General Procedure For Configuring Dma - Analog Devices ADSP-21261 SHARC Hardware Reference Manual

General Procedure for Configuring DMA

Each DMA is referred to as a channel, and each channel is configured
independently.
There are 22 channels of DMA available on the ADSP-2126x processor—
one channel for the SPI interface, one channel for the parallel port inter-
face, 12 channels via the serial ports, and eight channels for the input data
port (IDP). Another DMA feature is interrupt generation upon comple-
tion of a DMA transfer or upon completion of a chain of DMAs.
General Procedure for Configuring DMA
To configure the ADSP-2126x processor to use DMA, use the following
general procedure.
1. Determine which DMA options you want to use:
• IOP/Core interaction method – Interrupt driven or status
driven (polling)
• DMA transfer method – Chained or Non chained
• Channel priority scheme – fixed or rotating
2. Determine how you want the DMA to operate:
• Determine and set up the data's source and/or destination
addresses (INDEX)
• Set up the word COUNT (data buffer size)
• Configure the MODIFY values (step size)
3. Configure the peripheral(s):
• Serial ports (SPORTs)
• Parallel port (PP)
7-2 ADSP-2126x SHARC Processor Hardware Reference