MF3129-J8CATXX 查看數據表（PDF） - MITSUBISHI ELECTRIC
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MF3129-J8CATXX Datasheet PDF : 16 Pages
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MITSUBISHI MEMORY CARD
STATIC RAM CARDS
5. SUMMARY
MF3XXX-J8CATXX series is the Static RAM cards which has 8/16 bit changeable data-bus width.
The card has a replaceable lithium main battery to maintain data in memory and has an auxiliary battery to
maintain data in memory while the main battery is replaced. When the card is not use or the supply voltage
drops, the main battery will automatically maintain data in memory.
6. FUNCTIONAL DESCRIPTION
The function of the card is determined by the combination of the following five control signals,
REG#, CE1#, CE2#, OE#, WE#; active low signals. (Please refer to section 10 FUNCTION TABLE on page 5)
(1)COMMON MEMORY FUNCTION
When REG# signal is high level, the common memory area is selected.
(a)READ MODE
To read, WE# is set high level and CE1# or CE2# is set low level and the memory address is applied at inputs
A0-A21(4MB). Setting OE# low level executes the reading with output at data-bus. It is available to make the
following functions according to the combination of CE1# and CE2#.
When CE1# is set low level and CE2# is set high level, the card operates as an 8 bit data-bus width card.
The data can be dealt with lower data-bus(D0-D7).
When both CE1# and CE2# are set low level, the card operates as a 16 bit data-bus width card.
At this mode LSB of address-bus (A0) is ignored.
In addition odd byte can be accessed through upper data-bus(D8-D15) when CE1# is set high level and CE2# is
set low level. This mode is useful when handling only odd bytes in the 16 bit data-bus interface system (A0 is
ignored).
When both CE1# and CE2# are set high level, the card becomes a standby mode where the card consumes
low power and the data-bus is placed in high impedance state (above functions of CE1# and CE2# are the same
as in the following modes).
When both OE# and WE# are set high level, the card becomes a output disable mode and the data-bus is
placed in high impedance state.
(b)WRITE MODE
To write, the memory address is first applied at inputs A0-A21(4MB) and the data is applied at output pins.
Setting CE1# or CE2# low level, WE# low level and OE# high level executes the writing.
(2)ATTRIBUTE MEMORY FUNCTION
When REG# is set low level, the attribute memory area is selected. MF3XXX-J8CATXX series accommodates
an attribute memory of 8KB E2PROM on even addresses.
(a)READ MODE
First set CE1# and CE2# low level or high level and select residing address (even address). Data can be read by
setting OE# low level and WE# high level.
(b)WRITE MODE
Writing can be done either by byte-mode or page-mode. The page-mode write is the function to be able to write
data of 32 bytes in a single write cycle. The page address is set by A6 to A13 (Please note that attribute memory
exists in even bytes only). To write, set OE# high level and WE# low level. Data will be latched at the rising
edge of WE#. After the first load unless WE# changes from high level to low level within 30µs, the automatic
erase/program starts and completes in 10ms or before. Page data can be latched if WE# transits from high level
to low level before the 30µs. Page-mode write also executes erase/program operation within 10ms.
The page address must be maintained during the page data loading.
(3)BATTERY
When the card is used for long periods of time, eventually battery exhaustion occurs. If such a situation is
encountered, replace any exhausted battery with a new one as directed in section 21.2 ″REPLACING BATTERY″
(page 14).
The replacement battery model number is indicated under section 21 ″BATTERY SPECIFICATIONS″(page 14).
7. WRITE PROTECT MODE
When the write protect switch is switched on, this card goes into a write protect mode that can read but not
write data. In this mode, WP pin becomes “H” level.
At the shipment the write protect switch is switched off (Normal mode : The card can be written ; WP pin
indicates “L” level).
MITSUBISHI
ELECTRIC
2/16
Apr. 1999 Rev. 1.2
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