UASBASP is an efficient programmer for Atmel AVR microcontrollers that works under multiple operating systems including Linux, Mac OS X, and windows. How to assemble this simple programmer read the previous article in this site or go to the original website of Thomas Fischl. As it was mentioned USBasp has two available programming frequencies – high when jumper disconnected and low when connected. These frequencies are 375kHz and 8kHz. To use 375kHz speed, target MCUâ€™s clock frequency has to be at least 1.5MHz – four times higher than SCK. If the target is clocked with low-speed oscillator like 32kHz, then jumper has to be connected as it gives 8kHz SCK which is also 4*8kHz=32kHz.