![](http://datasheet.mmic.net.cn/330000/PEF20321_datasheet_16444041/PEF20321_293.png)
PEB 20321
PEF 20321
Host Memory Organization
Data Sheet
293
2001-02-14
Channel Command:
PCM Core:
LBI:
These bits allow the channel to be initialized, aborted or reconfigured at the serial PCM
side as well as at the
μ
P side.
These bits can be decomposed in 3 independent command groups:
RI, RO, RA form the receive command group
TO, TI, TA
the first transmit command group
and
TH
is the second transmit command group.
In the following section, the functionality of these bits is discussed according to
the groups.
1. Receive Command Group
–
Receive Clear
(not supported by LBI)
RI = 0, RO = 0, RA = 0 (clears a previous receive abort or receive off condition, affects
only the serial interface)
The effect of this command depends on the previous history of the channel
if the channel was never initialized by a receive initialization command it has no
effect
if it was initialized previously it clears a receive off or receive abort condition set by
a previous channel command
if no receive off or receive abort condition is set it has no effect.
–
Fast Receive Abort
(not supported by LBI)
RI = 0, RO = 0, RA = 1 (clears a previous receive abort or receive off condition, affects
only the DMA interface)
This abort is performed in the DMA controller and does not interfere with the reception
on the serial interface and the transfer of the data into the Rx buffer. If this abort is
detected the current Rx descriptor is suspended with an abort status (RA bit set to
‘
1
’
)
followed by a branching to the new descriptor (FRDA) defined in the channel
specification of the CCB.
For HDLC, TMB, TMR the rest of a frame which was only partially transferred before
suspension of the Rx descriptor is aborted, the new descriptor is related to the next
22
RI
21
TI
20
TO
19
TA
18
TH
17
RO
16
RA
22
RI
21
TI
20
0
19
0
18
TH
17
0
16
RA