These 14 pin modules are probably Hitachi compatible LCD displays (they nearly all are). They can be interfaced by only 4 data lines and 3 control lines. I attach a pin out and information from our C Compiler's help file. The full help file which includes a sample circuit for interfacing to the modules can be downloaded with the demo of the C Compiler from our web site (below). However you really need the data sheet for full details (which is far too big to post even if I had it in magnetic form) . I only have a hard copy I'm afraid, you could try the Hitachi web site, or the manufacturer of your module. These are quite nice modules, low power supply, easy to drive and don't use much I/O on the PIC - the 4 data lines can be used for other functions when you're not driving the module. Only problem is that they are so slow that you may wish to drive them on an interrupt or sampling loop - some operations take milli-seconds ! Robin Abbott - robin.abbott@dial.pipex.com ************************************************************************** * * Forest Electronic Developments * http://dspace.dial.pipex.com/robin.abbott/FED * ************************************************************************** ----- Original Message ----- From: Chaipi Wijnbergen To: Sent: 03 October 1999 14:19 Subject: 14 pin LCD modules > Hello, > > I have two types of LCD modules, each is 14 pin, 2 lines of 16 characters. Extract from FED PIC C help file ========================= Functions are provided to drive an LCD module based on the Hitachi chip set. The functions handle the 4 bit interface, and the device timing to the module. They also read the module busy flag and hold future transfers whilst the module is still performing the last operation. Functions are provided to initialise the module, to transfer single characters to the module, to transfer LCD module commands, and to write strings to the module. Such modules are the LM020, LM016, LM018 and LM032, however there are a number of other modules based on this chip which is numbered HD44780. The module is driven from port B, there is no option to change the default port. The pin connections are as follows: LCD Module, Pin Number on port, (2 line display - LM016L - pin number) RS B1 4 R/W B2 5 E B3 6 D4 B4 11 D5 B5 12 D6 B6 13 D7 B7 14 Vss - 1 Vdd - 2 Vo (LCD Supply) - 3 Connections D0, D1, D2 and D3 on the module can be left floating. The LCD display has an 8 bit interface, but read and write operations are executed in two 4 bit transfers. For ports which do not have pull up resistors the D4 to D7 signals should be pulled up to +5V with 10k-100K resistors. Bits 0 to 3 of the LCD should be left floating, or tied high. Port bit 0 on the LCD port is still available for general use, in this case the tris-state command for the LCD port should be set to drive on bits 2 , 3 and 4, and to read on bits 4, 5, 6, and 7. Bits D4 to D7 are available for general purpose inputs when the module is not being used, but in this case should be coupled with resistors to allow the main program to overdrive the inputs when the module is being written. The functions used to drive the module are LCD and LCDString. The LCD function takes one parameter. This has different values depending on the function as described below. The LCDString function writes a complete string to the display.