IPU Data Channel

Data Format

The request to start readout of the data of a specific event is the same as the trigger information delivered on the LVL1 trigger channel - a single TRM packet aka a short transfer:

Positions in the network packet are as follows:
Bits Content
47 - 40 Additional Information
39 - 32 Random Data
31 - 16 16 bit counter
3 - 0 Type

Word 15-12 11-8 7-4 3-0
F0 reserved (CRC)
F1 add. information random code
F2 trigger number
F3 0 seq. no. type

The type and additional information are not yet defined and set to 0.

Application Interface

The ipudata-Entity provides an interface to the internal logic to handle all readout requests.

Name Width Description
IPU_TRG_NUMBER_OUT 16 Number of the Event to be read out
IPU_READOUT_OUT 1 data on trb_number is valid during high. Is raised after request is received and reset after readout_finished
IPU_DATA_IN 32 Data input for event data
IPU_DATAREADY_IN 1 Datavalid strobe for data_in (offered data is accepted, when read is high in the same clock cycle)
IPU_READ_OUT 1 Interface is able to accept data
IPU_READOUT_FINISHED_IN 1 End of transfer by application
IPU_LENGTH_IN 16 The length of the upcoming data transfer.
IPU_ERROR_PATTERN_IN 32 Errorbits generated by application.

  • The trigger random code is transfered with the request packet, but is not offered to the application - otherwise its function as additional security is lost. All entities despite the application are then able to check the code, but the application is forced to save the code as a proof of authenticity.

  • The read signal will be low for one clock cycle after each dataready due to the conversion from 32 to 16 bit word size.

  • Length must be valid during the first dataready signal, error pattern must be valid while readout_finished is high

  • Readout of an Event containing three data words on an IPU channel endpoint:
    Readout of an Event containing three data words on an IPU channel endpoint
I Attachment Action Size Date Who Comment
ipu_timing_diagram.pngpng ipu_timing_diagram.png manage 20 K 2009-05-28 - 15:17 JanMichel Readout of an Event containing three data words on an IPU channel endpoint
Topic revision: r4 - 2009-05-28, JanMichel
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