PSB2186 Datasheet, PDF (73/240 Pages) Siemens Semiconductor Group – ISDN Subscriber Access Controller for Terminals

Functional Description
The termination of the transmission operation may be indicated either with:
– XPR interrupt, if a positive acknowledgement has been received,
– XMR interrupt, if a negative acknowledgement has been received, i.e. the transmitted
message must be repeated (XMR = Transmit Message Repeat),
– TIN interrupt, if no acknowledgement has been received at all after N2 times the expiration
of the time period t1 (TIN = Timer INterrupt, XPR interrupt is issued additionally).
Note: Prerequisite for sending I frames in the auto-mode (XIF) is that the internal operational
mode of the timer has been selected in the MODE register (TMD bit = 1).
The transparent transmission of frames (XTF command) is possible in all message transfer
modes. The successful termination of a transparent transmission is indicated by an XPR
interrupt.
In all cases, collisions which occur on the S-Bus (D channel) before the first XFIFO pool has
been completely transmitted and released are treated without µP interaction. The ISAC-S TE
will retransmit the frame automatically.
If a collision is detected after the first pool has been released, the ISAC-S TE aborts the frame
and requests the processor to repeat the frame with an XMR interrupt.
Semiconductor Group
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