External Memory Controller (EMC)
Symphony DSP56724/DSP56725 Multi-Core Audio Processors, Rev. 0
Freescale Semiconductor
21-5
LSDWE/
LGPL1
O SDRAM write enable/General-purpose line 1
State
Meaning
Asserted/Negated—This signal is connected to the SDRAM device WE input and acts as the
SDRAM write enable when accessing SDRAM.
This signal is one of six general purpose signals when in UPM mode, and drives a value
programmed in the UPM array
Timing
N/A
LOE/
LSDRAS/
LGPL2
O GPCM output enable/SDRAM RAS/General-purpose line 2
State
Meaning
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.
Timing
N/A
LSDCAS/
LGPL3
O SDRAM CAS/General-purpose line 3
State
Meaning
Asserted/Negated—In SDRAM mode, this signal 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.
Timing
N/A
LGTA/
LGPL4/
UPWAIT
I/O GPCM terminate access/General-purpose line 4/UPM wait
State
Meaning
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.
Timing
N/A
LGPL5
O General-purpose line 5
State
Meaning
Asserted/Negated—This signal is one of six general purpose signals when in UPM mode, and
drives a value programmed in the UPM array.
Timing
N/A
LBCTL
O Data buffer control. The memory controller activates a data buffer control signal (BCTL) for the external
memory when a GPCM- or UPM-controlled bank is accessed. Access to an SDRAM machine-controlled
bank does not activate the buffer control. The buffer control can be disabled by setting ORx[BCTLD].
State
Meaning
Asserted/Negated—The LBCTL pin normally functions as a write/read control for a bus
transceiver connected to the LAD lines. Note that an external data buffer must not drive the LAD
lines in conflict with the EMC when LBCTL is high, because LBCTL remains high after reset and
during address phases.
Timing
N/A
Table 21-2. Detailed Signal Descriptions (Continued)
Signal
I/O
Description