USBASP-OPTO-MONSTER – version with extras

[Vermes]

It is an improved version of USBASP programmer.
Features:

• full optical isolation of ISP signals
• when switching power – then GND and VCC can be connected to an external system
• securing the power output from the connector Kanda by a polymer PTC fuse 200mA
• the circuit has independently derived supply +3,3V. It sometimes is needed while making a prototype on a contact board. When a processor is powered by +5V and some peripherals require separate 3,3V. Efficiency 0,8A (LM1117-3.3)
• special protection against the suspension of the processor in the programmer was derived, when after connecting the supply to an external system suddenly a large current flows. The protection is on the schema: D3 diode and C4 tantal capacitor. Besides, it is still C7 SMD tantal 100uF at the switch of the output voltage type at the ISP
• a clear control of the attached voltage level +3,3V or +5V. LED backlighting was used on which there is a print on transparent film

Green diode in the middle in the button is one of USBASP diodes – indicating right operating after running. Red diode on the left lights while programming.
Scheme:



And some pictures:



Comparison to the dimensions of an old USBASP:



Link to original thread (useful attachment) – USBASP-OPTO-MONSTER - kolejna wersja z EXTRAsami