I want to build the AVR High-Voltage programmer, it requires the
RESET pin to source 12 volts while the rest of the AVR is powered by 5 volts. The ground for 12 volts and 5 volts is common.
I know how to switch a led/motor/whatever with a BJT like the 2N2222, but it does not connect in such a way that it can have the same ground as the 5 volts across Vbe.
How to switch 12 volts using the same GND as the 5 volts doing the Vbe switching?
Context - From page 167 (19.7.1) of the datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/doc8006.pdf
Enter High-voltage Serial Programming Mode
- Set ... RESET pin and VCC to 0V.
- Apply 4.5 - 5.5V between VCC and GND. Ensure that VCC reaches at least 1.8V within the next 20 µs.
- Wait 20 - 60 µs, and apply 11.5 - 12.5V to RESET.
- Exit Programming mode by power the device down or by bringing RESET pin to 0V.