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What is the basic sequence of data exchange taking place in BIS M-4008?

Data exchange in BIS M-4008

The communication between the controlling system and processor unit is defined by a sequence protocol. Communication between controlling system and processor unit is implemented using a control bit in the output and input buffer.


Basic sequence:

  • The controller sends a command designator to the processor unit in the output buffer with the AV bit set. The AV bit tells the compact processor unit that a job is beginning and the transmitted data is valid.
  • The compact processor unit accepts the job and confirms the job by setting the AA bit in the input buffer.
  • If additional data needs to be exchanged for the job, readiness for additional data exchange is indicated by inverting the TI and TO toggle bits.
  • The compact processor unit has correctly executed the job and sets the AE bit in the input buffer.
  • The controller has accepted all data. The AV bit in the output buffer is reset.
  • The compact processor unit resets all control bits set in the input buffer during the job (AA bit, AE bit). The processor unit is ready for the next job.



All specifications are typical values. Deviations are possible depending on the application and combination of R/W head and data carrier.

The specifications apply to static operation; no CRC_16 data checking.


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