MC68EN360AI25VL Freescale, MC68EN360AI25VL Datasheet - Page 308

• Manufacturer Part Number: MC68EN360AI25VL
• Manufacturer: Freescale

Specifications of MC68EN360AI25VL

• Family Name: M68000
• Device Core: ColdFire
• Device Core Size: 32b
• Frequency (max): 25MHz
• Instruction Set Architecture: RISC
• Operating Supply Voltage (max): 3.3V
• Operating Supply Voltage (min): 2.7V
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 240
• Package Type: FQFP
• Lead Free Status / RoHS Status: Compliant

System Integration Module (SIM60)
6.13 PROGRAMMING MODEL
The user interfaces with the memory controller using eight identical sets of two registers, the
BR and OR. There are also two global registers in the memory controller: the GMR and the
MSTAT.
6.13.1 Global Memory Register (GMR)
The 32-bit read-write GMR contains selections that are common to the entire memory con-
troller: DRAM refresh properties, DRAM bank properties, SRAM bank properties, and some
global SRAM/DRAM properties. The reserved bits (4–0) should be written with zero.
The following bits are used for DRAM refresh properties.
RCNT7–RCNT0—Refresh Counter Period
RFEN—Refresh Enable
RCYC1–RCYC0—Refresh Cycle Length
6-64
RCNT7 RCNT6 RCNT5 RCNT4 RCNT3 RCNT2 RCNT1 RCNT0
WBT40
31
15
These bits determine the refresh period according to the following equation:
Example: For a 25-MHz system clock and a required refresh rate of 15.6 s per row, the
RFCNT value should be 24 (decimal). 24/(25 MHz/16) = 15.36 s, which is less than the
required refresh period of 15.6 s.
These bits determine the length of a refresh cycle.
0
0
0 = DRAM refresh is disabled.
1 = DRAM refresh is enabled.
00 = The refresh cycle is 4 clocks long, and RAS is negated for 3 phases prior to being
01 = The refresh cycle is 6 clocks long, and RAS is negated for 5 phases prior to being
10 = The refresh cycle is 7 clocks long, and RAS is negated for 5 phases prior to being
11 = The refresh cycle is 8 clocks long, and RAS is negated for 5 phases prior to being
WBTQ
30
14
0
0
asserted.
asserted.
asserted.
asserted.
SYNC
29
13
0
0
EMWS
28
12
0
1
OPAR
27
11
Freescale Semiconductor, Inc.
0
0
Refresh period
For More Information On This Product,
PBEE
26
10
0
0
MC68360 USER’S MANUAL
Go to: www.freescale.com
TSS40
25
0
1
9
NCS
24
0
8
0
=
RFEN
DWQ
23
0
7
0
System clk/16
RFCNT+1
RCYC1 RCYC0
DW40
22
0
6
0
GAMX
21
0
5
0
PGS2
20
—
0
4
0
PGS1
19
—
0
3
0
SUPERVISOR SPACE ONLY
PGS0
18
—
0
2
0
DPS1
17
—
0
1
0
DPS0
16
—
0
0
0