Go to advanced search

by Schnoogle
Fri Dec 21, 2018 5:19 pm
Forum: Bare metal, Assembly language
Topic: Low voltage detection, read voltage level
Replies: 2
Views: 1000

Re: Low voltage detection, read voltage level

Hi Ultibo,

well thx for the reply. This seem to be what I was looking for. I'll try this.

BR
Schnoogle
by Schnoogle
Thu Dec 20, 2018 10:42 am
Forum: Bare metal, Assembly language
Topic: How to find the address of gpio in raspberry pi zero
Replies: 11
Views: 1488

Re: How to find the address of gpio in raspberry pi zero

Hi, well you are right with the GPIO base address being 0x20200000 - but only on RPi 1 and 2 as far as I'm aware. From RPi 3 onwards it's 0x3F200000 The document provided gives you pretty much all the register addresses to drive GPIO propperly. Whether you access those addresses with ARM-ASM or C do...
by Schnoogle
Thu Dec 20, 2018 8:21 am
Forum: Bare metal, Assembly language
Topic: How to find the address of gpio in raspberry pi zero
Replies: 11
Views: 1488

Re: How to find the address of gpio in raspberry pi zero

Hi dharanivel, I guess this documentation: https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf is a very good starting point. However, the memory addresses mentioned in this document differ depending on the RPi model you are using. If you do program in bare metal assembly tha...
by Schnoogle
Thu Dec 20, 2018 8:14 am
Forum: Bare metal, Assembly language
Topic: Low voltage detection, read voltage level
Replies: 2
Views: 1000

Low voltage detection, read voltage level

Hi there, I've seen in the linux device tree for RPi that the GPIO35 seem to indicate low voltage in case the RPi is driven by battery. Is this GPIO also mapped to low voltage indication in baremetal? If this is not the case, is there any way to detect voltage drops or to retrieve voltage levels the...
by Schnoogle
Thu Dec 13, 2018 12:41 pm
Forum: Bare metal, Assembly language
Topic: UART0, UART1, Blutetooth and WiFi interaction on Raspberry Pi 3 Model B+
Replies: 2
Views: 904

Re: UART0, UART1, Blutetooth and WiFi interaction on Raspberry Pi 3 Model B+

Hi dublevsky, whether you are on the right forum o not depends on whether you are planning to do baremetal implementation or just building applications on top of Linux. Assuming this forum is the right place for you and you are planning to do some baremetal stuff I might be able to share some of my ...
by Schnoogle
Thu Nov 08, 2018 11:34 am
Forum: Bare metal, Assembly language
Topic: Problem with BCM2835 datasheet
Replies: 7
Views: 2450

Re: Problem with BCM2835 datasheet

Hi kokos, I'm only guessing but for me it looks like bit's 11:10 are meant to be reserved... And than the counting in the table is just wrong.... 5:0 -> Bit count 6 -> Busy 7 -> RX Empty 8 -> TX Empty 9 -> TX Full You could cross check this by yourself by putting the content of this register to UART...
by Schnoogle
Mon Nov 05, 2018 4:10 pm
Forum: Bare metal, Assembly language
Topic: Raspberry pi zero w bare metal interrupt from gpio
Replies: 1
Views: 1188

Re: Raspberry pi zero w bare metal interrupt from gpio

Hi Moahrs, I'm not sure how compatible PI Zero and PI 3 are in this regard. but I did recently implemented GPIO IRQ handling on my RPi 3 with great success. Let's see how I solved this... 1. I assume you have setup all IRQ vectors properly during initial baremetal boot-up and you did write a common ...
by Schnoogle
Wed Aug 01, 2018 6:32 pm
Forum: Bare metal, Assembly language
Topic: I can't get hardware PWM to work on PI3
Replies: 3
Views: 1454

Re: I can't get hardware PWM to work on PI3

Hi bzt, thanks for trying to help me out with this issue. From the documents I've seen so far for the RPi clocks, the busy flag mean, that the clock is running and creates clock cycles based on the current setting. To change the settings you need to stop the clock, wait until the busy flag is clear ...
by Schnoogle
Tue Jul 17, 2018 7:51 pm
Forum: Bare metal, Assembly language
Topic: When compiling for Pi3 in Arch32 enabling VFP
Replies: 12
Views: 3668

Re: When compiling for Pi3 in Arch32 enabling VFP

Hi,

well, than the issue might be your -mcpu flag set to cortex-a53 ... I’m not using this one. Instead I do -mtune=cortex-a53 together with -march=armv8-a

Hope this helps.
BR,
Schnoogle
by Schnoogle
Mon Jul 16, 2018 8:47 am
Forum: Bare metal, Assembly language
Topic: When compiling for Pi3 in Arch32 enabling VFP
Replies: 12
Views: 3668

Re: When compiling for Pi3 in Arch32 enabling VFP

Hi sheroy,

as far as 8 can see you are using the -mfpu directive twice.
I’m also using arm-none-eabi to cross compile my bare metal stuff.

