Within the Raw data buffers, data are organized in the following way:
|
$0000: | FADC 0 - strip 0 | FADC 1 - strip 0 |
| $0004: | FADC 2 - strip 0 | FADC 3 - strip 0 |
| $0008: | FADC 4 - strip 0 | FADC 5 - strip 0 |
| $000C: | FADC 6 - strip 0 | FADC 7 - strip 0 |
| $0010: | FADC 0 - strip 1 | FADC 1 - strip 1 |
| . | ||
| . | ||
| . | ||
i.e. for every strip number there is a block of 8 16-bit words for all connected FADCs. Note the change compared to previous (OnSiRoC) raw data !!
Apart from the first three bits being no longer 1 but 0, the format of the individual 32-bit raw data word has not changed:
000DDDDD'DDDDDDDD'000DDDDD'DDDDDDDD
In case of Raw data readout, the PPC takes 2048 16-bit data words per FADC (stems from the times of OnSiRoC readout) which amounts to 8192 long words per PPC.
When unpacking one needs to know the mask of selected PPC boards which is contained within the SIRS bank (s. App.A.1).
A safe way to decide whether a given SIFE bank contains PPC formatted or unformatted data is to check the upper bits of the halfwords (see sec. 1.5.2).