ADSP-214xx SHARC Processor Hardware Reference 9-7
Digital Application/Digital Peripheral Interfaces
DAI/DPI Signal Naming Conventions
Each peripheral associated with the DAI/DPI does not have any dedicated
I/O pins for off-chip communication. Instead, the I/O pin is only accessi-
ble in the chip internally and is known as an internal node. Every internal
node of a DAI peripheral (input or output) is given a unique mnemonic.
The convention is to begin the name with an identifier for the peripheral
that the signal is coming to/from followed by the signal’s function. A
number is included if the DAI contains more than one peripheral type (for
example, serial ports), or if the peripheral has more than one signal that
performs this function (for example, IDP channels). The mnemonic
always ends with _I if the signal is an input, or with _O if the signal is an
output (Figure 9-2).
I/O Pin Buffers
Within the context of the SRU, physical connections to the DAI pins are
replaced by a logical interface known as a pin buffer. This is a three termi-
nal active device capable of sourcing/sinking output current when its
driver is enabled, and passing external input signals when disabled. Each
pin has an input, an output, and an enable as shown in Figure 9-3. The
inputs and the outputs are defined with respect to the pin, similar to a
peripheral device. This is consistent with the SRU naming convention.
Figure 9-2. Example SRU Mnemonic
SPORT0_CLK_O
PERIPHERAL
SIGNAL
FUNCTION
DIRECTION
RELATIVE
TO SIGNAL’S
PERIPHERAL
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