PEB 2091
PEF 2091
Functional Description
DU
DD
1
1
BAC
S/G
TBA2
A/B
TBA1
1
TBA0
1
1
1
1
1
E
E
S/G-bit
(Stop/Go), available to a connected HDLC controller to determine if
it can access the D-channel (S/G = 1: stop, S/G = 0: go).
A/B-bit
(available/blocked), supplementary bit for D-channel control.
(A/B = 1: D-channel available, A/B = 0: D-channel blocked).
TBA0-2:
TIC Bus Address
3.6.2
IOM®-2 Command / Indication Channels
The Command/Indication channels carry real-time control and status information over
the IOM®-2 interface.
3.6.2.1 Active C/I Channel
The active C/I Channel of the IEC-Q is available in all operational modes. The channel
consists of four bits in each direction. Activation and deactivation of the IEC-Q is always
controlled via the active C/I Channel. The C/I codes going to the IEC-Q are called
’commands’, those originating from it are referred to as ’indications’.
The IEC-Q verifies C/I commands with a double last-look criterion, i.e. a new command
will be recognized as valid only after it has been correctly detected by the IEC-Q for two
consecutive IOM®-2 frames.
If the microprocessor interface is not being used for controlling the C/I Channel,
commands have to be applied continuously on DIN until the command is validated by the
IEC-Q and the desired action has been initiated. Afterwards the command may be
changed which would initiate another action by the IEC-Q. An indication is issued
permanently by the IEC-Q on DOUT until a new indication needs to be forwarded.
In stand-alone mode the active C/I Channel is controlled by an external device, e.g. the
ICC, 3PAC, IPAC or ISAR, EPIC®, ELIC®.
In µP mode the active C/I Channel can either be controlled by an external device or via
the microprocessor interface. For a description on how to access the active C/I Channel
via the µP-interface please refer to chapter "Microprocessor Access to IOM®-2
Channels", page 97.
All available C/I codes of the IEC-Q are listed and explained in "C/I Channel Codes",
page 224.
Semiconductor Group
75
Data Sheet 01.99
INFINEON [ Infineon ]
