PEB2085 SIEMENS [Siemens Semiconductor Group], PEB2085 Datasheet - Page 68

• Manufacturer Part Number: PEB2085
• Description: ISDN SubscribernAccess Controller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

2.4.3
In IOM-2 terminal mode (TE mode, SPCR:SPM=0) the microprocessor can access the B and
IC (intercommunication) channels at the IOM-2 interface by reading the B1CR/B2CR or by
reading and writing the C1R/C2R registers. Furthermore it is possible to loop back the
B-channels from/to the S/T interface or to loop back the IC channels from/to the IOM-2
interface without P intervention.
These access and switching functions are selected with the Channel Connect bits (CxC1,
CxC0) in the SPCR register (table 4, figure 34).
External B-channel sources (voice/data modules) connected to the IOM-2 interface can be
disconnected with the IOM off function (ADF1:IOF) in order to not disturb the B-channel access
(see figure 34).
If the B-channel access is used for transferring 64 kbit/s voice/data information directly from
the P port to the ISDN S/T interface, the access can be synchronized to the IOM interface by
means of a synchronous transfer interrupt programmed in the STCR register.
Table 4
C C1
0
0
1
1
Note: x=1 for channel 1 or 2 for channel 2
The general sequence of operations to access the B/IC channels is:
Semiconductor Group
P Access to B/IC Channels (IOM
SIN –
C C0
0
1
0
1
P Access to B and IC Channels
C R
Read
IC
IC
–
B
(set configuration register SPCR)
Program Synchronous Interrupt (ST0)
Read Register (B CR, C R)
(Write register)
Acknowledge SIN (SC0)
C R
Write Read
–
IC
B
B
B CR
B
B
B
–
®
-2)
Output
to
IOM-2
–
IC
B
B
68
Applications
B monitoring, IC monitoring
B monitoring, IC looping from/to IOM-2
B access from/to S
transmission of a constant value in
B channel to S
B looping from S
transmission of a variable pattern in
B channel to S
Functional Description
0
0
0
;
0
;