX / TX to use LPUART1 on PB13 and PB14 I do not receive anything

&sharpdefine UARTX_TX_PIN                    GPIO_PIN_13

&sharpdefine UARTX_TX_GPIO_PORT    GPIOB&sharpdefine UARTX_TX_AF                     GPIO_AF4_LPUART1&sharpdefine UARTX_RX_PIN                   GPIO_PIN_14&sharpdefine UARTX_RX_GPIO_PORT   GPIOB&sharpdefine UARTX_RX_AF                    GPIO_AF4_LPUART1

I am trying to understand why it is not working ...

[Tesla DeLorean]

Posted on July 14, 2017 at 16:47

>>Guess you are familiar with these boards 🙂 

I have a bunch of them doing point-to-point communication, about 3KM LoS without much effort.

Not using them in AT Modem modes.

>>In the end I might want to use another MCU to control the ST ABZ LoRa board. So trying to get this working 

The CPU has quite a lot of FLASH/RAM for an L0 part, a lot of applications will fit without additional micro.

>>I am trying to understand why it is not working ...

Must do all the UART init code/defines, not just select pins. Clocks for UART, peripheral itself, IRQ Handlers, etc.

[Jeroen deBuffel]

Posted on July 14, 2017 at 18:15

>>Guess you are familiar with these boards 🙂 

I have a bunch of them doing point-to-point communication, about 3KM LoS without much effort.

Not using them in AT Modem modes.

>> Same here / our community installed a number of GWs. Many LoRa nodes active (based on RFM95 and RN2483) - now trying to get some stuff working with the ABZ.

With LoS (standing on top of a roof (height of 60m) -> max distance I reached was 64 kilometer :-))

>>In the end I might want to use another MCU to control the ST ABZ LoRa board. So trying to get this working 

The CPU has quite a lot of FLASH/RAM for an L0 part, a lot of applications will fit without additional micro.

>> Yes I know. In case I want to hook the LoRa nodes up to the operator network you are not allowed to have your own firmware installed :-(.

>> That is why I am looking at the AT option.

>>I am trying to understand why it is not working ...

Must do all the UART init code/defines, not just select pins. Clocks for UART, peripheral itself, IRQ Handlers, etc.

>> Yep and I was hoping the code would have that included .... some work to be done

Thanks again for your help!