I’ve had trouble with this set up before, seems to me everytime I try and set up a board the first time it never works. However when I come back for another pass things are usually very straight forward, today my experience with the MCXN236 has been the same.

Perhaps I was in a rush, perhaps I need more patience?

Regardless, let’s actually explore. My objective today is to hook up a camera to the MCXN236 specifically the OV5640. Then try and see if we can achieve some UVC video as well, see if we can use libmpix to do some signal processing on the videos themselves.

Let’s begin.

Setup

To start with lets get the board and try and run some zephyr samples on it.

  1. Install and setup LinkServer tools as linked in the Zephyr Board Page
  2. Build and flash a basic blinky application onto the board 
    west build -b frdm_mcxn236 zephyr/samples/basic/blinky --pristine
...
west flash
  3. The above should give you a red blinking, not very exciting, I know!
  4. Acquire the OV5640 Camera module and have it ready, infact you can connect it up the board as follows, connecting the camera should light up the green LED on the back of the camera module. This means power good.

Board and Camera Connected

Ok so thats our hardware all setup, let’s see if we can configure the camera and get some captures from it.

Overlays & Configuration

In order for this to work with as little effort as possible lets first ensure that a few items exist.

  1. A video driver for this MCU and indeed we have a SDMA Driver
  2. A driver for our image sensor module OV5640 Driver

With these 2 now the issue becomes plumbing the data from the image sensor via sdma to some chosen zephyr,camera node, this should enable us to get the video subsytem working

  1. Setup the camera itself on the dvp_i2c block as follows
&dvp_20pin_i2c {
	ov5640: ov5640@3c {
		compatible = "ovti,ov5640";
		reg = <0x3c>
		#reset-gpios
		#power-down-gpios

		port {
			ov5640_ep_out: endpoint {
				remote_endpoint_label = "ov5640_sdma_ep_in";
			};
		};
	};
};
  1. Send the camera data from the dvp_i2c block to the dvp_sdma block as follows
&dvp_20pin_interface {
	status = "okay";

	port {
		ov5640_sdma_ep_in: endpoint {
			remote_endpoint_label = "ov5640_ep_out";
		};
	};
};
  1. Set the chosen zephyr,camera node.
#include <zephyr/dt-bindings/video/video-interfaces.h>

/ {
	/*Chosen cam node*/
	chosen {
		zephyr,console = &flexcomm0_lpuart0;
		zephyr,shell-uart = &flexcomm0_lpuart0;
		zephyr,camera = &dvp_20pin_interface;
	};
};

TODO: File an issue and likely work on a PR for this.

This all currently works, however it fails with the following when it is time to capture

*** Booting Zephyr OS build v4.2.0-4812-g48a9b04885cb ***
[00:00:00.125,000] <inf> main: Video device: video-sdma
[00:00:00.125,000] <inf> main: - Capabilities:
[00:00:00.125,000] <inf> main:   RGBP width [320; 320; 0] height [240; 240; 0]
[00:00:00.125,000] <err> main: Unable to retrieve video format

Device Emulation Reference

https://www.youtube.com/watch?v=usXCAXR2G_c

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