Generic Channels
5-15
System DMA Controller
FN is the number of frames in the block, 1
≤
FN
≤
65535.
EN is the number of elements per frame, 1
≤
EN
≤
65535.
ES is the number of bytes per element, ES
∈
{1, 2, 4}.
An element can be:
-
8-bit scalar data, s8
-
16-bit scalar data, s16
-
32-bit scalar data, s32
Types of data transferred in a channel include s8, s16, and s32. FN, EN, and
ES (or data type) are extracted from the configuration registers of the channel.
To set up a channel for a transfer, the software must program two addressing
modes:
-
Source addressing mode
-
Destination addressing mode
These modes work independently. For example, to transfer data from a TIPB
serial port to internal memory, the source-addressing mode is constant (for ex-
ample, when the read operation must be done at a unique register address)
and the destination addressing mode is post-incremented.
The number of frames, the number of elements, and the element size are the
same for source and destination. Each of the following algorithms describes
address computation for each byte of the transfer.
5.3.2.1
Constant Addressing Mode
Address remains constant.
a( i) = SA, 0
≤
i
≤
BS – 1
where:
a(i) is the address of the byte number i within the transfer.
SA is the start address of the transfer.
BS is the block size in bytes.