pef20550 Infineon Technologies Corporation, pef20550 Datasheet - Page 70

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

Figure 40
Polling of Prepared Data
Behavior of SACCO when a RFIFO Overflow Occurs in Auto-mode
When the RFIFO overflows during the reception of an I-frame, a control response with
overflow indication is transmitted, the overflow information is stored in the corresponding
receive status byte. When additional poll frames are received while the RFIFO is still
occupied, an RFO (receive frame overflow) interrupt is generated. Depending on the
type of the received poll frame different responses are generated:
I-frame:
RR-poll:
Semiconductor Group
CMDR : XPD/
ISTA : RME
XME/AREP
ISTA : XPR
WR XFIFO
RD RFIFO
– control response with overflow indication
– RR-response, when no direct data was stored in the XFIFO
– I-frame, when direct data was stored in the XFIFO
(exception: when the command "transmit prepared data" (AxH) is received
and prepared data is available in the XFIFO, an I-frame (with data) is
issued)
SACCO
Slave
Complete I-Frame
I-Frame (Ax )
I-Frame (D0 )
(prepare data)
Control Resp.
I-Frame
70
H
H
e.g. CRC Error
Group Controller
Master
(PBC)
ITS05837
Functional Description
GC emits an I-frame
with a command byte
requesting the preparation
of a defined data type.
The command has to be
interpreted by software,
a response is generated
automatically.
GC uses the command
Ax to poll the requested
data. The slave reacts
without interrupting
the CPU.
GC uses the command
D0 -EF to acknowledge
received data. The slave
issues a XPR interrupt.
H
H
H
PEB 20550
PEF 20550
01.96