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Flash ROM and Memory Interface Signals
3-23
3.5 Flash ROM and Memory Interface Signals
Table 3.19
describes the signals for the Flash ROM and Memory
Interface Signals group.
Table 3.19
Flash ROM and Memory Interface Signals
Name
Bump
Type Strength Description
MWE/
AC19
O
4 mA
Memory Write Enable.
This pin is used as a write
enable signal to an external flash memory.
MCE/
AA18
O
4 mA
Memory Chip Enable.
This pin is used as a chip
enable signal to an external EPROM or flash memory
device.
MOE/_
TESTOUT
Y18
O
4 mA
Memory Output Enable.
This pin is used as an output
enable signal to an external EPROM or flash memory
during read operations. It is also used to test the
connectivity of the SYM53C1010 signals in the
“AND-tree” test mode.
MAS0/
AC18
O
4 mA
Memory Address Strobe 0
. This pin is used to latch
in the least significant address byte (bits [7:0]) of an
external EPROM or flash memory. Since the
SYM53C1010 moves addresses eight bits at a time,
this pin connects to the clock of an external bank of
flip-flops that assemble up to a 20-bit address for the
external memory.
MAS1/
AA17
O
4 mA
Memory Address Strobe 1.
This pin is used to latch
in the most significant address byte (bits [15:8]) of an
external EPROM or flash memory. Since the
SYM53C1010 moves addresses eight bits at a time,
this pin connects to the clock of an external bank of
flip-flops that assemble up to a 20-bit address for the
external memory.
MAD[7:0]
Y19, AA19,
AC20,AB20,
AA20,AC22,
AB21, AC23.
I/O
4 mA
Memory Address/Data Bus.
This bus is used in
conjunction with the memory address strobe pins and
external address latches to assemble up to a 20-bit
address for an external EPROM or flash memory. This
bus first issues the least significant byte and finishes
with the most significant bits. It is also used to write
data to a flash memory or read data into the chip from
external EPROM/flash memory. These pins have static
pull-downs.