Codeigniter 3 and sqlsrv

How can i connect sql server 2008 and code?
i use sqlsrv dll in my php5.4
How can i config my config>database?

SQLSrv Driver Installation could be tricky sometimes but

if you've configured your server environment correctly this should help you:

PHP Code:

$db['mssql'] = array(
    'dsn'    => 'sqlsrv:server=192.168.0.1,1433;Database=xxx',
    'hostname' => '',
    'username' => 'xxx',
    'password' => 'xxx',
    'database' => '',
    'dbdriver' => 'pdo',
    'dbprefix' => '',
    'pconnect' => FALSE,
    'db_debug' => TRUE,
    'cache_on' => FALSE,
    'cachedir' => '',
    'char_set' => 'utf8',
    'dbcollat' => 'utf8_general_ci',
    'swap_pre' => '',
    'autoinit' => TRUE,
    'encrypt' => FALSE,
    'compress' => FALSE,
    'stricton' => FALSE,
    'failover' => array(),
    'save_queries' => TRUE
); 


if you've troubles to install sqlsrv 3.1 or higher you might take a look at this Resource