peb20560 Infineon Technologies Corporation, peb20560 Datasheet - Page 67

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

Figure 2-15 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
µP can read and interpret the received data (e.g. following the PBC-protocol). A PBC
compatible control response is generated automatically.
E.g., if the local µP recognizes the request to “prepare data” it may load the XFIFO and
set CMDR:XPD/XME.
Semiconductor Group
XDD/XME/AREP
ISTA : XPR
WR XFIFO
CMDR :
SACCO
Slave
Complete I-Frame
Complete I-Frame
RR-Acknowledge
2-21
RR-Poll
RR-Poll
e.g. CRC Error
Group Controller
Functional Block Description
Master
(PBC)
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 20560
2003-08