Few lcd questions

Hi everyone. As it's a fact that digital pins of Arduino do not provide analog output, but switches so fast that we assume it's giving output between 0 & 255. (true?)

  1. In that case would it be good enough to use pwm voltages for lcd's backlight?
  2. I've LMB162abc & following a tutorial hacktronics I've made it work but I've used 4 bits only (text + both rows are working), what are the other 4 bits for? As it is an eight bit lcd then there might be some difference.
  • Indeed you can vary the backlight (LED) brightness using PWM. That said, you really only ever need three levels - bright (day), dim (night) and off, and usually only two of them, so a resistor works just fine.

  • No idea what a LMB162abc is.

Paul__B: - Indeed you can vary the backlight (LED) brightness using PWM. That said, you really only ever need three levels - bright (day), dim (night) and off, and usually only two of them, so a resistor works just fine.

  • No idea what a LMB162abc is.

Thanks a lot sir :)

LMB162abc is 16 pin lcd like other common lcds for arduino, working procedure & libraries are same that are available online for other 16pin lcds, it has 8 data lines & supports either 8bit or 4bit. Where as 4 bit is working really fine then I'm curious what can be the difference between 8bit mode & 4bit mode, data sheet also doesn't make this thing clear.

Edit: Got it from this thread =>http://forum.arduino.cc/index.php?topic=125347.0 4 bit vs 8 bit, only a minimal speed difference practically of no use :)

The difference is that 8-bit mode uses 4 extra pins. It is no better, faster, cooler, ... than 4-bit mode.

When the HD44780 controller first appeared, it was common to connect it to an external address and data bus. Very few products do this now. In this mode, you need all 8 data pins and you also need address decoding and control of RW, RS, E pins.

David.

Thanks a lot David Sir, now it's clear :)