During my project I am going to make the PCB design, but before this I would like to ask you one simple question.
I am using the ATMega2560 at 5V Vcc. In my circuit the AVR SPI Port is simultaneously connected to :
- a series of CD74HC595 shift registers (5V Vcc)
- the ISP header (I am using the JTAG ICE mk2 and DRAGON)
- an SPI 3V3 exterbal flash (3.3V Vcc)
As you can see at the photos, there is a level shifting circuitry between the uC and the memory.
Will this circuitry have any negative effect to the ISP functionality ?
Any opinion is wellcome.
Thank you in advance.