Memfault State of IoT Report

How to use STM32 to read signal from the PS2 hand controller through SPI protocol?

Started by Namcrazy37 2 years ago6 replieslatest reply 2 years ago669 views

I have a project where I need to connect a PS2 hand controller to my microcontroller (STM32F4 series) to control a robot. I want to use the controller to read the signals from the buttons and joystick on that hand controller via SPI communication using DMA to avoid missing events from PS2. Then, I can control my robot's direction, speed, and switch between several operating modes. 

Currently, I am first building a small program to test the signal transmission between the microcontroller and the ps2 controller. I created variables for each button on the handler, and then each time I press a button, the corresponding variable should increase by one. However, it seems that my MCU cannot receive the signal from the ps2 yet because when I connect and press the buttons, the program still cannot run as expected. I have also attached my main code: ps2_controller_polling.txt.

I also attached the ps2's data frame format that i found for anyone who wants to refer: PS2_msg_format.gif.

I'm still fairly new to embedded programming so can someone help me with suggestions on where maybe I'm going wrong, please? 

Thank you so much!

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Reply by DilbertoJuly 13, 2022

Hi, @Namcrazy37!

   Using STM32CubeIDE can do all the hardware configurations for you, and, better yet, it can flag hardware configuration errors and even auto-correct them.

   Have you verified whether your hardware configuration is all ok?

   Besides that, it's worthwhile to verify the circuit itself. SPI uses a separate pin to enable the peripheral. Are you ( or the HAL ) driving it?

   Hope to have helped.


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Reply by Namcrazy37July 13, 2022

Yes, I'm using STM32CUBEMX for the configuration. I set the mode for my SPI as full-duplex master and NSS signal type as Software. Here is my other SPI configuration: 

I have also used a randomly separated GPIO pin as the Slave Select pin for my SPI. Can you refer t my main code to know better what I might be going wrong, please?

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Reply by VadimBJuly 13, 2022

In the current state, I don't see how you program can even be built. You declare static functions but don't define them. The linker should scream.

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Reply by faustoRaicamJuly 13, 2022


why doy you write this "spi_disable;" before infinite loop?

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Reply by DilbertoJuly 13, 2022

Hi, faustoRaicam!

   I think the O. P. wanted to write spi_enable;

   It should be a type of "finger addressing error"   :-)


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Reply by SpiderKennyJuly 13, 2022

You need to change spi_disable; to spi_enable.

Also, when reading the values for the button, you should use bit-wise checking not byte-wise. HINT: What happens if you press TWO, THREE or FOUR buttons at the same time?

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