How to use external interrupts at the raspberry pi

Hi,

First of all, i am apologise for my english. :)

I try to realize balance bot throught the simulink. I am using Raspberry Pi support package from simulink. I need for read from incremental sensors which is at DC motors, but GPIO READ is too slow. From specific frequencies simulink canot catch signal. I need that signal for identify speed or position of balance bot. I think and i know. There is solution made Sfunction using C++ program. But i dont know how.I have C++ which can read with externa interrupts.Have anybody solution?

[Nirmalkumar Doreraju]

Hi Petr,

Currently external interrupt blocks are not provided as a part of Simulink support package for Raspberry Pi, but nonetheless it will be available in future releases. In the meantime, you can follow this link to understand what S-Functions are and how to create blocks with them.

https://in.mathworks.com/help/simulink/sfg/what-is-an-s-function.html

Thanks and Regards,

Nirmal

[Petr Mamula]

I understand there is way throught the S-Function, but it is out of my experiences make that block. I hope for anybody who solved this specific problem help me with Sblock, or give me usable block.

[Anna-Lena Carl]

Hello Nirmalkumar and Petr,

is there any news about the external interrupt blocks in Simulink support package for Raspberry Pi.

Besides, I tried to implement C S-function (like in the C code examples) and "mex" it. However, I am struggling with two things:

1. How can I addess the GPIOs? Is there any lib in the Simulink support package like pigpio, wiringPi, etc.? Or is there a different lib for C access to the pins?
2. Where to implement the interrupt function (such as gpioSetAlertFunc) in order to call the callback function at an appropriate point-in-time when the GPIO changes state?

Thanks

[Petr Mamula]

Hi,

Yes, there is one sulution, but it is a little bit tricky, but it work very well for me!

I bought ESP8266. Every pin of this MCU are an interrupt pin. I programed code for external interrupt.

For transfer data from ESP to Rpi i am using UART. Its easy to implement. Rpi sent any number to ESP, and after that ESP sent increment of pulses. I set the sampling time to 0.01s. With that knowlage you can calculate true velocity and position. There is not problem with bouncig or miss read. ESP have not problem with two motors--> 4 input signals.

I dont used any libraries.

I know, this is not what you want to read, but as i said, it wok!

Maximal frequency of interrupt is 1,2kHz.

[Aditya Patil]

Hi Petr, feel free to post your solution as an answer, so that it helps others in the future