PRELIMINARY
XRT79L71
310
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
This step will cause the internal LAPD Message Buffer pointer to point to the second byte (of Indirect Address
0x01) within the Transmit LAPD Message Buffer.
Sub-STEP 6b.2 - At Address Location 0x11C1 (The LAPD Message Buffer - Indirect Data Register) write
in the value "0x3C" or "0x3E" for the value of SAPI, C/R and EA0.
This step will cause the value "0x3C" or "0x3E" to be written into the location that is being identified by the
LAPD Message Buffer pointer. In this case (per Sub-STEP 6b.1, above) this will be the second byte (of
Indirect Address 0x01) within the Transmit LAPD Message Buffer
STEP 6c - Write the value for TEI and EA1 into the third byte-position, within the Transmit LAPD
Message Buffer
This is accomplished by executing the following two sub-steps.
NOTE: Bellcore mandates that the user use the value of "0x01" for this byte.
Sub-STEP 6c.1 - At Address Location 0x11C0 (The LAPD Message Buffer - Indirect Address Register)
write the value "0x02".
This step will cause the internal LAPD Message Buffer pointer to point to the third byte (of Indirect Address
0x02) within the Transmit LAPD Message Buffer.
Sub-STEP 6c.2 - At Address Location 0x11C1 (The LAPD Message Buffer - Indirect Data Register) write
the value "0x01".
This step will cause the value "0x01" to be written into the location that is being identified by the LAPD
Message Buffer pointer. In this case (per Sub-STEP 6c.1, above) this will be the third byte (of Indirect Address
0x02) within the Transmit LAPD Message Buffer.
STEP 6d - Write in the CONTROL BYTE value of 0x03 into the fourth byte-position, within the Transmit
LAPD Message buffer
This is accomplished by executing the following two sub-steps.
Sub-STEP 6d.1 - At Address Location 0x11C0 (The LAPD Message Buffer - Indirect Address Register)
write the value "0x03".
This step will cause the internal LAPD Message Buffer pointer to point to the fourth byte (of Indirect Address
0x03) within the Transmit LAPD Message Buffer.
Sub-STEP 6d.2 - At Address Location 0x11C1 (The LAPD Message Buffer - Indirect Data Register) write
the value "0x03"
This step will cause the value "0x03" to be written into the location that is being identified by the LAPD
Message Buffer pointer. In this case (per Sub-STEP 6d.1, above) this will be the fourth byte (of Indirect
Address 0x03) within the Transmit LAPD Message Buffer.
STEP 6e - Write in a specific value, which the remote terminal equipment can use to identify the PMDL
Message type.
Therefore, the exact value that the user must write in depends upon the type of LAPD Message being
transmitted to the Remote Terminal Equipment. Table 43 presents a mapping of the value to be written into
this byte, with the corresponding PMDL Message type, to be transmitted.
TABLE 43: A MAPPING OF THE VALUE TO BE WRITTEN INTO INDIRECT ADDRESS LOCATION 0X11B0 AND THE
CORRESPONDING
PMDL MESSAGE
PMDL MESSAGE TYPE
VALUE TO BE WRITTEN INTO ADDRESS LOCATION 0X11B0 (DURING STEP 5E)
Test Signal
0x32
Idle Signal
0x34