ADSP-21362/ADSP-21363/ADSP-21364/ADSP-21365/ADSP-21366
Rev. F | Page 7 of 56 | March 2010
The entire PWM module has four groups of four PWM outputs
each. Therefore, this module generates 16 PWM outputs in
total. Each PWM group produces two pairs of PWM signals on
the four PWM outputs.
The PWM generator is capable of operating in two distinct
modes while generating center-aligned PWM waveforms: single
update mode or double update mode. In single update mode,
the duty cycle values are programmable only once per PWM
period. This results in PWM patterns that are symmetrical
about the midpoint of the PWM period. In double update
mode, a second updating of the PWM registers is implemented
at the midpoint of the PWM period. In this mode, it is possible
to produce asymmetrical PWM patterns that produce lower
harmonic distortion in 3-phase PWM inverters.
Digital Audio Interface (DAI)
The digital audio interface (DAI) provides the ability to connect
various peripherals to any of the DSP’s DAI pins (DAI_P20–1).
Programs make these connections using the signal routing unit
(SRU, shown in Figure 1).
The SRU is a matrix routing unit (or group of multiplexers) that
enables the peripherals provided by the DAI to be intercon-
nected under software control. This allows easy use of the
DAI-associated peripherals for a wider variety of applications by
using a larger set of algorithms than is possible with nonconfig-
urable signal paths.
The DAI includes six serial ports, an S/PDIF receiver/transmit-
ter, a DTCP cipher, a precision clock generator (PCG), eight
channels of asynchronous sample rate converters, an input data
port (IDP), an SPI port, six flag outputs and six flag inputs, and
three timers. The IDP provides an additional input path to the
ADSP-2136x core, configurable as either eight channels of I
2
S
serial data or as seven channels plus a single 20-bit wide syn-
chronous parallel data acquisition port. Each data channel has
its own DMA channel that is independent from the processor’s
serial ports.
For complete information on using the DAI, refer to the
ADSP-2136x SHARC Processor Hardware Reference.
Serial Ports
The processor features six synchronous serial ports that provide
an inexpensive interface to a wide variety of digital and mixed-
signal peripheral devices such as Analog Devices’ AD183x fam-
ily of audio codecs, ADCs, and DACs. The serial ports are made
up of two data lines, a clock, and a frame sync. The data lines
can be programmed to either transmit or receive and each data
line has a dedicated DMA channel.
Serial ports are enabled via 12 programmable and simultaneous
receive or transmit pins that support up to 24 transmit or 24
receive channels of audio data when all six SPORTs are enabled,
or six full duplex TDM streams of 128 channels per frame.
The serial ports operate at a maximum data rate of f
PCLK
/4.
Serial port data can be automatically transferred to and from
on-chip memory via dedicated DMA channels. Each of the
serial ports can work in conjunction with another serial port to
provide TDM support. One SPORT provides two transmit sig-
nals while the other SPORT provides the two receive signals.
The frame sync and clock are shared.
Serial ports operate in four modes:
• Standard DSP serial mode
•Multichannel (TDM) mode
•I
2
S mode
• Left-justified sample pair mode
Left-justified sample pair mode is a mode where in each frame
sync cycle two samples of data are transmitted/received—one
sample on the high segment of the frame sync, the other on the
low segment of the frame sync. Programs have control over var-
ious attributes of this mode.
Each of the serial ports supports the left-justified sample pair
and I
2
S protocols (I
2
S is an industry-standard interface com-
monly used by audio codecs, ADCs, and DACs, such as the
Analog Devices AD183x family), with two data pins, allowing
four left-justified sample pairs or I
2
S channels (using two stereo
devices) per serial port, with a maximum of up to 24 I
2
S
channels. The serial ports permit little-endian or big-endian
transmission formats and word lengths selectable from 3 bits to
32 bits. For the left-justified sample pair and I
2
S modes, data-
word lengths are selectable between 8 bits and 32 bits. Serial
ports offer selectable synchronization and transmit modes as
well as optional μ-law or A-law companding selection on a per
channel basis. Serial port clocks and frame syncs can be inter-
nally or externally generated.
S/PDIF-Compatible Digital Audio Receiver/Transmitter
The S/PDIF transmitter has no separate DMA channels. It
receives audio data in serial format and converts it into a
biphase encoded signal. The serial data input to the transmitter
can be formatted as left-justified, I
2
S, or right-justified with
word widths of 16, 18, 20, or 24 bits.
The serial data, clock, and frame sync inputs to the S/PDIF
transmitter are routed through the signal routing unit (SRU).
They can come from a variety of sources such as the SPORTs,
external pins, the precision clock generators (PCGs), or the
sample rate converters (SRC) and are controlled by the SRU
control registers.
Digital Transmission Content Protection (DTCP)
The DTCP specification defines a cryptographic protocol for
protecting audio entertainment content from illegal copying,
intercepting, and tampering as it traverses high performance
digital buses, such as the IEEE 1394 standard. Only legitimate
entertainment content delivered to a source device via another
approved copy protection system (such as the DVD content
scrambling system) is protected by this copy protection system.
This feature is available on the ADSP-21362 and
ADSP-21365 processors only. Licensing through DTLA is
required for these products. Visit www.dtcp.com for more
information.