Symphony DSP56724/DSP56725 Multi-Core Audio Processors Reference Manual, Rev. 0
Freescale Semiconductor
21-1
Chapter 21
External Memory Controller (EMC)
21.1
Introduction
NOTE
The EMC is not available on the DSP56725 device.
The External Memory Controller (EMC) provides a seamless interface to many types of memory devices
and peripherals over a shared address and data bus and dedicated control signals. The memory controller
in the EMC is responsible for controlling a parameterized number of memory banks shared by a high
performance SDRAM machine, a general-purpose chip-select machine (GPCM), and up to three
user-programmable machines (UPMs).
As such, the EMC supports a glueless interface to synchronous DRAM (SDRAM), SRAM, EPROM, flash
EPROM, burstable RAM, regular DRAM devices, extended data output DRAM devices, and other
peripherals. Support signals for external address latch (LALE) allows the multiplexing of address with
data lines in devices with limited pin counts.
The EMC includes write protection features, and also a bus monitor to ensure that each internal transaction
is terminated within a user-specified period.
Figure 21-1. EMC Block Diagram
LOE
LGTA
LBCTL
LGPL[3:0]
LGPL4/UPWAIT
LGPL5
LSDA10
LSDWE
LSDRAS
LSDCAS
LCS[7:0]
LWE
LSDDQM
LAD[23:0]
LALE
LA[2:0]
LCLK
LCKE
LSYNC_IN
LSYNC_OUT
GPCM
SDRAM
UPM
Refresh
Internal Bus
ClkGen
Memory
Interface
C
o
nt
ro
l S
igna
l
Ge
n
e
ra
to
r
UPM Ram
Control &
Status
Registers
Controller
Controller
Controller
PLL
& Data Buffer
Address MUX
Bus Monitor
Controllers
EMC