Address Space
Address Space
DMA
Controller
Address Space
Address Space
Fixed Address To Block Of Addresses
Fixed Address To Fixed Address
Block Of Addresses To Fixed Address
Block Of Addresses To Block Of Addresses
DMA
Controller
DMA
Controller
DMA
Controller
DMA Operation
341
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
DMA Controller
11.2 DMA Operation
The DMA controller is configured with user software. The setup and operation of the DMA is discussed in
the following sections.
11.2.1 DMA Addressing Modes
The DMA controller has four addressing modes. The addressing mode for each DMA channel is
independently configurable. For example, channel 0 may transfer between two fixed addresses, while
channel 1 transfers between two blocks of addresses. The addressing modes are shown in
.
The addressing modes are:
•
Fixed address to fixed address
•
Fixed address to block of addresses
•
Block of addresses to fixed address
•
Block of addresses to block of addresses
The addressing modes are configured with the DMASRCINCR and DMADSTINCR control bits. The
DMASRCINCR bits select if the source address is incremented, decremented, or unchanged after each
transfer. The DMADSTINCR bits select if the destination address is incremented, decremented, or
unchanged after each transfer.
Transfers may be byte to byte, word to word, byte to word, or word to byte. When transferring word to
byte, only the lower byte of the source word transfers. When transferring byte to word, the upper byte of
the destination word is cleared when the transfer occurs.
Figure 11-2. DMA Addressing Modes