how to wire LCD with SPI

CrossRoads:
With SPI, pins 13-12-11 are connected to all devices. Unique Slave Select pins are used to enable one device at a time.

If you are using a ST7920-based graphic LCD, then unfortunately it does not have a CS input. This means that it cannot share the SPI pins with another device. Here are a few solutions:

  1. Drive one of the devices using software SPI. The ST7920 can be drive using ShiftOut, although ShiftOut is unnecessarily slow, and it'e easy to write a faster version.

  2. If you are not using the UART, you can use the UART in SPI mode to get a second SPI channel.

  3. Use an external and-gate to gate the clock to the ST7920.

However, if it's a text LCD (which uses about 5 other pins as well), then you can use any pins you like for RS and RW.