PEB2080 SIEMENS [Siemens Semiconductor Group], PEB2080 Datasheet - Page 21

• Manufacturer Part Number: PEB2080
• Description: S/T Bus Interface Circuit(SBC)
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

The basic frame consists of a total of 32 bits, or four octets: B1 + B2 + D (18 bits) plus 14 bits of
MONITOR and control information. The data in both directions are synchronous and in phase
(figure 8).
Figure 8
IOM
1st octet B1:
2nd octet B2
3rd octet:
4th octet B*:
The C/l channel is used for communication between the SBC and a processor via a layer-2 device,
to control and MONITOR layer-1 functions. The codes originating from layer-2 devices are called
“commands”, those sent by the SBC are called “indications”. For a list of the C/l codes and their use,
refer to chapter 4.
Three modes of the lOM are distinguished. These modes differ only with respect to the physical data
rate (256 or 8 x 256 kbit/s) and to polarity of the clocks.
Semiconductor Group
®
Interface Frame Structure
B channel (64 kbit/s), most significant bit first
MONITOR channel (64 kbit/s) -”-
2-bit D channel (16 kbit/s)
4-bit C/I channel
T channel: not used with SBC
E bit: not used with SBC.
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Functional Description