Freescale Semiconductor, Inc.
SECTION 6
DMA CONTROLLER MODULE
The direct memory access (DMA) controller module provides for high-speed transfer
capability to/from an external peripheral or for memory-to-memory data transfer. The DMA
module, shown in Figure 6-1, provides two channels that allow byte, word, or long-word
operand transfers. These transfers can be either single or dual address and to either on-
or off-chip devices. The DMA contains the following features:
• Two, Independent, Fully Programmable DMA Channels
• Single-Address Transfers with 32-Bit Address and 32-Bit Data Capability
• Dual-Address Transfers with 32-Bit Address and 16-Bit Data Capability
• Two 32-Bit Transfer Counters
• Four 32-Bit Address Pointers That Can Increment or Remain Constant
• Operand Packing and Unpacking for Dual-Address Transfers
• Supports All Bus-Termination Modes
• Provides Two-Clock-Cycle Internal Module Access
• Provides Two-Clock-Cycle External Access Using MC68340 Chip Selects
• Provides Full DMA Handshake for Burst Transfers and Cycle Steal
DMA
HANDSHAKE
SIGNALS
INTERRUPT
ARBITRATION
DMA CHANNEL 1
SLAVE BIU
I
M
B
MASTER BIU
DMA
HANDSHAKE
SIGNALS
BUS
ARBITRATION
DMA CHANNEL 2
Figure 6-1. DMA Block Diagram
MOTOROLA
MC68340 USER’S MANUAL
6- 1
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