OAD升级，从机可以向主机发出更改连接间隔请求，最小蓝牙间隔更改到20ms就比较快了。修改连接参数是对于image-A.还是image-B程序。我修改了image-A.从机连接参数为20ms，速度提升了，但是在升级过程中会出现 OAD blocks overflow错误，程序如下：
// Minimum connection interval (units of 1.25ms, 80=100ms) if automatic parameter update request is enabled
#define DEFAULT_DESIRED_MIN_CONN_INTERVAL 16//80
// Maximum connection interval (units of 1.25ms, 800=1000ms) if automatic parameter update request is enabled
#define DEFAULT_DESIRED_MAX_CONN_INTERVAL 16//800
// Slave latency to use if automatic parameter update request is enabled
#define DEFAULT_DESIRED_SLAVE_LATENCY 0
// Supervision timeout value (units of 10ms, 1000=10s) if automatic parameter update request is enabled
#define DEFAULT_DESIRED_CONN_TIMEOUT 1000
// Whether to enable automatic parameter update request when a connection is formed
#define DEFAULT_ENABLE_UPDATE_REQUEST FALSE//TRUE
