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PEB 20321
PEF 20321
Host Memory Organization
Data Sheet
296
2001-02-14
4. Before changing the MODE, CRC, CS, TRV, INV, TFLAG bits of a channel or its RTI
or time slot assignment or its fill/mask bits it should have been shut down. The bits
should be changed while issuing the receive off command.
5. To revive a channel after it has been shut down, the receive initialization command
should be used.
6. To switch to a new starting point of a Rx descriptor chain one should preferably use
the receive jump command, only exceptionally the fast receive abort command and
never the receive initialize command.
7. To issue channel commands not affecting the receive side one should issue
–
a receive clear command if neither a receive off nor a receive abort condition is set
–
a receive off command if a receive off condition is set
–
a receive abort command if a receive abort condition is set.
8. Combinations of the bits RI, RO, RA not in this description are reserved and are not
allowed to be used.
2. First Transmit Command Group
–
Transmit Clear
(not supported by LBI)
TI =
‘
0
’
, TO =
‘
0
’
, TA =
‘
0
’
(clears a previous transmit abort or transmit off condition,
affects only the serial interface)
if the channel was never initialized by a transmit initialization command it has no
effect
if it was initialized previously it clears a transmit off or transmit abort condition set by
a previous channel command
if no transmit off or transmit abort condition is set it has no effect
–
Fast Transmit Abort
(not supported by LBI)
TI =
‘
0
’
, TO =
‘
0
’
, TA =
‘
1
’
(clears a previous transmit abort or transmit off condition,
affects only the DMA interface)
This abort is performed in the DMA controller and does not interfere with the current
transmission on the serial interface and the transfer between the TF and TB. If this
abort is detected the current descriptor is suspended and the frame or data transferred
to the TB is aborted. The next frame beginning in the Tx descriptor (FTDA) defined in
the channel specification of the CCB will be started immediately.
For HDLC, TMB, TMR the first part of the frame of the suspended descriptor is sent
and append by
011 1111 1111 1111 for HDLC
at least
00
H
for TMB
at least
00 00
H
for TMR
Afterwards the next frame is started.
For V.110/X.30 three 10-octet frames with errors in the synchronization pattern are
sent after the data of the suspended descriptor, afterwards the next data are sent in
correct frames.
For TMA a TFLAG (FA =
‘
1
’
) or FF
H
(FA =
‘
0
’
) is sent in at least one time slot after the
data of the suspended descriptor, afterwards the next data are sent.