| Online Development Notebook > Index > ODN > Raw Device Programming > 0B - StrobeWriteCmd |
Command #0B - StrobeWriteCmd
Description:
Strobe write of a byte value to a port. This command selects port A or B for the written byte, as well as a polarity (negative or positive) and a line (A.0 - B.7) to toggle. The byte is written and then the line toggled.
Command Format:
| Byte Number | Description |
| 0 | 0Bh: StrobeWriteCmd |
| 1 | Byte data to write |
| 2 | Port to write data |
| 3 | Negative⁄Positive strobe selection and strobe line selection |
| 4 | Strobe pulse length VERSION 1.34+ of the firmware |
| 5 | <not used> |
| 6 | <not used> |
| 7 | <not used> |
Command Format Details:
Byte 0 contains the command. Byte 1 is the data to write. Byte 2 indicates the port to write the byte. A value of 00h is port A, a value of 01h is port B.
Byte 3 contains the strobe direction and the strobe line selection.
Byte 4 contains a delay to lengthen the strobe. Valid values from 00h - FFh (0 - 255).
Byte 5 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 |
With Byte 3 set to the Bit⁄Line Selection values, the strobe is negative-going. By adding 10h to this value, the strobe will be positive-going. For example: 18h would pulse B.0 from low to high, and back low.
Response Format:
| Byte Number | Description |
| 0 | 0Bh: StrobeWriteCmd |
| 1 | <not used> |
| 2 | <not used> |
| 3 | <not used> |
| 4 | <not used> |
| 5 | <not used> |
| 6 | <not used> |
| 7 | <not used> |
Response Format Details:
Byte 0 contains the command. Byte 1 through byte 7 are unused.
Example Usage:
If a device is connected to the U4xx that will accept a byte of data from port A when B.7 is toggled from high to low and back to high, then the following commands would write 55h to this device.
First set the B.7 line high with a SetBitCmd command: 07-0F-00-00-00-00-00-00 The line is set high to begin with because the strobe commands do not initialize the state or direction of the line. (B.7 needs to be set as an output.)
Then write to port A and toggle B.7 low, then high. 0B-55-00-0F-00-00-00-00 The breakdown of the first four bytes of the command is: 0Bh - StrobeWriteCmd, 55h - data to write, 00h - port to write (A), 0Fh - line to toggle (-F) and toggle direction (0-).
Changing to a positive strobe would necessitate changing the initial line value, and substituting 1Fh for the fourth byte.
| Hardware: U401 USB Interface U421 USB Interface |
| Programming: USBm DLL Programming Download Files |
| Application Notes: U4x1 Application Notes Misc Applications and Information FAQ |