| Online Development Notebook > Index > Programming Overview > Device Commands > Read1WireBit |
Read1WireBit - Read a bit from a 1-wire bus⁄device
VERSION 1.46+ of the firmware, VERSION 58+ of the DLL
Description:
This is a function to send a 1-wire (MicroLAN) bit read on the previously selected port pin.
Command Syntax: (USBm.dll)
USBm_Reset1WireBit( device, dataarray )
The USBm_Reset1WireBit function syntax has these parts:
| Part | Description |
| device | A zero-based index to address the appropriate USB device. |
| dataarray | The function causes this variable to be changed to the value read from the bus (00h for a bit value of 0, and a value that is not 00h for a bit value of 1). Minimum array size of 8 bytes. |
Remarks:
This command does not set the port direction pins or select the pin to use as the 1-wire bus - it is the Reset1Wire command that does this.
VB Declaration
| Public Declare Function USBm_Read1WireBit _ Lib "USBm.dll" _ (ByVal device As Byte, _ ByRef dataarray As Byte)_ As Integer |
VB Example
| Dim dataarray(8) As Byte USBm_Read1WireBit 3, dataarray(0) |
This code fragment addresses U4x1 device #3, and reads a bit from the 1-wire device. The read value is in "dataarray(0)". 00h for a bit value of 0, and a value that is not 00h for a bit value of 1
C Prototype
| int USBm_Read1WireBit ( unsigned char device, unsigned char * data ); |
C Example
| USBm_Read1WireBit ( 3, dataarray ); |
This code fragment addresses U4x1 device #3, and reads a bit from the 1-wire device. The read value is in "dataarray[0]". 00h for a bit value of 0, and a value that is not 00h for a bit value of 1
RobotBASIC
usbm_Read1WireBit(ne_DeviceNumber)
Returns a bit value that is read from the 1wire device.
Raw Command Format:
| Byte Number | Description |
| 0 | 1Fh: Read1WireCmd |
| 1 | <not used> |
| 2 | Byte⁄bit - 0 = write byte, 1 = write bit. Bit feature for VERSION 1.30+ of the firmware |
| 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 is not used.
Byte 2 selects reading either a byte or a bit.
This command does not set the port direction pins or select the pin to use as the 1-wire bus - it is the Reset1Wire command that does this.
Raw Command Response Format:
| Byte Number | Description |
| 0 | 1Fh: Read1WireCmd |
| 1 | Data - Byte⁄bit read. |
| 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 is the byte⁄bit data that was read. Byte 2 through byte 7 are unused.
If a 0 bit is read, data = 0. If a 1 bit is read, data is not 0.
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
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