is there another way to connect to a 4 line lcd? to reduce connections

hi,

im using a 4 line lcd for a project using the usual configuration / connection 6 pins.

im just wondering if there is another way to connect to the lcd to reduce the amount of pins, as i need more pins.

Shift registers (1,2 and 3 wire config), I2C and SPI. They all need additional electronics.

I am using 3-wire successfully. You have to make a custom PCB in your home. PCB circuit given here:
http://code.google.com/p/arduinoshiftreglcd/
You can use latest LCD library included in Arduino 1.0.1 from great 'fm' :grin: furthermore, add a good menu in your project and use
http://arduino.cc/forum/index.php/topic,99693.0.html
this will save some more pins...

thanks i found this one looks ideal and frees up 4 pins

thank you

However, i am using 74HC595 Shift register.... :grin:

  1. Use a serial interface: uart, spi, i2c, etc.
  2. Use a shift register: hc164 or hc595. I typically use a 3-wire interface.
  3. Use rc networks to further reduce the number of lines: I think wrote a test piece a while ago reducing it down 1 line. But 2 lines are fairly doable, with no appreciable degradation in speed / performance.

Fit a serial backpack like this one http://www.hobbytronics.co.uk/i2clcd-backpack-v2 and you can reduce the I/O pin count to 1 if you use it as serial RX pin.

thanks for the help, due to cost i intend using a 74HC595 Shift register

just wondering about the lcd library will it work using the standard library?

thanks

Or use a 128x64 graphic lcd that uses the ST7920 controller instead of a character lcd, then you need only 2 pins to control it, and you get nicer text too.

jonisonvespa:
thanks for the help, due to cost i intend using a 74HC595 Shift register

just wondering about the lcd library will it work using the standard library?

thanks

yes