Motorola PowerQUICC II MPC8280 Series Reference Manual page 416

DMA Controller
• PCI-memory-to-60x-memory transfers—The DMA controller initiates reads on the
PCI bus and stores the data in the DMA queue. Once sufficient data is stored in the
queue, a 60x memory write is initiated. The DMA controller stops the transfer either
for an error condition on the PCI bus or 60x bus, or when no data is left to transfer.
Reading from PCI memory and writing to 60x memory can occur concurrently.
• 60x-memory-to-PCI-memory transfers—The DMA controller initially fetches data
from 60x memory into the DMA queue. As soon as the first data arrives into the
queue, the DMA engine initiates write transactions to PCI memory. The DMA
controller stops the transfer either when there is an error on the PCI bus or 60x bus,
or there is no more data left to transfer. Reading from 60x memory and writing to
PCI memory can occur concurrently.
• 60x-memory-to-60x-memory transfers—The DMA controller begins reading data
from 60x memory and storing it in the DMA queue. Once sufficient data is stored in
the queue, the DMA controller begins writing data to 60x memory space beginning
at the destination address. The process is repeated until there is no more data to
transfer or an error condition has occurred while accessing memory.
9.13.1.6 DMA Registers
Each DMA channel has a set of seven 32-bit registers (mode, status, current descriptor
address, next descriptor address, source address, destination address, and byte count) to
support transactions. This section describes the format of the DMA support registers.
9.13.1.6.1 DMA Mode Registers 0–3 (DMAMRx)
The mode register allows software to start the DMA transfer and to control various DMA
transfer characteristics.
31
Field
Reset
R/W
Addr 0x10502 (DMAMR0); 0x10582 (DMAMR1); 0x10602 (DMAMR2); 0x10682 (DMAMR3)
15 14 13
Field SAHTS DAH
E
Reset
R/W
Addr 0x10500 (DMAMR0); 0x10580 (DMAMR1); 0x10600 (DMAMR2); 0x10680 (DMAMR3)
Figure 9-82. DMA Mode Registers 0–3 (DMAMRx)
Table 9-66 describes DMAMRx fields.
9-94
Freescale Semiconductor, Inc.
—
0000_0000_0000_0000
12 11 10 9
SAHE PRC —
0000_0000_0000_0000
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24 23 21
BWC DM_SEN IRQS
R/W
8 7 6
EOTIE —
R/W
20 19 18 17 16
— DAHTS
4 3 2 1
TEM CTM CC CS
MOTOROLA
0