Motorola MPC8260 - Manual (Page 544)

18-20 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA
Part IV. Communications Processor Module
18.8.2.2 Data Transfer Types as Programmed in DCM
Table 18-6 summarizes the types of data transfers according to the DCM programming.
18.8.2.3 Programming DTS and STS
The options for setting STS and DTS depend on (DCM[DMA_WRAP]) and are described
in the following tables for memory/memory and memory/peripheral transfers.
Table 18-6. IDMA Channel Data Transfer Operation
S/D FB Read From Write To Description (Steady-State Operation)
01 0 Memory
(STS = SS_MAX) Peripheral
(DTS = port size
or 32) Read from memory: Filling internal buffer in one DMA transfer.
On the bus: one burst or more, depends on STS
Write to peripheral: In smaller transfers until internal buffer empties.
On the bus: singles or burst, depends on DTS
10 0 Peripheral
(STS = port size or
32) Memory
(DTS =
SS_MAX) Read from peripheral: Filling internal buffer in several DMA
transfers.
On the bus: singles or burst, depends on STS
Write to memory: in one DMA transfer, internal buffer empties.
On the bus: one burst or more, depends on DTS
00 0 Memory
(STS = SS_MAX) Memory
(DTS =
SS_MAX or
less) Read from memory: Filling internal buffer in one DMA transfer.
On the bus: one burst or more, depends on STS
Write to memory: in one transfer or more until internal buffer
empties.
On the bus: singles or bursts, depends on DTS
00 0 Memory
(STS = SS_MAX
or less) Memory
(DTS =
SS_MAX) Read from memory: Filling internal buffer in one or more DMA
transfers.
On the bus: singles or bursts, depends on STS
Write to memory: in one DMA transfer, internal buffer empties.
On the bus: one burst or more, depends on DTS
01 1 Memory to
peripheral
(DTS = port size or
32) Ñ Read transaction from memory while asserting DACK to
peripheral. Peripheral samples the data read from memory.
On the bus: singles or bursts, depends on DTS
10 1 Ñ Peripheral to
memory
(STS = port size
or 32) Write transaction to memory while asserting DACK to peripheral.
Peripheral provides the data that is written to the memory.
On the bus: singles or bursts, depends on STS