PEB2085 SIEMENS [Siemens Semiconductor Group], PEB2085 Datasheet - Page 212

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

4.1.14
SAPI1
CRI
4.1.15
Value after reset: undefined
RDA
RDO
Semiconductor Group
7
SAPI1 Value
Value of the first programmable Service Access Point Identifier (SAPI) according to
the ISDN LAPD protocol.
Command/Response Interpretation
CRI defines the end of the ISDN user-network interface the ISAC-S is used on, for
the correct identification of "Command" and "Response" frames. Depending on the
value of CRI the C/R-bit will be interpreted by the ISAC-S, when receiving frames in
auto-mode, as follows:
For transmitting frames in auto-mode, the C/R-bit manipulation will also be done
automatically, depending on the value of the CRI-bit (refer to XAD1 register
description).
In message transfer modes with SAPI address recognition the first received address
byte is compared with the programmable values in SAP1, SAP2 and the fixed group
SAPI.
In 1-byte address mode, the CRI-bit is to be set to "0".
7
Receive Data
A "1" indicates that data is available in the RFIFO. After an RME interrupt, a "0" in this
bit means that data is available in the internal registers RHCR or SAPR only (e.g.
S-frame). See also RHCR register description table.
Receive Data Overflow
At least one byte of the frame has been lost, because it could not be stored in RFIFO
(1).
SAPI1 Register
Receive Status Register
Command
0
1
RDA
RDO
CRC
SAPI1
Receiving End
subscriber
network
RAB
212
SA1
SAP1
RSTA
C/R Bit
Command
1
0
SA0
Write
Read
CRI
C/R
Register Description
TA
Response
0
1
0
Address 26
Address 27
0
0
H
H