peb20560 Infineon Technologies Corporation, peb20560 Datasheet - Page 66

• Manufacturer Part Number: peb20560
• Description: Dsp Oriented Pbx Controller Doc
• Manufacturer: Infineon Technologies Corporation

Semiconductor Group
When the group controller wants the SACCO to re-transmit a frame (e.g. due to a
CRC-error) it does not answer with a RR-acknowledge but emits a second RR-poll.
The SACCO then generates an XMR-interrupt (transmit message repeat) indicating the
CPU that the previously transmitted frame has to be loaded again. For frames which are
not longer then 32 bytes the SACCO offers an auto repeat function allowing the
automatic re-transmission of a frame without interrupting the CPU.
Note: For frames which are longer than 32 bytes the auto repeat function must not be
Figure 2-14 Re-Transmission of a Frame
CMDR : XDD/XME
used.
CMDR : XDD
EXIR : XMR
ISTA : XPR
WR XFIFO
WR XFIFO
SACCO
Slave
Complete I-Frame
2-20
RR-Poll
RR-Poll
e.g. CRC Error
Functional Block Description
Group Controller
Master
(PBC)
ITS05835
GC polls,
data is available,
the slave sends an
I-frame,
data is corrupted,
GC polls again,
SACCO emits XMR.
PEB 20560
2003-08