WriteA

Write byte value to port A

Description:

This is a function that writes a byte value to port A when the port is set as an output. The possible values range from 0-255 (00h to FFh).

Command Syntax: (USBm.dll)

USBm_WriteA( device, data )

The USBm_WriteA function syntax has these parts:

Part	Description
device	A zero-based index to address the appropriate USB device.
data	Byte to write to Port A.

Remarks:

Port A does not have to have all 8 bits set to output for this to work. You can have a mix of inputs and outputs on the port and this command will set high or low only those lines that are output.

VB Declaration

Public Declare Function USBm_WriteA _
    Lib “USBm.dll” _
        (ByVal device As Byte, _
        ByVal data As Byte) _
    As Integer

VB Example

USBm_WriteA 3, &H55

This code fragment writes the value of &H55 to port A of device 3.

C Prototype

int USBm_WriteA( unsigned char device, unsigned char data );

C Example

RobotBASIC

usbm_WriteA(ne_DeviceNumber,ne_ByteValue)

Returns true if successful, false otherwise. The byte value is written to Port A⁄B.

Raw Command Format:

Byte Number	Description
0	01h: WriteACmd
1	Byte Data – This byte is written to port A, D0 – D7 The most significant bit of the byte value is written to D7
2	<not used>
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 contains the data to write to port A. Byte 2 through byte 7 are unused.

Raw Command Response Format:

Byte Number	Description
0	01h: WriteACmd
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:

Writing an E7h to port A with the command 01-E7-00-00-00-00-00-00 will set A.7, A.6, A.5, A.2, A.1, and A.0 high and will set lines A.4 and A.3 low, assuming that they are configured as outputs.