Irq error when trying to initialise 2 ultrasonic sensors

Mbed OS
,
1

Hi, I’m trying to code a system that uses two HC_SR04 ultrasonic distance sensors and a Nucleo F303RE board.

I’m using this library: https://os.mbed.com/users/JohnnyK/code/HC_SR04_Ultrasonic_Library/
written by @JohnnyK (thankyou!)

code, declaring instances:

 ultrasonic front_USS(FTRIG, FECHO, 100ms, 1s, &f_dist);   
 ultrasonic left_USS(LTRIG, LECHO, 100ms, 1s, &l_dist); ```

The code compiles fine, but when I run it the serial just shows this error:
> ++ MbedOS Error Info ++
> Error Status: 0x80FF0100 Code: 256 Module: 255
> Error Message: Fatal Run-time error
> Location: 0x80058FD
> Error Value: 0x0
> Current Thread: main Id: 0x20001F2C Entry: 0x8006C47 StackSize: 0x1000 StackMem: 0x20000518 SP: 0x2000140C 
> For more info, visit: https://mbed.com/s/error?error=0x80FF0100&tgt=NUCLEO_F303RE
> -- MbedOS Error Info --
> InterruptIn error: irq channel conflict

The code runs fine for either of the sensors on their own. but it doesn't like having both decalared at once.
I assume the IRQ channel conflict is to do with having timeouts/interrupts happening for both sensors at once. 

Is there a way to get this code working for multiple ultrasonic sensors?

Thankyou
2

Hello,

first of all, the library was not made by me, I did just update of few lines to be compatible with MbedOS 6+ (it is in decription) :slight_smile:

I do no see used pins, but probably…

BR, Jan

3

Hi Jan,

Thanks for your response, here are the pins I’m using on the Nucleo F303RE:

#define FTRIG D9
#define FECHO D10
#define LTRIG D11
#define LECHO D12

//f_dist() and l_dist() defined here

ultrasonic front_USS(FTRIG, FECHO, 100ms, 1s, &f_dist);
ultrasonic left_USS(LTRIG, LECHO, 100ms, 1s, &l_dist);

from:

On STM32 external interrupts share lines.
All PA_1, PB_1, PC_1 … PG_1 share one single line 1
All PA_2, PB_2, PC_2 … PG_2 share one single line 2
All PA_N, PB_N, PC_2 … PG_N share one single line N
And even EXTI may be shared between lines 5 to 9

So user should only consider using one EXTI per GPIO bank and carefully review selection

from the nucleo pinout: D9-D12 = PC_7, PB_6, PA_7, PA_6
image

does this mean the error is being caused by using pins ending in the same number (6 and 7)?

4

Yes, and it could work when you just rotate two wires (also on hardware side ofc :slight_smile: )

#define FTRIG D9
#define FECHO D10
//#define LTRIG D11
//#define LECHO D12
#define LTRIG D12
#define LECHO D11

BR, Jan

1 Like
5

Thanks I’ll give this a try.

Unfortunately the board has stopped uploading code altogether now, I think I might have broken it trying to power it via external battery :upside_down_face:

6

Yeah, it is possible, I burned-out on-board voltage regulators of Nucleo-L152RE in the past.

BR, Jan