I’m using this settings:
-mfpu=neon-fp-armv8 -mfloat-abi=hard -march=armv8-a

and the compiler does except and compile the fmxr instruction.

BR
Schnoogle
by Schnoogle
Wed Jul 11, 2018 11:29 pm
Forum: Bare metal, Assembly language
Topic: I can't get hardware PWM to work on PI3
Replies: 3
Views: 1454

I can't get hardware PWM to work on PI3

Hi there, before I loos all my hair ;) I just try to find a possible answer here... I'm running in baremetal and try to get the hardware PWM running. I've checked how wiringPI and circle does implement the same and adopt is, but neither a LED nor the Osszi is giving any output on the pins where PWM ...
by Schnoogle
Sun Jul 01, 2018 7:00 am
Forum: Bare metal, Assembly language
Topic: Bare metal hang when reading from SD Card?
Replies: 23
Views: 1845

Re: Bare metal hang when reading from SD Card?

Hi there, if I‘m Not mistaken the line 25 is accessing the content of the address master_boot_record+0x1C6 ... This is actually not a 4 Byte aligned address. As far as I know the RPi(ARM) is initially only accepting proper aligned memory access. You could allow un-aligned access during your boot up....
by Schnoogle
Wed Jun 20, 2018 8:02 pm
Forum: Bare metal, Assembly language
Topic: Assembly / C IDE that can remote compile / debug / run
Replies: 5
Views: 1106

Re: Assembly / C IDE that can remote compile / debug / run

Hi Cromulent, weil Site this is possible to some extend. I’m running Windows 10 with eclipse for C/C++/Assembly I’m using a cross compile toolchain tu directly compile on the windows machine. Than you are free how to transfer to your Pi. When Linux is running on it you may choose ssh and can also co...
by Schnoogle
Wed Jun 13, 2018 2:53 pm
Forum: Bare metal, Assembly language
Topic: [Partly-Solved] VCHIQ/MMAL Camera access
Replies: 28
Views: 3216

Re: [Partly-Solved] VCHIQ/MMAL Camera access

Hi Ultibo, well, the VCHIQ is setting up some memory space which will be shared between GPU and ARM. When sending a new message to VCHIQ this memory space is filled with the appropriate data, and a in specific part of it - the SHARED_STATE - flag will be set that there is new data available and the ...
by Schnoogle
Fri Jun 08, 2018 9:03 pm
Forum: Bare metal, Assembly language
Topic: [Partly-Solved] VCHIQ/MMAL Camera access
Replies: 28
Views: 3216

Re: [Partly-Solved] VCHIQ/MMAL Camera access

Hi Ultibo, well I'm using semaphores and spinlocks. As far as I'm aware mutex is quite similar to the spinlock approach and ensures propper cross core handling of memory access...But to answer your question, there is no specific initialization for the spinlock/mutex necessary to be called before the...
by Schnoogle
Tue Jun 05, 2018 6:53 pm
Forum: Bare metal, Assembly language
Topic: multi-core shared memory communication
Replies: 15
Views: 3424

Re: multi-core shared memory communication

Hi ChrisYin, well as far as I'm aware the four cores are sharing the same memory - so they are sharing the same page table. I've all 4 cores running with active MMU. The most important thing from my point of view is to ensure that the cores are lifted off one after the other. So I introduced a core-...
by Schnoogle
Tue Jun 05, 2018 6:03 pm
Forum: Bare metal, Assembly language
Topic: [Partly-Solved] VCHIQ/MMAL Camera access
Replies: 28
Views: 3216

Re: [Partly-Solved] VCHIQ/MMAL Camera access

Hey LdB, thanks for your efforts. I'll try to see if I can find the root cause. The thing is, that the VCHIQ bulk transfer isn't even initiated. It stopps already when calling the VCHIQ interface with the message: MMAL_WORKER_BUFFER_FROM_HOST. This would usually trigger the VCHIQ callback which is f...
by Schnoogle
Mon Jun 04, 2018 7:52 pm
Forum: Bare metal, Assembly language
Topic: [Partly-Solved] VCHIQ/MMAL Camera access
Replies: 28
Views: 3216

