
ADSP-2126x SHARC Processor Hardware Reference
12-11
Digital Audio Interface
Pin Buffers as Signal Input Pins
When the DAI pin is to be used only as an input, connect the correspond-
ing pin buffer enable to logic low as shown in
the buffer amplifier and allows an off-chip source to drive the value pres-
ent on the DAI pin and at the pin buffer output. When the pin buffer
enable (
PBENxx_I
) is cleared (= 0), the pin buffer output (
PBxx_O
) will be
the signal driven onto the DAI pin by an external source, and the pin buf-
fer input (
PBxx_I
) is not used.
Although not strictly necessary, it is recommended programming practice
to tie the pin buffer input to logic low whenever the pin buffer enable is
tied to logic low. By default, the pin buffer enables are connected to
SPORT pin enable signals that may change value. Tying the pin buffer
input low decouples the line from irrelevant signals and can make code
simpler to debug. It also ensures that no voltage is driven by the pin if a
bug in your code accidentally asserts the pin enable.
Figure 12-8. Pin Buffer as Input
IN
OUT
PIN
ENABLE
PBxx_I
PBxx_O
PINENxx_I
EXTERNAL
PACKAGE
CONNECTION
PIN
INTERFACE
TO SRU
PBxx_O
PAD
DRIVER
PIN BUFFER
OUTPUT
PIN BUFFER
INPUT
(NOT USED)
PIN BUFFER
ENABLE
(= LOW)
Summary of Contents for ADSP-21261 SHARC
Page 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Page 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Page 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Page 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Page 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Page 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Page 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Page 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Page 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Page 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Page 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Page 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...