Vermes
Advanced Member level 4
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
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