Symphony DSP56724/DSP56725 Multi-Core Audio Processors, Rev. 0
2-26
Freescale Semiconductor
Signal Descriptions
LOE/
LSDRAS/
LGPL2
Output
LOE/
LSDRAS/
LGPL2
GPCM Output Enable / SDRAM RAS / General-Purpose Line 2
Asserted/Negated—This signal controls the output buffer of memory when
accessing memory/devices in GPCM mode. For SDRAM accesses, this signal
is the row address strobe (RAS). This signal is one of six general purpose lines
when in UPM mode, and drives a value programmed in the UPM array.
Uses an internal pull-up resistor.
LSDCAS/
LGPL3
Output
LSDCAS/
LGPL3
SDRAM CAS / General-Purpose Line 3
Asserted/Negated—In SDRAM mode, drives the column address strobe (CAS).
This signal is one of six general purpose signals when in UPM mode, and drives
a value programmed in the UPM array.
Uses an internal pull-up resistor.
LGTA/
LGPL4/
UPWAIT
Input/Output
LGTA/
LGPL4/
UPWAIT
GPCM Terminate Access / General-Purpose Line 4 / UPM Wait
Asserted/Negated—This signal is an input in GPCM mode and is used for
transaction termination. This signal may also be configured as one of six general
purpose output signals when in UPM mode or as an input to force the UPM
controller to wait for the memory/device.
Uses an internal pull-up resistor.
LGPL5
Input/Output
LGPL5
General-Purpose Line 5
Asserted/Negated—This signal is one of six general purpose signals when in
UPM mode, and drives a value programmed in the UPM array.
Uses an internal pull-up resistor.
LBCTL
Output
LBCTL
Data Buffer Control
When a GPCM- or UPM-controlled bank is accessed, the memory controller
activates a data buffer control signal (BCTL) for the external memory. Access to
an SDRAM machine-controlled bank does not activate the buffer control. The
buffer control can be disabled by setting ORx[BCTLD].
Asserted/Negated—The LBCTL pin normally functions as a Write/Read control
for a bus transceiver connected to the LAD lines. Because LBCTL remains high
after reset and during address phases, an external data buffer must not drive the
LAD lines in conflict with the EMC when LBCTL is high.
Uses an internal pull-up resistor.
LA[2:0]
Output
GPIO
Disconnected
External Memory Non-Multiplexed Address LSBs
All bits driven on LA[2:0] are defined for 24-bit port sizes.
Asserted/Negated—Even though the EMC shares an address and data bus, up
to three least significant bits of the RAM address always appear on the
dedicated address pins LA[2:0]. These may be used, unlatched, in place of
LAD[2:0], to connect the three least significant bits of the address for address
phases. For some RAM devices, such as fast-page DRAM, LA[2:0] serve as the
column address offset during a burst access.
PA[26:24]
Input or
Output or
Disconnected
GPIO Port A, Pin26–Pin24
When the EMC is configured as GPIO, these signals are individually
programmable as input, output, or internally disconnected. PA24 is multiplexed
with LA0; PA25 is multiplexed with LA1; PA26 is multiplexed with LA2.
The default state after reset for these signals is GPIO disconnected.
Internal Pull-Down Resistor for these 3 signals.
Table 2-18. External Memory: EMC Signals (Continued)
Signal Name
Type
State during
Reset
Description