
FUJITSU LIMITED
PRELIMINARY and CONFIDENTIAL
MB86293 CORAL_LQ
Graphics Controller
Specifications Rev. 1.1
148
10.2.2 Graphics memory interface registers
MMR (Memory I/F Mode Register)
Register
address
Bit number
31 3029 28 27 26 25 24 23 2221 20 1918 17 1615 1413 12 1110 9 8 7 6 5 4 3 2 1 0
Bit field name
*1
tWR
Reserved *1 *1 TRRD
TRC
HostBaseAddress + FFFC
H
TRP
TRAS
TRCD LOWD
RTS
RAW
ASW
CL
R/W
RW RW
R
R1
W0
R
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
Initial value
0 0
Don’t care
1 0
00
0000
00
000
00
00
000
000
0
000
*1: Reserved
This register sets the mode of the graphics memory interface. A value must be written to this register
after a reset. (When default setting is performed, a value must also be written to this register.) Only
write once to this register; do not change the written value during operation.
This register is not initialized at a software reset.
Bit 2 to 0
CL (CAS Latency)
Sets the CAS latency. Write the same value as this field, to the mode register for
SDRAM
011
CL3
010
CL2
Other than
the above
Setting disabled
Bit 3
ASW (Attached SDRAM bit Width)
Sets the bit width of the data bus (memory bus width mode)
1
64 bit
0
32 bit
Bit 6 to 4
SAW (SDRAM Address Width)
Sets the bit width of the SDRAM address
001
15 bit BANK 2 bit ROW 13 bit COL 9 bit SDRAM
111
14 bit BANK 2 bit ROW 12 bit COL 9 bit SDRAM
110
14 bit BANK 2 bit ROW 12 bit COL 8 bit SDRAM
101
13 bit BANK 2 bit ROW 11 bit COL 8 bit SDRAM
100
12 bit BANK 1 bit ROW 11 bit COL 8 bit FCRAM
000
14 bit BANK 2 bit ROW 12 bit COL 8 bit SDRAM
Other than
the above
Setting disabled
Bit 9 to 7
RTS (Refresh Timing Setting)
Sets the refresh interval
000
Refresh is performed every 384 internal clocks.
111
Refresh is performed every 1552 internal clocks.
001 to 110
Refresh is performed every ‘64
×
n’ internal clocks in the 64 to 384 range.