Many micro-controllers also include embedded PWM. Diolan GPIO-24 adapter supplies PWM mode too. Diolan USB-IO Interface Adapter GPIO-24 adapter provides a solution for adding digital input/output capabilities to user computer with USB port. It allows you to connect different hardware devices to your PC. Easy installation and support makes GPIO-24 adapter the ideal solution to add USB interface to your hardware. GPIO-24http:/ adapter uses PWM technique. The digital PWM (Pulse Width Modulation) is a technique for controlling analog circuits with the digital outputs of the processor. PWM is employed in a wide variety of applications, ranging from measurement and communications to power control and conversion. In PWM mode each contact can be independently configured to send square waves with predefined high and low signal periods. Pulse width modulation is also used to reduce the total power delivered to a load without resulting in loss, which normally occurs when a power source is limited by a resistive element. The underlying principle in the whole process is that the average power delivered is directly proportional to the modulation duty cycle. If the modulation rate is high, it is possible to smooth out the pulse train using passive electronic filters and recover an average analog wave form.