Re: [Partly-Solved] VCHIQ/MMAL Camera access

Hi LdB, thx for constantly supporting me here :)... I tried your recommendation. The memory for the payload is now allocated on GPU side. The result is still the same. For 128x100 capture it works, for 128x128 it doesn't. The payload buffer is allocated at 0x3E3CD000 and the GPU memory is reported t...
by Schnoogle
Mon Jun 04, 2018 5:25 pm
Forum: Bare metal, Assembly language
Topic: [Partly-Solved] VCHIQ/MMAL Camera access
Replies: 28
Views: 3216

Re: [Partly-Solved] VCHIQ/MMAL Camera access

Hi 6by9, thanls for those links, they give me also much of an insight into what's going on behind the scenes here. Hey LdB, well I do hope that there was no miss-understanding but I assume that you are talking about a more "real-baremetal" approach to accessing the camera? I do have an own VCHIQ/MMA...
by Schnoogle
Sun Jun 03, 2018 9:12 pm
Forum: Bare metal, Assembly language
Topic: [Partly-Solved] VCHIQ/MMAL Camera access
Replies: 28
Views: 3216

Re: [Partly-Solved] VCHIQ/MMAL Camera access

Hi LdB, thx for your tips. However, looking at the working and not working examples the difference between CAM_ISBE0 and CAM_ISBA1 is 1586304 :O :O When switching the image capture size I'll completely re-boot the Pi so there should not be any configuration from a previous run left... I'm not sure a...
by Schnoogle
Sun Jun 03, 2018 10:56 am
Forum: Bare metal, Assembly language
Topic: [Partly-Solved] VCHIQ/MMAL Camera access
Replies: 28
Views: 3216

Re: [Partly-Solved] VCHIQ/MMAL Camera access

Hey Ldb, so I dumped the UNICAM registers during the camera setup process everytime a VCHIQ message has been queued - befor the VC responded... As I can't ell much on the contents of the registers I'm not sure what they meen. However, I've comared them when setting up camera capture with 128x100 (wh...
by Schnoogle
Sun Jun 03, 2018 9:34 am
Forum: Bare metal, Assembly language
Topic: [Partly-Solved] VCHIQ/MMAL Camera access
Replies: 28
Views: 3216

Re: [Partly-Solved] VCHIQ/MMAL Camera access

Thanks ultibo and ldb, fortunately I'v now the GPU ram reported correctly. :) The config.txt looks like this now: start_x=1 gpu_mem=128 disable_l2cache=1 enable_l2cache=0 But still the same issue. I've the MMU setup with L1 caching active. I've no clue how to get L2 caches setup but the disable_l2ca...
by Schnoogle
Sat Jun 02, 2018 8:09 pm
Forum: Bare metal, Assembly language
Topic: [Partly-Solved] VCHIQ/MMAL Camera access
Replies: 28
Views: 3216

Re: [Partly-Solved] VCHIQ/MMAL Camera access

Hi Ldb,

thx for your quick response. Unfortunately this does not solve my issue.
My config file now looks like this:

Code: Select all

start_file=start_x.elf
start_fixup=fixup_x.dat
disable_l2cache=1
gpu_mem=256
Is there any VC trace option one could activiate in the config.txt file ?

BR,
Schnoogle
by Schnoogle
Sat Jun 02, 2018 4:46 pm
Forum: Bare metal, Assembly language
Topic: [Partly-Solved] VCHIQ/MMAL Camera access
Replies: 28
Views: 3216

Re: [Partly-Solved] VCHIQ/MMAL Camera access

Hi there, unfortunatley the luck was not long on my side - in case it has anything to do with luck ;) The camera access and capturing as well as displaying on the screen runs quite well as far as I can tell. BUT: Only for small capture sizes. I started experimenting with RGB16 and sizes of 32x32 and...
by Schnoogle
Sun May 27, 2018 6:28 pm
Forum: Bare metal, Assembly language
Topic: [Partly-Solved] VCHIQ/MMAL Camera access
Replies: 28
Views: 3216

Re: VCHIQ/MMAL Camera access

Hey Ultibo, thanks again for your explanation. After some time off and vacation I was able to continue on this topic ;). With your details I was able to get it working. I'm now able to get the data with the bulk request from the camera :) Thanks a lot.... I'll send at least a virtual beer from Germa...

Go to advanced search