3DS508PP1
EP7312
High-Performance System-on-Chip with SDRAM and Digital Audio Interface
OVERVIEW
(cont.)
Power Management
The EP7312 i s designed for ultra-lo w-power operati on. Its
core operates at only 2.5 V, while its I/O has an operation
range of 2.5 V–3.3 V. The device has three basic power
states:
Operating — This state is the full performance state. All
the clocks and peripheral log ic are enable d.
Idle — This state is the same as the Operating State,
except the CPU clock is halted while waiting for an
event such as a key press.
Standby — This state is equivalent to the computer
being switched off (no display), and the main oscilla-
tor shut down. An event such as a key press can wake-
up the processor.
MaverickKey™ Unique ID
MaverickKey unique hardware programmed IDs are a
solution to the growing concern over secure web content
and commerce. With Internet security playing an impor-
tant role in the delivery of digital media such as books or
music, t radi tional softwa re met ho ds are quickly becoming
unreliable. The MaverickKey unique IDs provide OEMs
with a method of utilizing specific hardware IDs such as
those assi gned f or S DMI (Secure Digital Musi c I nit ia tive)
or any oth er aut hen ti cat ion mechanism.
Both a speci fic 32- bit I D as well as a 12 8-bi t random ID is
programmed into the EP7312 through the use of laser
probing technology. These IDs can then be used to match
secure copyri ghted content with t he ID of the target de vice
the EP7312 is powering, and then deliver the copyrighted
information over a secure connection. In addition, secure
transactions can benefit by also matching device IDs to
server IDs. MaverickKey IDs provide a level of hardware
security required for today’s Internet appliances.
Memory Interfaces
There are two main external memory interfaces. The first
one is the ROM / SRAM / FLASH-style interface t hat has
programmable wait-stat e timings and includ es burst-mode
capabil ity, with eight ch ip sel ect s dec odi ng six 256 Mbyte
sections of addressable space. For maximum flexibility,
each bank can be specified to be 8-, 16-, or 32-bits wide.
This allows the use of 8-bit-wide boot ROM options to
minimiz e overall syst em c ost. The on-chip boo t ROM can
be used in product manufacturing to serially download sys-
tem code into system FLASH memory. To further mini-
mize system memory requirements and cost, the ARM
Thumb‚ instruction set is supported, providing for the use
of high-speed 32-bit operations in 16-bit op-codes and
yieldi ng in dust r y-leading co de d ensi ty.
The second is the programmable 4- or 32-bit-wide
SDRAM interface that allows direct connection of up to
four internal banks of SDRAM, totaling 256 Mbits. To
assure the lowest possible power consumption, the EP7312
supports self-refresh DRAMs, which are placed in a low-
power state by the device when it enters the low-power
St andb y State.
A DMA address generator is also provided that fetches
video display data for the LCD controller from main
SDRAM memory . The display frame buffer start address is
programmable. In addition, the built-in LCD controller can
utilize external or internal SRAM for memory, thus elimi-
nating the need f or S DRA Ms.
Digital Audio Capability
The EP7312 uses its powerful 32-bit RISC processing
engine to implement audio decompression algorithms in
software. The n ature of the on-b oard RISC processor and
the availability of efficient C-compilers and other software
development tools, ensures that a wide range of audio
decompression algorithms can easily be ported to and run
on the EP7312.
Serial Interfaces
The EP7312 includes two 16550-type UARTs for RS-232
serial communications, both of which have two 16-byte
FIFOs for receiving and transmitting data. The UARTs
support bi t rates up to 1 15. 2 kbits/ s. An IrDA SIR protocol
encoder / d ecoder can b e optionall y switched int o the RX /
TX signals to / from one of the UAR Ts to enable these sig-
nals to d rive an infrared communicat ion interface directly.
Improved Digital Audio Interface (DAI)
The EP7312 integrates an interface to enable a direct co n -
nection to many low cost, low power, high quality audio
converters. In particular, the DAI can directly interface
with the Crystal‚ CS43L41 / 42 / 43 low-power audio
DACs and the Crystal‚ CS53L32 low-power ADC. Some
of these devices featur e dig ita l bass and treble boost, dig i-
tal volume control and compressor - l i miter functions.
Packaging
The EP7312 is availabl e in a 208-pin LQFP package and a
256-ball PBGA package.
System Design
As shown in system bloc k diag ram, simply a dding desired
memory and peripherals to the highly integrated EP7312
completes a low-power system solution. All necessary
interface log ic is i ntegrat ed on-ch ip.