
SAB 82532/SAF 82532
Detailed Register Description
Semiconductor Group
153
07.96
CSC …
Clear To Send Status Change
Indicates that a state transition has occurred on CTS. The actual
state can be read from STAR register (CTS bit).
Transmit Message Repeat
The transmission of the last frame has to be repeated because
– the ESCC2 has received a negative acknowledgement to an
I-frame in auto-mode, or
– a collision has occurred after at least one FIFO block of data
has been completely transmitted, and thus an automatic
re-transmission cannot be attempted, or
– CTS (transmission enable) has been withdrawn after at least
one FIFO block of data has been transmitted and the frame has
not been completed.
Note: For easier recovery in the case of a collision, XFIFO should
not contain data of more than one frame.
The use of ALLS interrupt is therefore recommended.
Transmit Pool Ready
A data block of up to 32 bytes can be written to the transmit FIFO.
XPR enables the fastest access to XFIFO. It has to be used for
transmission of long frames, back-to-back frames or frames with
shared flags. However, starting transmission of a
new
frame
should be initiated after ALLS interrupt instead of XPR
– in auto mode
– in bus configurations
– if contents of XFIFO have to be unique, e.g. for automatic
repetition of the last frame in case of bus collisions or CTS
control (see also XMR interrupt).
Note: It is not possible to send transparent, or I-frames when a
XMR or XDU interrupt remains unacknowledged.
XMR …
XPR …
HDLC Mode