SAB82538 Datasheet, PDF (123/253 Pages) Infineon Technologies AG – ICs for Communications

SAB 82538
SAF 82538
HDLC Mode
– 2-byte address field (MODE.ADM = 1)
XAD1 constitutes the high byte of the 2-byte address field. Bit 1 must be set to 0.
According to the ISDN LAPD protocol, bit 1 is interpreted as the C/R (COMMAND/
RESPONSE) bit. This bit is manipulated automatically by the ESCC8 according to the
setting of the CRI bit in RAH1:
Bit 1
(C/R)
Commands transmit
1
0
Response transmit
0
1
CRI = 1
CRI = 0
(In ISDN LAP-D, the high address byte is known as SAPI).
In accordance with the HDLC protocol, bit 0 should be set to 0, to indicate that the
address field contains (at least) one more byte.
– 1-byte address field (MODE.ADM = 0)
According to the X.25 LAPB protocol, XAD1 is the address of a COMMAND frame.
Transmit Address Byte 2 (READ/WRITE)
7
2-byte address
XAD2
XAD2 (low byte)
1-byte address
XAD2
XAD2 (RESPONSE)
0
(offset: 25)
Second individually programmable address byte.
– 2-byte address (MODE.ADM = 1)
XAD2 constitutes the low byte of the 2 byte address field
(In ISDN LAP-D, the low address byte is known as TEI).
– 1-byte address (MODE.ADM = 0)
According to the X.25 LAPB protocol, XAD2 is the address of a RESPONSE frame.
Note: XAD1, XAD2 registers are used only if the ESCC8 is operated in auto-mode.
Semiconductor Group
123