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Data readout

At READOUT are the FIFOs read by the DSP, formatted and stored in memory. SE_HI is stored temporarily and saved only if the next trigger type indicates a false bhabha. READOUT is generated by LTS when there is a T1YES and a VSAT trigger, or by T2YES if there is a T1YES with no VSAT trigger (a DELPHI event). The logic is shown in figure 4. The data is stored in a DPM to be read from FASTBUS. The DPM is divided into four front end buffers, the current buffer is choosen from the account number stored in SR2.

FIFORESET is issued at T1NO or by T2NO when there is a T2NO with no VSAT trigger. This signal is generated by the LTS and distributed though the auxilliary backplane. On LURFB is this signal ORed with a software generated reset.

The BUSY signal is set by READOUT and reset by the DSP program after the readout has been done. This signal is hardwire ORed on the FASTBUS auxilliary backplane with the BUSY signals from the FDDPs.

Ulf Mjoernmark
Fri Apr 21 14:33:36 METDST 1995