Which one of these modes is the best for get noise immunity when driving a LCD Display 16x02? (or 16x04 etc.)
-I2C module using PCF8574 I/O expansion.
-8 bit Parallel
-4 bit Parallel
I had a PCB which drives an LCD Display 16x02 and drives 4 dc motors (80mA each - no load). When a used to use this pcb I got some problems with noise from the motors and sometimes I got strange characters printed by LCD. I used to use Parallel 4 bit mode. But now I'm designing a new PCB which will drive 4 motors with H-Bridge and 1 LCD Display 16x02 and will have 2 UART and 1 I2C communications using a PIC16F1947 MCU.
I'm going to be sure for have a great ground plane on my PCB (4 layers) and I'm going to increase noise protection too.
Should I still using 4 bit Parallel mode and do something to decrease the noise? Should I change for 8 bit Parallel mode? or Doesn't it make sense? Should I change to use I2C module? I know I2C is for communications between ICs in the same PCB but I think Could be better because 2 wires is less than 8 wires so Could be more difficult to get noise using i2c mode.
The distance between the pcb and the LCD Display is like 20 cm. Should I do somethings on the cables? Like Twist the cables?
I think could be good for all of us know the safest way to drive an LCD Display.
Sorry for my bad English.