The compilation of Alsa library under embedded Liux

ALSA Basic library called Alsa-lib, and the accompanying test tool is called Alsa-utils, the following describes the Alsa-lib compilation method.

./configure--prefix=/opt/tiny2440/alsa--host=arm-linux--disable-python--disable-old-symbols--with-configdir=/ Etc/alsa--with-alsa-devdir=/dev

./configure--prefix=/opt/tiny2440/alsa--host=arm-linux--disable-python--with-configdir=/etc/alsa- With-alsa-devdir=/dev

1.--with-configdir=dir path where ALSA config files are stored
The default is the prefix directory, which should normally be specified as/etc/alsa because the location on the target Development Board is different.

Note that alsa.conf is placed by default under $prefix/share/alsa/, and if--with-configdir is added, the configuration file is placed there

2.--with-alsa-devdir=dir
Location of the device file, default is/DEV/SND

If you have already compiled it, you can specify an environment variable to change its location:
Alsa_config_dir

Deployment

(1) Check Alsa Drive
Cat/proc/asound/devices
You'll see some devices normally.
0: [0]: Control
[0-0]: Digital audio playback
[0-0]: Digital audio capture
: Timer

(2)/dev/snd
Under normal circumstances, the/DEV/SND has been settled.

Ls/dev/snd
CRW-RW----+ 1 root audio 116, 7 June 1 10:51 controlC0
CRW-RW----+ 1 root audio 116, 6 June 1 10:51 hwc0d0
CRW-RW----+ 1 root audio 116, 5 June 1 10:51 pcmc0d0c
CRW-RW----+ 1 root audio 116, 4 June 1 10:51 pcmc0d0p
CRW-RW----+ 1 root audio 116, 3 June 1 10:51 seq
CRW-RW----+ 1 root audio 116, 2 June 1 10:51 Timer

(3) configuration file
opt/tiny2440/alsa/share/alsa/
Copy the contents of this directory to the/etc/alsa of the Development Board
cp-rf/mnt/alsa/share/alsa/*/etc/alsa/

--------------------------------------------------------------------------------------------------------------- -------------------

"Polar Star friends and relatives positioning": simple and practical, is a suitable for family, friends between the positioning software, real-time query the location of the other side and the map display. Very suitable for family use, less a worry, more than a security guarantee, can promptly know the whereabouts of their families, can avoid finding children, the elderly and other situations.

(In fact, the time, automatic characteristics, can be to a large extent to ensure that families encounter danger when not to drop the chain)

Do not need the other side will use the smartphone, because the software can set the white list automatic response, do not need to do anything to get the other side of the location.
Do not need to open the software reply, also do not need to start the software in advance.

Download location:360 Market (can use 360 mobile phone assistant to download, keyword "Polar Star", "Polar Star friends and relatives positioning")

-As long as the software installed on both sides, and turned on the GPS function (the general mobile phone has been opened), that is, input the other mobile phone number, query location.
-You can select a contact from your address book or select it directly from the recent Contacts menu.
-Whitelist is used to specify trusted contacts, and their query requests are automatically responded to.
-Integrated map display function, if the mobile phone has installed the Baidu map software, you can show the location of each other on the map.
-Can prevent misoperation: Send the button using a delay response design, only after pressing about 1 seconds after the confirmation sent, and the vibration and text prompts you to send success.

--------------------------------------------------------------------------------------------------------------- -------------------