Online Development Notebook > Index > Programming Overview > Device Commands > InitLCD

InitLCD - Set up the device to use an LCD


Description:

This is a function that initializes LCD variables. This includes the selection of the lines used for RW, RS, E and the port used for data. RW, RS, and E are reset. These commands are appropriate for HD44780 devices and devices that are compatible.

Command Syntax: (USBm.dll)

USBm_InitLCD( device, sel, port )

The USBm_InitLCD function syntax has these parts:

Part Description
device A zero-based index to address the appropriate USB device.
sel Selection of the RW line in the higher nibble, and the RS line in the lower nibble.
port Selection of the LCD data port in the higher nibble, and the E line in the lower nibble. A value of 0-h is port A, a value of 1-h is port B.

Remarks:

Bit⁄Line Selection

Byte Value Result   Byte Value Result
00h Affect A.0   08h Affect B.0
01h Affect A.1   09h Affect B.1
02h Affect A.2   0Ah Affect B.2
03h Affect A.3   0Bh Affect B.3
04h Affect A.4   0Ch Affect B.4
05h Affect A.5   0Dh Affect B.5
06h Affect A.6   0Eh Affect B.6
07h Affect A.7   0Fh Affect B.7

 


VB Declaration

Public Declare Function USBm_InitLCD _
    Lib "USBm.dll" _
        (ByVal device As Byte, _
        ByVal sel As Byte, _
        ByVal port As Byte) _
    As Integer

VB Example

USBm_InitLCD 2, &H89, &H0A

This code fragment will select port A for the data lines to the LCD, B.0 for the RW line, B.1 for the RS line, and B.2 for the E line.


C Prototype

int USBm_InitLCD( unsigned char device, unsigned char sel, unsigned char port );

C Example

 


RobotBASIC

usbm_InitLCD(ne_DeviceNumber,ne_Sel, ne_Port)

Returns true if successfull, false otherwise. It specifies the port to use for the data port and the pins to use for the R⁄W, RS, and E lines for controlling an LCD.


Raw Command  Format:

Byte Number Description
0 10h: InitLCDCmd
1 RW line selection, RS line selection
2 Data port, E line selection
3 <not used>
4 <not used>
5 <not used>
6 <not used>
7 <not used>

Raw Command  Format Details:

Byte 0 contains the command. Byte 1 selects the RW line in the higher nibble, and the RS line in the lower nibble. Byte 2 selects the port to write the byte in the higher nibble, and the E line in the lower nibble. A value of 0-h is port A, a value of 1-h is port B. Byte 3 through byte 7 are unused.

Bit⁄Line Selection

Byte Value Result   Byte Value Result
00h Affect A.0   08h Affect B.0
01h Affect A.1   09h Affect B.1
02h Affect A.2   0Ah Affect B.2
03h Affect A.3   0Bh Affect B.3
04h Affect A.4   0Ch Affect B.4
05h Affect A.5   0Dh Affect B.5
06h Affect A.6   0Eh Affect B.6
07h Affect A.7   0Fh Affect B.7

Raw Command Response Format:

Byte Number Description
0 10h: InitLCDCmd
1 <not used>
2 <not used>
3 <not used>
4 <not used>
5 <not used>
6 <not used>
7 <not used>

Raw Command Response Format Details:

Byte 0 contains the command. Byte 1 through byte 7 are unused.

Raw Command Example Usage:

The command 10-89-0A-00-00-00-00-00 will select port A for the data lines to the LCD, B.0 for the RW line, B.1 for the RS line, and B.2 for the E line.


Hardware:  U401 USB Interface    U421 USB Interface   U451 USB Interface

Programming:  USBm DLL Programming    Download Files

Application Notes:  U4x1 Application Notes    Misc Applications and Information    FAQ

While every effort has been made to make sure that the information posted on this site is correct, the author can not be held liable for any damages whatsoever for losses as a result of the application of this information. Use this information at your own risk.

USBmicro can design your custom and semi-custom USB product. Email about USB design can be directed to " Robert " at usbmicro.com.

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