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M750000006 数据表(PDF) 21 Page - SPANSION |
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M750000006 数据表(HTML) 21 Page - SPANSION |
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21 / 129 page ![]() February 6, 2004 Am75PDL191BHHa/Am75PDL193BHHa 19 ADV ANCE I N FO RMAT I O N Requirements for Reading Array Data To read array data from the outputs, the system must drive the OE# and appropriate CE#f1/CE#f2 (PDL129 only) pins to V IL. CE#f1 and CE#f2 are the power con- trol OE# is the output control and gates array data to the output pins. WE# should remain at V IH. The internal state machine is set for reading array data upon device power-up, or after a hardware reset. This ensures that no spurious alteration of the memory content occurs during the power transition. No com- mand is necessary in this mode to obtain array data. Standard microprocessor read cycles that assert valid addresses on the device address inputs produce valid data on the device data outputs. Each bank remains enabled for read access until the command register contents are altered. Refer to the AC Characteristics table for timing specifi- cations and to Figure 14 for the timing diagram. I CC1 in the DC Characteristics table represents the active cur- rent specification for reading array data. Random Read (Non-Page Read) Address access time (t ACC) is equal to the delay from stable addresses to valid output data. The chip enable access time (t CE) is the delay from the stable ad- dresses and stable CE#f1 to valid data at the output inputs. The output enable access time is the delay from the falling edge of the OE# to valid data at the output inputs (assuming the addresses have been sta- ble for at least t ACC–tOE time). Page Mode Read The device is capable of fast page mode read and is compatible with the page mode Mask ROM read oper- ation. This mode provides faster read access speed for random locations within a page. Address bits A22–A3 (A21–A3 for PDL129) select an 8-word page, and address bits A2–A0 select a specific word within that page. This is an asynchronous operation with the microprocessor supplying the specific word location. The random or initial page access is t ACC or tCE and subsequent page read accesses (as long as the loca- tions specified by the microprocessor fall within that page) are t PACC. When CE#f1 and CE#f2 (PDL129 only) are deasserted (CE#f1=CE#f2=V IH), the reasser- tion of CE#f1 or CE#f2 (PDL129 only) for subsequent access has access time of t ACC or tCE. Here again, CE#f1/CE#f2 (PDL129 only) selects the device and OE# is the output control and should be used to gate data to the output inputs if the device is selected. Fast page mode ac ce sse s are obtained by ke ep ing A22–A3 (A21–A3 for PDL129) constant and changing A2 to A0 to select the specific word within that page. Table 2. Page Select Simultaneous Operation In addition to the conventional features (read, pro- gram, erase-suspend read, and erase-suspend pro- gram), the device is capable of reading data from one bank of memory while a program or erase operation is in progress in another bank of memory (simultaneous operation), The bank can be selected by bank ad- dresses (A22–A20) (A21–A20 for PDL129) with zero latency. The simultaneous operation can execute multi-func- tion mode in the same bank. Table 3. Bank Select (PDL129H) Table 4. Bank Select (PDL127H) Word A2 A1 A0 Word 0 000 Word 1 001 Word 2 010 Word 3 011 Word 4 100 Word 5 101 Word 6 110 Word 7 111 Bank CE#f1 CE#f2 A21–A20 Bank 1A 0 1 00, 01, 10 Bank 1B 0 1 11 Bank 2A 1 0 00 Bank 2B 1 0 01, 10, 11 Bank A22–A20 Bank A 000 Bank B 001, 010, 011 Bank C 100, 101, 110 Bank D 111 |
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