peb20560 Infineon Technologies Corporation, peb20560 Datasheet - Page 57

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

In the case of several shorter frames, up to 17 frames may be stored in the RFIFO.
Nevertheless, only one frame is stored in the CPU accessible part of the RFIFO. E.g., if
frame i (or the last part of frame i) is stored in the accessible RFIFO-part, up to 16 short
frames may be stored in the other half (i +1, i +2, …, i +n, n ≤16). This behavior is
illustrated in Figure 2-8 (right).
Note: After every frame a receive status byte is appended, specifying the status of the
When using the DMA-mode, the SACCO requests fixed size block transfers (4, 8, 16 or
32 bytes). The valid byte count is determined by reading the registers RBCH, RBCL
following the RME-interrupt.
Transmit FIFO
The transmit FIFO (XFIFO) provides a 2 × 32 bytes capability to intermediately store
transmit data.
In interrupt mode the user loads the data and then executes a transmit command. When
the frames are longer than 32 bytes, a XPR-interrupt is issued as soon as the accessible
XFIFO-part is available again.
The status of the bit MODE:CFT (continuous frame transmission) defines whether a new
frame can be loaded as soon as the XFIFO is available or after the current transmission
was terminated.
Figure 2-9
Semiconductor Group
Frame Preparation
Copy Data to Inaccessable
frame (e.g. if the CRC-check is o.k.).
Transmit Serial Data
Frame Transmission
XPR
XFIFO Loading, Continuous Frame Transmission Disabled (CFT = 0)
XFIFO Part
Frame n
XPR
(40 Bytes)
Frame n
2-11
XPR
Frame n+1
Functional Block Description
(32 Bytes)
Frame n+1
PEB 20560
XPR
ITD05831
2003-08