7.1.3 Input/Output Pins
Table 7-1 summarizes the refresh controller’s input/output pins.
Table 7-1 Refresh Controller Pins
Signal
Pin
Name
Abbr.
I/O
Function
RFSH
Refresh
RFSH
Output
Goes low during refresh cycles; used
to refresh DRAM and PSRAM
HWR
Upper write/upper column
UW
/
UCAS
Output
Connects to the
UW
pin of 2
WE
address strobe
DRAM or
UCAS
pin of 2
CAS
DRAM
LWR
Lower write/lower column
LW
/
LCAS
Output
Connects to the
LW
pin of 2
WE
DRAM
address strobe
or
LCAS
pin of 2
CAS
DRAM
RD
Column address strobe/
CAS
/
WE
Output
Connects to the
CAS
pin of 2
WE
write enable
DRAM or
WE
pin of 2
CAS
DRAM
CS
3
Row address strobe
RAS
Output
Connects to the
RAS
pin of DRAM
7.1.4 Register Configuration
Table 7-2 summarizes the refresh controller’s registers.
Table 7-2 Refresh Controller Registers
Address
*
Name
Abbreviation
R/W
Initial Value
H'FFAC
Refresh control register
RFSHCR
R/W
H'02
H'FFAD
Refresh timer control/status register
RTMCSR
R/W
H'07
H'FFAE
Refresh timer counter
RTCNT
R/W
H'00
H'FFAF
Refresh time constant register
RTCOR
R/W
H'FF
Note:
*
Lower 16 bits of the address.
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