Difference between revisions of "Spi lcd 1.2 protocol"
(Created page with 'To display a string on the LCD, just send over SPI the same bytes you would send to LCD, prefixed with the address of the LCD (the default address is 0x82). Bytes above 0xf0 ar…')
Revision as of 11:43, 14 February 2012
To display a string on the LCD, just send over SPI the same bytes you would send to LCD, prefixed with the address of the LCD (the default address is 0x82).
Bytes above 0xf0 are "special".
0xf0 <xy> is set cursor. the <xy> byte is 3 bit line number and 5 bit position number. This addressing allows up to 8 lines of 32 characters.
0xf1 is clear LCD.
0xf2 <addr> is "set address". If you want to change the address the module reacts to. The address is stored in eeprom, and will remain this way after a powercycle.
0xf3 <contrast> is "set contrast". This will set the contrast to the value you specify. 0x40 is the default that works fine for the LCDs that we have.
0xf4 <backlight> is the "set backlight intensity" command. This will set the backlight intensity to the value specified.
0xf5 <byte> will send the byte as a command to the HD44780. You need this for example to use the user-defined characters.
0xff <byte> will send the byte to the LCD without special character processing. This allows you to send codes 0xf0 through 0xff to the LCD if required.
Other bytes are reserved and are currently implemented as a no-op.