Processors Category - Page 1121 of 1122 - CNX Software

July 28, 2010May 12, 2018 by Jean-Luc Aufranc (CNXSoft) - No Comments

Enabling swap in embedded systems

If your embedded system running Linux does not have enough memory, you can enable swap to get more memory. However if your platform does not have MMU (Memory Management Unit) as is the case for Sigma Designs EM8620 series, it won’t support swap, so forget it. If your platform does have MMU, as is the case for many newer platforms such as Sigma Designs SMP8630, SMP8640 and SMP8650 series, you can enable swap support. First you’ll have to make sure swap support is enabled in your kernel:

CONFIG_SWAP=y
CONFIG_SWAP_PREFETCH=y

1 2	CONFIG_SWAP=y CONFIG_SWAP_PREFETCH=y

and swapon/swapoff is enabled in busybox. So for example if you have an IDE harddisk with the second partition configured as swap. (Use fdisk to create a partition and mkswap /dev/hda2 to initialize the partition), you can enable the swap as follows:

swapon /dev/hda2

1	swapon /dev/hda2

If you get out-of-memory killer kernel error, you can change the “swapiness” to avoid oom-killer to kick in.

echo 0 &gt; /proc/sys/vm/mapped

1	echo 0 > /proc/sys/vm/mapped

[…]

July 18, 2010December 20, 2016 by Jean-Luc Aufranc (CNXSoft) - 9 Comments

How to do a framebuffer screenshot

I’ll explain how to do framebuffer screenshots on 16-bit and 32-bit framebuffer. For 16-bit this is fully based on http://docs.blackfin.uclinux.org/doku.php?id=framebuffer Capturing screenshots Whatever the bit-depth of your framebuffer, the first step is to capture the frambuffer raw data on the board:

cat /dev/fb0 > screen.raw

1	cat /dev/fb0 > screen.raw

Now the you need to take the raw image, and convert it to a standard image format. This step depends on what type of display is there Converting 16-bit Framebuffer screenshot (RGB565) into png To convert the raw rgb data extracted from /dev/fb0, use iraw2png perl script

#!/usr/bin/perl -w

$w = shift || 240;
$h = shift || 320;
$pixels = $w * $h;

open OUT, "|pnmtopng" or die "Can't pipe pnmtopng: $!\n";

printf OUT "P6%d %d\n255\n", $w, $h;

while ((read STDIN, $raw, 2) and $pixels--) {
   $short = unpack('S', $raw);
   print OUT pack("C3",
      ($short & 0xf800) >> 8,
      ($short & 0x7e0) >> 3,
      ($short & 0x1f) << 3);
}

close OUT;

#!/usr/bin/perl -w

$w = shift || 240;

$h = shift || 320;

$pixels = $w * $h;

open OUT, "|pnmtopng" or die "Can't pipe pnmtopng: $!\n";

printf OUT "P6%d %d\n255\n", $w, $h;

while ((read STDIN, $raw, 2) and $pixels--) {

$short = unpack('S', $raw);

print OUT pack("C3",

($short & 0xf800) >> 8,

($short & 0x7e0) >> 3,

($short & 0x1f) << 3);

}

close OUT;

To do the conversion, type the following command in the host:

./iraw2png 640 480 < screen.raw > screen.png

1	./iraw2png 640 480 < screen.raw > screen.png

where 640 and 480 are respectively the width and height of your framebuffer. This has been tried on a 16-bit framebuffer on EM8620 series. Converting 32-bit Framebuffer screenshot (ARGB, RGBA, BGRA…) into png The solution proposed here is not as neat as the blackfin’s solution for 16-bit framebuffer, […]

July 11, 2010November 24, 2019 by Jean-Luc Aufranc (CNXSoft) - No Comments

uClinux kernel panic: Stack overflow

If you’re using ucLinux, you may get kernel panic errors coming out of nowhere. There may be several reasons (buffer overflow, out of memory..), but the most common is stack overflow for the process or one of the threads. To increase the stack size of a flat binary you’ll need to adjust the LDFLAGS as follows:

LDFLAGS+=-Wl,-elf2flt="-s65536"

1	LDFLAGS+=-Wl,-elf2flt="-s65536"

This will set the stack size to 64KB. To change the stack size of a thread (e.g. 32KB below), you’ll need to set the stack size attribute:

pthread_attr_init(&attr);
err = pthread_attr_setstacksize(&attr, 32*1024);
if (err) {
    printf("pthread_attr_setstacksize returned non-zero: %s\n",
    strerror(errno));
}
err = pthread_create(&pthThread, &attr, thread, NULL);

pthread_attr_init(&attr);

err = pthread_attr_setstacksize(&attr, 32*1024);

if (err) {

printf("pthread_attr_setstacksize returned non-zero: %s\n",

strerror(errno));

