NO:
W90P710 Programming Guide
VERSION:
2.1
PAGE:
27
The above information is the exclusive intellectual property of Winbond Electronics and shall not be disclosed,
distributed or reproduced without permission from Winbond.
Table No.: 1200-0003-07-A
2.3 Registers
Register
Address
R/W
Description
Reset Value
EBICON
0xFFF0.1000 R/W
EBI control register
0x0001.0000
ROMCON
0xFFF0.1004 R/W
ROM/FLASH control register
0x0000.0XFC
SDCONF0
0xFFF0.1008 R/W
SDRAM bank 0 configuration register
0x0000.0800
SDCONF1
0xFFF0.100C R/W
SDRAM bank 1 configuration register
0x0000.0800
SDTIME0
0xFFF0.1010 R/W
SDRAM bank 0 timing control register
0x0000.0000
SDTIME1
0xFFF0.1014 R/W
SDRAM bank 1 timing control register
0x0000.0000
EXT0CON
0xFFF0.1018 R/W
External I/O 0 control register
0x0000.0000
EXT1CON
0xFFF0.101C R/W
External I/O 1 control register
0x0000.0000
EXT2CON
0xFFF0.1020 R/W
External I/O 2 control register
0x0000.0000
EXT3CON
0xFFF0.1024 R/W
External I/O 3 control register
0x0000.0000
CKSKEW
0xFFF0.1F00 R/W
Clock skew control register (for testing)
0xXXXX.0038
2.4 Functional Descriptions
2.4.1 EBI Control Register (EBICON)
The major function of EBICON is to control the SDRAM refreshing timing. This register can
control is used to set the refresh period, clock, and valid time of nWAIT signal. Additionally, the EBI
memory format configuration (Big, or Little Endian) can be known got by reading from the EBI control
register. The auto-refresh rate is controlled by the REFRAT , and SDRAM clock is controlled by
CLKEN.
There are two SDRAM refresh mode, auto-refresh mode and self-refresh mode. If SDRAM is
operated in auto-refresh mode, SDRAM controller refreshes SDRAM every by a period specified by
REFRAT. If SDRAM is in self-refresh mode, it is refreshed by SDRAM itself. Thus if SDRAM is
operated in self-refresh mode, the CLKEN and REFEN can be disabled to reduce save power
consumption. Another way to save reduce power consumption is just to disabling CLKEN, and