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by django013
Fri May 19, 2017 7:40 am
Forum: Bare metal, Assembly language
Topic: Circle - C++ bare metal environment (with USB)
Replies: 238
Views: 64335

Re: Circle - C++ bare metal environment (with USB)

Don't know, whether I got you right. I think, tristate has nothing to do with output frequency of a pin. It is used to disable the output amplifier in case the pin is switched to input mode. The delay, or what you call latch results in the difference of gpio frequency and core frequency. I have no i...
by django013
Thu May 18, 2017 11:54 am
Forum: Bare metal, Assembly language
Topic: Circle - C++ bare metal environment (with USB)
Replies: 238
Views: 64335

Re: Circle - C++ bare metal environment (with USB)

I think, you have to take a platform as it is, at least when you have a project and have to start with it now. That means, you cannot tell: "The hardware is great, but the documentation is poor." Documentation will not change, because of this. Yes, you're right. I didn't want to argue about platfor...
by django013
Thu May 18, 2017 4:11 am
Forum: Bare metal, Assembly language
Topic: Circle - C++ bare metal environment (with USB)
Replies: 238
Views: 64335

Re: Circle - C++ bare metal environment (with USB)

Thank you for the big explanations :) You should know, that bare metal is not the favourite programming model for the RPi. Please - don't take me for stupid. I saw lot of rpi projects and the raspberry homepage, which is targeted to kiddies and not to serious programmers ... Anyway - the circle proj...
by django013
Wed May 17, 2017 11:39 am
Forum: Bare metal, Assembly language
Topic: Circle - C++ bare metal environment (with USB)
Replies: 238
Views: 64335

Re: Circle - C++ bare metal environment (with USB)

Hi, if the naming scheme st uses is not invented by them, it should be something like APB1 .. n which means something like ARM Peripheral Bus or the like ;) As st-chips have various APB clocks, that might be true for bcm2837 and some pins might clock at higher speed if used by an alternate function ...
by django013
Wed May 17, 2017 8:05 am
Forum: Bare metal, Assembly language
Topic: Circle - C++ bare metal environment (with USB)
Replies: 238
Views: 64335

Re: Circle - C++ bare metal environment (with USB)

Hi, your research is not far from my expectations. When I look at an stm32f407 - that can drive gpio pins with half the system clock. No matter if you would be able to write an opcode, that toggles a pin at system clock, the pin-output-subsystem is not. So no matter whether you call it waitstates or...
by django013
Wed May 17, 2017 3:15 am
Forum: Bare metal, Assembly language
Topic: Circle - C++ bare metal environment (with USB)
Replies: 238
Views: 64335

Re: Circle - C++ bare metal environment (with USB)

Hi, very interesting your work! But that's half of the story only too. What about the frequency setup? I guess, if you drive the pins outside the spec, signal quality might not be usable/reliable. St has a very nice tool to setup pins and clock tree configuration, so all dividers and constraints are...
by django013
Tue May 16, 2017 8:33 am
Forum: Bare metal, Assembly language
Topic: Circle - C++ bare metal environment (with USB)
Replies: 238
Views: 64335

Re: Circle - C++ bare metal environment (with USB)

Hi, I completely agree - they didn't tell the whole story. Looking at the sources it looks to my, that they run the build using linux. But with linux you don't have jitterfree execution time. And there's a huge difference, whether you run 32bit linux or 64bit ... And I agree too on the impact the co...
by django013
Tue May 16, 2017 3:34 am
Forum: Bare metal, Assembly language
Topic: Circle - C++ bare metal environment (with USB)
Replies: 238
Views: 64335

Re: Circle - C++ bare metal environment (with USB)

I don't think the GPIO block will be much faster on the RPi 3 or in 64-bit mode. looking on timer access only doesn't require 64bit or single instruction access. But taking the sum of calculations, that have to be worked out between pin-changes shows, that in 64bit mode the calculation takes less c...
by django013
Mon May 15, 2017 2:49 pm
Forum: Bare metal, Assembly language
Topic: Circle - C++ bare metal environment (with USB)
Replies: 238
Views: 64335

Re: Circle - C++ bare metal environment (with USB)

Hi, thank you for your patience and support! QA7 is very exciting. Thanks! I don't know anything about multicore programming, so there's much new to me. ... by the way: do you have any links to learn multicore programming? I know a bit of stm32 - and the newer devices are able to run timers at syste...
by django013
Sun May 14, 2017 7:09 am
Forum: Bare metal, Assembly language
Topic: Circle - C++ bare metal environment (with USB)
Replies: 238
Views: 64335

Re: Circle - C++ bare metal environment (with USB)

