The SMuRF packet is formed by a header and a payload:
The header is 128-byte long and contains the following information:
| Starting word | Offset [byte] | Length [bytes] | Function | Description |
|---|---|---|---|---|
| 0 | 0 | 1 | Protocol version | Number to describe protocol version. 0x01 to start |
| 1 | 1 | ATCA crate | Crate number starting from 1 (0 reserved for testing) | |
| 2 | 1 | ATCA card | Slot Number starting from 1 (0 reserved for testing). | |
| 3 | 1 | Smurf timing Configuration | (clock lock / unlock), (external ref, fiber timing ref) | |
| 4 | 4 | Number of channels of data | 32 bit word giving number channels of following data | |
| 1 | 8 | 40 | TES DAC 0-15 | TES DAC values. 16X 20 bit in 10X32 bit words, or 5X 65 bit |
| 6 | 48 | 8 | 64-bit epoch UNIX time | 64-bit UNIX epoch time, in nanoseconds |
| 7 | 56 | 4 | Flux ramp increment | signed 32 bit integer for increment |
| 60 | 4 | Flux ramp offset | signed 32 it integer for offset | |
| 8 | 64 | 4 | Counter 0, since last 1Hz marker | 32 bit counter since last 1Hz marker |
| 68 | 4 | Counter 1, since last external input | 32 bit counter since last external input | |
| 72 | 8 | Counter 2, 64 bit timing system counter | 64 bit timestamp | |
| 10 | 80 | 4 | Averaging reset bits | up to 32 bits of average reset from timing system |
| 84 | 4 | Frame counter | Locally genreate frame counter 32 bit | |
| 11 | 88 | 4 | TES relay settings | TES and flux ramp relays, 17bits in use now |
| 12 | 96 | 5 | External real time clock from timing system | Syncword from mce for mce based systems (40 bit including header) |
| 13 | 104 | 1 | Control field | SEE TABLE BELOW WITH BIT DESCRIPTIONS... |
| 105 | 1 | Test parameters | ||
| 14 | 112 | 2 | Number of rows | MCE header value (max 255) (defaluts to 33 if 0) |
| 114 | 2 | Number of rows reported | MCE header value (defaults to numb rows if 0) | |
| 15 | 120 | 2 | Row length | MCE header value |
| 122 | 2 | Data rate | MCE header value |
The bits in the control filed (byte offset 104) are:
| bit | Description |
|---|---|
| 0 | Clear average and unwrap |
| 1 | Disable stream to MCE |
| 2 | Disable file write |
| 3 | Set to read configuration file each cycle |
| 4-7 | Test mode: 0=normal, 1-15=test modes (see below) |
The test mode selected by bits 4-7 are
| Mode | Description |
|---|---|
| 0 | normal data |
| 1 | All zeros for smurf data |
| 2 | Smurf channels value = channel # |
| 3 | smurf data channels toggle between -20000, and 20000 on syncword = multiple of 1000 |
| 4 | Each smurf channel independantly uniformly spaced random numbers, peak to peak 1000 (before filter) |
| 5 | Sine waves, frequency = (param+1) * flux_ramp_rate / 2^16 |
| 6 | |
| 7 | |
| 8 | MCE output data all set to zero |
| 9 | MCE output data = mce channel number |
| 10 | MCE output ramps with syncbox signal * param |
| 11 | |
| 12 | |
| 13 | |
| 14 | Break checksum on 1/1000 mce frames |
| 15 | Force framedrops on 1/1000 mcde frames |
The payload contains signed 32-bit averaged data points. The number of points is defined in the header's Number of channels of data word.