Motorola MPC8260 User Manual
MOTOROLA
Chapter 10. Memory Controller
10-51
Part III. The Hardware Interface
10.5 General-Purpose Chip-Select Machine (GPCM)
Users familiar with the MPC8xx memory controller should read Section 10.5.4,
ÒDifferences between MPC8xxÕs GPCM and MPC8260Õs GPCM,Ó Þrst.
ÒDifferences between MPC8xxÕs GPCM and MPC8260Õs GPCM,Ó Þrst.
The GPCM allows a glueless and ßexible interface between the MPC8260, SRAM,
EPROM, FEPROM, ROM devices, and external peripherals. The GPCM contains two basic
conÞguration register groupsÑBRx and ORx.
EPROM, FEPROM, ROM devices, and external peripherals. The GPCM contains two basic
conÞguration register groupsÑBRx and ORx.
Table 10-29 lists the GPCM interface signals on the 60x and local bus.
GPCM-controlled devices can use BCTLx as read/write indicators. The BCTLx signals
appears as R/W in the timing diagrams. See Section 10.2.7, ÒData Buffer Controls
(BCTLx).Ó
appears as R/W in the timing diagrams. See Section 10.2.7, ÒData Buffer Controls
(BCTLx).Ó
Additional control is available in 60x-compatible mode (60x bus only)ÑALEÐexternal
address latch enable
address latch enable
In this section, when a signal is named, the reference is to the 60x or local bus signal,
according to the bank being accessed. Figure 10-40 shows a simple connection between a
32-bit port size SRAM device and the MPC8260.
according to the bank being accessed. Figure 10-40 shows a simple connection between a
32-bit port size SRAM device and the MPC8260.
Table 10-28. Register Settings (Bank-Based Interleaving)
Register
Settings
BRx
BA
Base address
PS
00 = 64-bit port size
DECC
00
WP
0
MS
010 = SDRAM-60x bus
EMEMC
0
ATOM
00
DR
0
V
1
ORx
SDAM
1111_1100_0000
LSDAM
00000
BPD
01
ROWST
010
NUMR
011
PMSEL
0
IBID
0
PSDMR
PBI
0
RFEN
1
OP
000
SDAM
001
BSMA
010
SDA10
011
RFRC
from device data sheet
PRETOACT
from device data sheet
ACTTOROW
from device data sheet
BL
0
LDOTOPRE
from device data sheet
WRC
from device data sheet
EAMUX
0
BUFCMD
0
CL
from device data sheet
Table 10-29. GPCM Interfaces Signals
60x Bus
Local Bus
Comments
CS[0Ð11]
Device select
WE[0Ð7]
LWE[0Ð3]
Write enables for write cycles
OE
LOE
Output enable for read cycles