}

err = pthread_create(&pthThread, &attr, thread, NULL);

How to detect which thread suffers from stack overflow? First, you can check your code for recursive function calls and local variables (especially arrays) both of which will be added at runtime to the stack to estimate what should be the stack size. So if you have large arrays you may use a pointer + a call to malloc instead. If this can not fix […]

June 26, 2010March 2, 2017 by Jean-Luc Aufranc (CNXSoft) - No Comments

EP9307 Thin Client with DirectVNC

One of my reader had issues running Thin-clients ENTC Encore-1000 based on EP9307 and wanted to update the firmware in his systems. So I’ll explain how to access Linux, Windows XP or any other operating systems using a thin client based on Cirrus Logic EP9307 hardware. This is for reference only, and the performance may not be suitable for your environment/setup. One PC (server) is needed to run VNC (Virtual Network Computing) server for each remote desktop (i.e. each thin client), then the thin client can run the software without hard disk by just using the network connection. This can be used for checking emails, browsing internet, office applications, etc.. All resource heavy tasks are done on the server side whose specifications may be chosen to match the applications requirements. I’ll explain how to use Linux, but Windows XP (or any other operating systems for that matter) could also be […]

June 19, 2010May 1, 2016 by Jean-Luc Aufranc (CNXSoft) - 2 Comments

Digital Signage Features – A Quick Guide to Select Your Digital Signage Solution

There are a lot of different digital signage solutions around and it may be difficult to find which one is right for you since there can be quite a few different features and options. So I’ll do my best to explain the main features to guide your choice if you are planning to purchase a digital signage solution (embedded signage player, content management software and server). I’ll focus this post on the digital signage player, but bear in mind the content manager software is equally very important. [ad#Google Adsense – Wide Banner] Hardware features Video outputs: composite, component (YPbPr), VGA, DVI, HDMI, LVDS The capability to output simultaneously to different video outputs maybe an advantage if your plan is to use one player to output to several monitors. Video resolution: Standard Definition (e.g. NTSC) vs. High Definition (e.g. 1080p) This is a simple choice based on costs and whether you […]

May 22, 2010September 21, 2010 by Jean-Luc Aufranc (CNXSoft) - 1 Comment

Sigma Designs Android Demo

Here’s a demo of Android running on Sigma Designs SMP8654. They made their own GUI and start Android from there. To see the android part just go to 2:35 directly. Jean-Luc Aufranc (CNXSoft)Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011. www.cnx-software.com

May 8, 2010November 18, 2010 by Jean-Luc Aufranc (CNXSoft) - No Comments

Resources for SMP865x SMP8652 SMP8653 SMP8654 SMP8655 SMP8656

Less than a year ago, Sigma Designs released the SMP8652, a secure media processor “designed to provide the optimal price/performance configuration for thin client applications, which include IPTV set-top boxes, digital media adapters, and hybrid cable/IP thin clients.” SMP8652 provides cost savings compared to the SMP863X series, due the integration of functions such as Ethernet and USB – that allowed them to skip PCI support in their new chip – and better performance (500Mhz MIPS24K CPU). SMP8650 series processors also use the MRUA and DCCHD SDK that need to be purchased as for the previous generation of chips. [ad#Google Adsense – Wide Banner] You can also purchase more SDK from Sigma for SMP8652: Adobe Flash Lite Qt/Webkit Integration Java VM Some DRM SDK (e.g. Microsoft DRM)… As for SMP8630 series, SMP86520 series processors also have a MMU (as most of new chips nowadays) so that you won’t come across the […]

May 2, 2010August 1, 2010 by Jean-Luc Aufranc (CNXSoft) - 2 Comments

Digital Signage Players in Hong Kong and China

I’ll show a few digital signage applications based on Sigma Designs EM8620 and SMP8630 series that are currently used in Hong Kong and China. Bus Digital Signage SinoCDN is a Hong Kong company providing broadband media delivery solutions. SinoCDN currently provides a digital signage solution for Hong Kong – China cross boarder buses called IPAD. Their solution is based on EM8623L Sigma Designs and allows content update thru Wifi at the border between China / Hong Kong. If you’ve ever been at the Hong Kong / China border (Lok Ma Chau) and seen some Wifi access points whose names starts with sinocdn, they are used for this purpose. Digital Signage & POS (Point-of-Sale) Heng Yu Technologies is another Hong Kong company specialized in the manufacturing of “customized input and display technology for the industrial markets” They provide point of sales and advertizing platform based on several Sigma Designs platforms, including […]