pwm控制蜂鸣器发出乐音,基于cortex-a8平台，主cpu是s5pc100，开发环境是ubuntu 12.04，linux内核版本是2.6.35-pwm control buzzer tone, cortex-a8-based platform, the main cpu is s5pc100, the development environment is ubuntu 12.04, linux kernel version is 2.6.35