peb20560 Infineon Technologies Corporation, peb20560 Datasheet - Page 54

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

Semiconductor Group
Figure 2-3
In receive direction the behavior of pin DRQR is implemented correspondingly. If k × 32
bytes are transferred, pin DRQR is deactivated with the rising edge of RD of
DMA-transfer ((k × 32) 1) and it is activated again with the next rising edge of DACK
(or CSS), if there are further bytes to transfer (Figure 2-5). When a fast DMA-controller
is used (> 16 MHz), byte n (or bytes k × 32) will be transferred immediately (Figure 2-4).
However, if 4, 8, 16 or 32 bytes have to be transferred (only these discrete values are
possible in receive direction), DRQR is deactivated with the falling edge of RD
(Figure 2-6).
Figure 2-4
Figure 2-5
Timing Diagram for DMA-Transfers (slow) Transmit (n < 32,
remainder of a long message or n = k × 32)
Timing Diagram for DMA-Transfer (fast) Receive (n = k × 32)
Timing Diagram for DMA-Transfers (slow) Receive (n = k × 32)
DRQT
WR
CSS,
DACK
Cycle
DRQR
RD
CSS,
DACK
Cycle
DRQR
RD
CSS,
DACK
Cycle
n-2
n-2
n-1
n-1
n-2
2-8
n-1
n
Functional Block Description
ITD05827
n
n
ITD05826
ITD05828
PEB 20560
2003-08