Cirrus Logic CS49DV8C - Manual (Page 8)

8 Copyright 2008 Cirrus Logic, Inc. DS868PP2
CS49DV8C Data Sheet
32-bit Audio DSP Family
memory; and the peripheral bus. Modulo and linear addressing modes are supported, with flexible start
address and increment controls. The service interval for each DMA channel as well as up to 6 interrupt
events, is programmable.
4.2 On-chip DSP Peripherals
4.2.1 Digital Audio Input Port (DAI)
The 12-channel (6 line) DAI port supports a wide variety of data input formats. The port is capable of
accepting PCM or IEC61937. Up to 32-bit word lengths are supported. Additionally support is provided
for audio data input to the DSP via the DAI from an HDMI receiver.
The port has two independent slave-only clock domains. Each data input can be independently assigned
to a clock domain. The sample rate of the input clock domains can be determined automatically by the
DSP, which off-loads the task of monitoring the SPDIF receiver from the host. A time-stamping feature
allows the input data to be sample-rate converted via software.
4.2.2 Digital Audio Output Port (DAO)
There are two DAO ports. Each port can output 8 channels of up to 32-bit PCM data. The port supports
data rates from 32 kHz to 192 kHz. Each port can be configured as an independent clock domain in
slave mode, or the ratio of the two clocks can be set to even multiples of each other in master mode. The
two ports can also be ganged together into a single clock domain. Each port has one serial audio pin that
can be configured as a 192 kHz SPDIF transmitter (data with embedded clock on a single line).
4.2.3 Serial Control Port 1 & 2 (I
2
C
®
or SPI
™
)
There are two on-chip serial control ports that are capable of operating as master or slave in either I 2 C or
SPI modes. SCP1 defaults to slave operation. It is dedicated for external host-control and supports an
external clock up to 25MHz in SPI mode. This high clock speed enables very fast code download,
control or data delivery. SCP2 defaults to master mode and is dedicated for booting from external serial
Flash memory or for audio sub-system control.
4.2.4 External Memory Interface
The external memory interface controller supports up to 128 Mbits of SDRAM, using a 16-bit data bus.
4.2.5 GPIO
Many of the CS49DV8C peripheral pins are multiplexed with GPIO. Each GPIO can be configured as an
output, an input, or an input with interrupt. Each input-pin interrupt can be configured as rising edge,
falling edge, active-low, or active-high.
4.2.6 PLL-based Clock Generator
The low-jitter PLL generates integer or fractional multiples of a reference frequency which are used to
clock the DSP core and peripherals. Through a second PLL divider chain, a dependent clock domain
can be output on the DAO port for driving audio converters. The CS49DV8C defaults to running from the
external reference frequency and can be switched to use the PLL output after overlays have been
loaded and configured, either through master boot from an external FLASH or through host control. A
built-in crystal oscillator circuit with a buffered output is provided. The buffered output frequency ratio is
selectable between 1:1 (default) or 2:1.