Yes, but the address of this register is not 64-bit aligned. See page 172 of the referenced document. As I understand it, this means the memory system has to do two 32-bit accesses to get the 64-bit contents of the register. Duh! What a mess! You're right! What a stupid misconception from the proce...
by django013
Sat May 13, 2017 6:02 am
Forum: Bare metal, Assembly language
Topic: Circle - C++ bare metal environment (with USB)
Replies: 238
Views: 64335

Re: Circle - C++ bare metal environment (with USB)

Hi, thank you for your fast reply and the link! There is a 64-bit system clock register in the BCM283[567] which is incremented by one each microsecond and which can be read from each core. Circle only uses the lower 32-bits of this register. Well, on 64bit systems reading a 64bit register should be...
by django013
Fri May 12, 2017 7:24 am
Forum: Bare metal, Assembly language
Topic: Circle - C++ bare metal environment (with USB)
Replies: 238
Views: 64335

Re: Circle - C++ bare metal environment (with USB)

Hi, I just discovered your work and after a quick look I have some questions. I'm mainly interested in the 64bit port :) The raspi 3 runs a max frequency of 1.2GHz, so what is the fastest timer to setup? You wrote that core 0 handles all interrupt responses ... From linux kernel I read about "jiffie...
by django013
Fri Apr 07, 2017 11:32 am
Forum: Linux Kernel
Topic: Xenomai Packages
Replies: 24
Views: 31160

Re: Xenomai Packages

Hello,

does anybody has xenomai-patch running at arm64 kernel?
If so, where can I find instructions to get such combination to work?
by django013
Fri Apr 07, 2017 11:07 am
Forum: Device Tree
Topic: kernel 4.11 boots with dtb of kernel 4.5 - but not current
Replies: 2
Views: 1024

Re: kernel 4.11 boots with dtb of kernel 4.5 - but not curre

Hi,

does the device-tree differ between aarch32/aarch64?
by django013
Fri Apr 07, 2017 8:23 am
Forum: Device Tree
Topic: kernel 4.11 boots with dtb of kernel 4.5 - but not current
Replies: 2
Views: 1024

kernel 4.11 boots with dtb of kernel 4.5 - but not current

Hello, I started on arm64 with the debian-image from xylnao and suceeded in updating the whole system, building a 4.11 kernel having now a rpi3 with debian sid starting headless with ssh-access. Everything fine so far - but I have to use the device-tree-blob he provided. Trying the device-tree-blob,...
by django013
Tue Apr 04, 2017 12:30 pm
Forum: Advanced users
Topic: arm64 and PI3 - no success
Replies: 0
Views: 493

arm64 and PI3 - no success

Hello, I guess, I miss something on the way doing it. I read that several guys have running arm64 systems, so I think, it should be possible. What have I done: I startet with setting up an arm64-system space with qemu-debootstrap on my debian desktop. Inside that chroot-system, I build a kernel from...
by django013
Sun Apr 02, 2017 1:10 pm
Forum: Raspbian
Topic: Raspbian Jessie (64bit) for RPi3?
Replies: 145
Views: 134790

Re: Raspbian Jessie (64bit) for RPi3?

I run sysbench on my Pi3 with these results: time sysbench --test=cpu --num-threads=4 --cpu-max-prime=20000 run sysbench 0.4.12: multi-threaded system evaluation benchmark Running the test with following options: Number of threads: 4 Doing CPU performance benchmark Threads started! Done. Maximum pri...
by django013
Thu Mar 30, 2017 4:12 am
Forum: Troubleshooting
Topic: cpuset fails [resolved]
Replies: 6
Views: 1080

Re: cpuset fails [resolved]

I got help from the original debian folks :)

cpuset is disabled by default on raspbian and the error message is misleading.
Enabling cpuset in cmdline.txt is the solution :)
by django013
Thu Mar 30, 2017 3:21 am
Forum: Troubleshooting
Topic: cpuset fails [resolved]
Replies: 6
Views: 1080

Re: cpuset fails

How have you done that?

Code: Select all

sudo passwd
su -
"su -" executes a login shell

... but I do my testing via ssh, so the raspberry has only Ethernet and power connected.
with ssh
by django013
Wed Mar 29, 2017 1:11 pm
Forum: Troubleshooting
Topic: cpuset fails [resolved]
Replies: 6
Views: 1080

Re: cpuset fails

???

why should I use sudo, when logged in as root?
by django013
Wed Mar 29, 2017 10:22 am
Forum: Troubleshooting
Topic: cpuset fails [resolved]
Replies: 6
Views: 1080

cpuset fails [resolved]

Hello, I'm doing my first steps on raspberry (model 3) and raspbian stretch and wanted to try reserving some cpu cores for my app. cpuset seems to be the tool of choice. kernel is Linux version 4.4.50-v7+ ([email protected]) (gcc version 4.9.3 (crosstool-NG crosstool-ng-1.22.0-88-g8460611) ) #970 S...

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