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M700000002 数据表(PDF) 97 Page - SPANSION |
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M700000002 数据表(HTML) 97 Page - SPANSION |
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97 / 128 page ![]() November 25, 2003 Am70PDL127BDH/Am70PDL129BDH 95 AD VAN C E INFORM ATION controls or timings. The device automatically provides internally generated program pulses and verifies the programmed cell margin. Tables 10 and 11 show the address and data requirements for the word/byte pro- gram command sequence, respectively. When the Embedded Program algorithm is complete, the device then returns to the read mode and ad- dresses are no longer latched. The system can deter- mine the status of the program operation by using DQ7 or DQ6. Refer to the Write Operation Status sec- tion for information on these status bits. Any commands written to the device during the Em- bedded Program Algorithm are ignored. Note that a hardware reset immediately terminates the program operation. The program command sequence should be reinitiated once the device has returned to the read mode, to ensure data integrity. Note that the ACC function and unlock bypass modes are not available when the SecSi Sector is enabled. Programming is allowed in any sequence and across sector boundaries. A bit cannot be programmed from “0” back to a “1.” Attempting to do so may cause the device to set DQ5 = 1, or cause the DQ7 and DQ6 status bits to indicate the operation was suc- cessful. However, a succeeding read will show that the data is still “0.” Only erase operations can convert a “0” to a “1.” Unlock Bypass Command Sequence The unlock bypass feature allows the system to pro- gram words to the device faster than using the stan- dard program command sequence. The unlock bypass command sequence is initiated by first writing two un- lock cycles. This is followed by a third write cycle con- taining the unlock bypass command, 20h. The device then enters the unlock bypass mode. A two-cycle un- lock bypass program command sequence is all that is required to program in this mode. The first cycle in this sequence contains the unlock bypass program com- mand, A0h; the second cycle contains the program address and data. Additional data is programmed in the same manner. This mode dispenses with the initial two unlock cycles required in the standard program command sequence, resulting in faster total program- ming time. Tables 10 and 11 show the requirements for the command sequence. During the unlock bypass mode, only the Unlock By- pass Program and Unlock Bypass Reset commands are valid. To exit the unlock bypass mode, the system must issue the two-cycle unlock bypass reset com- mand sequence. The first cycle must contain the data 90h. The second cycle must contain the data 00h. The device then returns to the read mode. Write Buffer Programming Write Buffer Programming allows the system write to a maximum of 16 words/32 bytes in one programming operation. This results in faster effective programming time than the standard programming algorithms. The Write Buffer Programming command sequence is initi- ated by first writing two unlock cycles. This is followed by a third write cycle containing the Write Buffer Load command written at the Sector Address in which pro- gramming will occur. The fourth cycle writes the sector address and the number of word locations, minus one, to be programmed. For example, if the system will pro- gram 6 unique address locations, then 05h should be written to the device. This tells the device how many write buffer addresses will be loaded with data and therefore when to expect the Program Buffer to Flash command. The number of locations to program cannot exceed the size of the write buffer or the operation will abort. The fifth cycle writes the first address location and data to be programmed. The write-buffer-page is se- lected by address bits A MAX–A4. All subsequent ad- d r ess/data p a irs m u st f a ll wi t h in the selected-write-buffer-page. The system then writes the remaining address/data pairs into the write buffer. Write buffer locations may be loaded in any order. The write-buffer-page address must be the same for all address/data pairs loaded into the write buffer. (This means Write Buffer Programming cannot be per- formed across multiple write-buffer pages. This also means that Write Buffer Programming cannot be per- formed across multiple sectors. If the system attempts to load programming data outside of the selected write-buffer page, the operation will abort. Note that if a Write Buffer address location is loaded multiple times, the address/data pair counter will be decremented for every data load operation. The host sy stem mu st ther efor e ac count fo r load ing a write-buffer location more than once. The counter dec- rements for each data load operation, not for each unique write-buffer-address location. Note also that if an address location is loaded more than once into the buffer, the final data loaded for that address will be programmed. Once the specified number of write buffer locations have been loaded, the system must then write the Pro- gram Buffer to Flash command at the sector address. Any other address and data combination aborts the Write Buffer Programming operation. The device then begins programming. Data polling should be used while monitoring the last address location loaded into the write buffer. DQ7, DQ6, DQ5, and DQ1 should be monitored to determine the device status during Write Buffer Programming. |
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