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PEB 20321
PEF 20321
Host Memory Organization
Data Sheet
295
2001-02-14
For TMB: a currently processed frame is aborted after
≤
15 received bits for this
channel, leading to an interrupt with FI set but ERR on 0, the status of this frame is
always 00
H
.
For TMR: a currently processed frame is aborted after
≤
31 received bits for this
channel, leading to an interrupt with FI set but ERR on 0, the status of this frame is
always 00
H
.
Note 1: It is recommended to clear the receive abort condition via a receive off
command for V.110/X.30 mode, the TMB and the TMR mode.
Note 2: After issuing a receive abort channel command it is advisable to stay in this
condition during at least 16, 240, 16, 32, 8 bits of the channel for HDLC, V.110/
X.30, TMB, TMR, TMA respectively.
–
Receive Jump
RI =
‘
1
’
, RO =
‘
0
’
, RA =
‘
0
’
(clears a previous receive abort or receive off condition,
affects only the DMA interface)
During normal operation branching to a new descriptor (FRDA) is possible without
interrupting the current descriptor and aborting the received frame (HDLC, TMB,
TMR) or received data (V.110/X.30, TMA).
The DMA controller will proceed finishing the current receive descriptor as usual either
with a frame end condition or with the corresponding data buffer completely filled and
afterwards branch to the new descriptor specified by FRDA. Thus a received frame
may be splitted on
‘
old
’
and
‘
new
’
descriptors.
–
Receive Initialization
RI =
‘
1
’
, RO =
‘
0
’
, RA =
‘
1
’
(clears a previous receive abort or receive off condition,
affects the DMA and serial interface)
Before the MUNICH32X has got a receive initialization command it will not receive
anything properly in a channel. This command should therefore be the first channel
command after a reset for a channel to be used. FRDA is then the address of the
starting point of the Rx descriptor chaining list.
If the command is issued during normal operation it only affects the DMA interface.
The current Rx descriptor is suspended without writing the second DWORD with the
status, no interrupt is generated. For HDLC, TMB, TMR the rest of a frame which was
only partially transferred before the suspension of the Rx descriptor is aborted, the
new descriptor (FRDA) is related to the next frame.
For V.110/X.30 and TMA data bits might get lost.
General Notes on Receive Commands:
1. After a pulse at the reset pin a channel having a time slot with RTI =
‘
0
’
should be
issued receive off commands until it is used.
2. When the channel is intended to be used, a receive initialize command should be
issued before using any other receive channel command.
3. To shut down a channel in receive direction, it should first be set into the receive abort
condition for the time specified there and then set into the receive off condition.