How to use M4 processor?

I want to study heterogeneous systems.
I must run C/C++ programs on M4, replacing to write arduino programs.
How to do?


Thanks

 

Perhaps Tim Michals can give you guidance http://allthingsembedded.blogspot.it/
http://www.udoo.org/forum/threads/mcc-shared-memory-address.3001/

 

I would suggest :

1. Spend some time understanding the cortex m3/m4 boot sequence (ie vector tables etc) if you are new to the subject.
2. Review chapters 2,13,52,61 im6sx reference manual as they indicate differences/features for supporting A9 + M4.
3. Understand how uboot is used to load & start an m4 program
4. You can now develop using FreeRTOS on the imx6x, more information can found in the here. Download the RTOS tar and it contain docs + samples. Some of the samples require modification to work on the NEO but that's part of the learning curve. I have built some of them of so they will work.

 

FYI; to use rpmsg; you must patch the kernel; I was thinking of putting the patches at rpmsg-neo.

 

Hi,

sorry for reopening an old thread, but I'm struggling with rpmsg on udoobuntu (udoo neo). My ultimate goal is to have udoobuntu (A9) + freertos (M4), both communicating using rpmsg. Can somebody point out all the necessary changes that have to be done on udoobuntu side? So far I have crosscompiled a few kernel modules (virtio, virtio_ring, virtio_rpmsg_bus, rpmsg-neo, imx_rpmsg_tty, imx_rpmsg_pingpong) - the last two taken from http://git.freescale.com/git/cgit.cgi/imx/linux-imx.git/tree/drivers/rpmsg?h=imx_3.14.52_1.1.0_ga. However, after loading any of the rpmsg-neo or imx_rpmsg_* modules I have no rpmsg device in /dev. So I suppose that I am still missing something - maybe dtb or kernel modification?

Thanks.

 

@aprchal, I've been working on other platforms for the past year. I did some patches a while ago, but I think it would make more sense to use the latest kernel with patches or https://github.com/fmntf/linux_kernel/tree/4.1.15_1.x-udoo

I'm checking into the status rpmsg at this time with 4.1.15 with Neo.

 

@aprchal
I'm using the kernel mentioned by @tcmichals. The problem is, that the dtb files didn't have entries for rpmsg. Even mor frustrating was, that dmesg | grep rpmsg produced this:
[ 0.147736] imx rpmsg driver is registered.
'imx6sx.dtsi' should contain a disabled entry.
I added
&rpmsg{
status = "okay";
};
Now I dmesg | grep rpmsg returns an additional entry:
[ 0.147631] virtio_rpmsg_bus virtio0: rpmsg host is online
[ 0.147736] imx rpmsg driver is registered.
Now the examples are working. I hope this helps.