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Short Command Format
| Bytes 0 - 1 | Result address to start reading |
| Byte 2 | Number of bytes to read. A value of 0 indicates that 256 bytes should be read. |
Long Command Format
| Bytes 0 - 1 | Result address to start reading |
| Byte 2 - 3 | Number of bytes to read. |
Reply Format
| Bytes 0 - 1 | Result address where reading started |
| Bytes 2 - N | The data bytes read from result structure |
IMAGE (0x10)
Command 0x10 is interpreted by the functional processor as an IMAGE request. This is allowed only in application mode.
There are a number of different ways in which the image buffers may be manipulated. The first byte of the data field is consulted to determine which subcommand is required.
Table 28: IMAGE Subcommands
| Subcommand Index | Function |
| Dark Window | |
| Rectangular Poke | |
| 2+ | Reserved |
Dark Window Subcommand
This subcommand sets a rectangular window in a RAM image buffer to a dark state. The reply is simply an echo of the command. NACK is returned if any of the parameters is out of range.
Command Format
| Byte 0 | Value 0, indicating Dark Window subcommand |
| Byte 1 | Index of image buffer to write to |
| Bytes 2 – 3 | Index of first row of the dark window |
| Bytes 4 - 5 | Index of first column of the dark window |
| Bytes 6 – 7 | Number of rows in the dark window |
| Bytes 8 – 9 | Number of columns in the dark window |
| Bytes 10 – 11 | Dark value 0 |
| Bytes 12 – 13 | Dark value 1 |
| Bytes 14 – 15 | Dark value 2 |
| Bytes 16 – 17 | Dark value 3 |
| Bytes 18 – 19 | Dark value 4 |
| Bytes 20 – 21 | Dark value 5 |
| Bytes 22 – 23 | Dark value 6 |
| Bytes 24 – 25 | Dark value 7 |
Reply Format
| Byte 0 | Value 0, indicating Dark Window subcommand |
| Byte 1 | Index of image buffer to write to |
| Bytes 2 – 3 | Index of first row of the dark window |
| Bytes 4 - 5 | Index of first column of the dark window |
| Bytes 6 – 7 | Number of rows in the dark window |
| Bytes 8 – 9 | Number of columns in the dark window |
| Bytes 10 – 11 | Dark value 0 |
| Bytes 12 – 13 | Dark value 1 |
| Bytes 14 – 15 | Dark value 2 |
| Bytes 16 – 17 | Dark value 3 |
| Bytes 18 – 19 | Dark value 4 |
| Bytes 20 – 21 | Dark value 5 |
| Bytes 22 – 23 | Dark value 6 |
| Bytes 24 – 25 | Dark value 7 |
Rectangular Poke Subcommand
This subcommand allows a rectangular window in a RAM image buffer to be filled in with commanded pixel values. The number of pixels written must be a multiple of the number of pixels in a window row. The number of columns in the window is automatically determined from the number of pixels given.
Command Format
| Byte 0 | Value 1, indicating Rectangular Poke subcommand |
| Byte 1 | Index of image buffer to write to |
| Bytes 2 – 3 | Index of first row of the poke window |
| Bytes 4 - 5 | Index of first column of the poke window |
| Bytes 6 – 7 | Number of pixels in each row |
| Bytes 8 – 9 | First pixel to write |
| Bytes 10 – 11 | Second pixel to write |
| Bytes 11+ | Subsequent pixel data |
Reply Format
| Byte 0 | Value 1, indicating Rectangular Poke subcommand |
| Byte 1 | Index of image buffer to write to |
| Bytes 2 – 3 | Index of first row of the poke window |
| Bytes 4 - 5 | Index of first column of the poke window |
| Bytes 6 – 7 | Number of pixels in each row |
| Bytes 8 – 9 | First pixel to write |
| Bytes 10 – 11 | Second pixel to write |
| Bytes 11+ | Subsequent pixel data |
COMBINATION (0x12)
The combination command may be used by resource constrained host spacecraft to start the star tracker (equivalent to sending a GO command) and then receive result data (equivalent to polling with READ RESULT commands).
Up to half a second may elapse between the command and its replies in normal mode. If a self-test is commanded, tens of seconds may elapse. Be extremely careful using this command if the star tracker shares the NSP bus with other devices.
Table 29: Combination Bitfield
| Bit | Result Offset | Data Length | Name |
| 0x0000 | 0x0004 | Sequence Number | |
| 0x0004 | 0x0004 | Return Code | |
| 0x0008 | 0x0020 | Attitude Quaternion | |
| 0x0028 | 0x0018 | Angular Velocity | |
| 0x0040 | 0x0008 | Epoch time | |
| 0x0048 | 0x0038 | Hardware Telemetry | |
| 0x0080 | 0x00B0 | Statistics Telemetry | |
| 0x0130 | 0x0310 | Image Telemetry | |
| 0x0440 | 0x0068 | ERS Telemetry | |
| 0x04A8 | 0x0340 | Centroid Telemetry | |
| 0x07E8 | 0x0160 | Match Telemetry | |
| 0x0000 | 0x02CC | Built-in Test Result |
Each bit in the bitfield causes a particular piece of data to be returned. Table 27 shows the offset and length into the result structure referenced by each bit.
To run a built-in test, send a Go code consistent with a test, and a bitmap of 0x000800. For normal operation, use a bitmap of 0x0007FF or less.
Command Format
| Bytes 0 | Go code to execute |
| Byte 1 - 3 | Bitmap indicating desired telemetry return |
Date: 2015-12-17; view: 752
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