Hi all, my target board is 89S52 @ 5V, 12MHz and I am having Port1 of MCU as dataport of 4x20, HD44780. Whenever I program the MCU using ISP, the LCD is left stranded with Vcc, Gnd and Vcontrast applied. This enables all the pixels of line1 and line3 of LCD(which normally happens).

My doubt is, wont the LCD get affected by this? Also, there is activity on port1 SPI ISP pins during programming, doesnt this affect the LCD? If not now, then on the long run?

I have read that the nematic crystals, if energised using DC, will get degraded in performance. Whenever I program the target board, I am struck with this doubt!

Cheers,
Vignesh