pef20550 Infineon Technologies Corporation, pef20550 Datasheet - Page 69

• Manufacturer Part Number: pef20550
• Description: Extended Line Card Interface Controller Elic
• Manufacturer: Infineon Technologies Corporation

Figure 39
Re-transmission of a Frame with Auto-Repeat Function
Polling of Prepared Data
If polling "prepared data" a different procedure is used. The group controller issues an
I-frame with a set poll bit and the first data byte is interpreted as command byte.
When prepared data was loaded into the XFIFO (CMDR:XPD/XME was set) the
reception of a command byte equal to AxH initiates the transmission of an I-frame.
For "prepared data" the auto repeat function must be selected! Due to this the polling
can be repeated without interrupting the CPU.
An I-frame with a data byte equal to D0H-EFH is interpreted as an acknowledgment for
previously transmitted data. An XPR-interrupt is issued and the XFIFO is reset.
All other I-frames are stored in the RFIFO and a RME-interrupt is generated. The local
compatible control response is generated automatically.
E.g., if the local P recognizes the request to "prepare data" it may load the XFIFO and
set CMDR:XPD/XME.
Semiconductor Group
P can read and interpret the received data (e.g. following the PBC-protocol). A PBC
XDD/XME/AREP
ISTA : XPR
WR XFIFO
CMDR :
SACCO
Slave
Complete I-Frame
Complete I-Frame
RR-Acknowledge
RR-Poll
RR-Poll
69
e.g. CRC Error
Group Controller
Master
(PBC)
Functional Description
ITS05836
GC polls,
data is available,
the slave sends an
I-frame,
data is corrupted,
GC polls again,
SACCO retransmits,
GC acknowledges,
SACCO emits XPR.
PEB 20550
PEF 20550
01.96