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AM29PL160CB-70REF 数据表(PDF) 20 Page - Advanced Micro Devices |
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AM29PL160CB-70REF 数据表(HTML) 20 Page - Advanced Micro Devices |
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20 / 44 page ![]() 18 Am29PL160C 22143C7 May 9, 2006 D A TA SH EE T device returns to reading array data and addresses are no longer latched. Figure 2 illustrates the algorithm for the erase opera- tion. See the Program/Erase Operations tables in “AC Characteristics” for parameters, and to Figure 16 for timing diagrams. Sector Erase Command Sequence Sector erase is a six bus cycle operation. The sector erase command sequence is initiated by writing two unlock cycles, followed by a set-up command. Two ad- ditional unlock write cycles are then followed by the address of the sector to be erased, and the sector erase command. Table 10 shows the address and data requirements for the sector erase command sequence. The device does not require the system to preprogram the memory prior to erase. The Embedded Erase algo- rithm automatically programs and verifies the sector for an all zero data pattern prior to electrical erase. The system is not required to provide any controls or tim- ings during these operations. After the command sequence is written, a sector erase time-out of 50 µs begins. During the time-out period, additional sector addresses and sector erase com- mands may be written. Loading the sector erase buffer may be done in any sequence, and the number of sec- tors may be from one sector to all sectors. The time between these additional cycles must be less than 50 µs, otherwise the last address and command might not be accepted, and erasure may begin. It is recom- mended that processor interrupts be disabled during this time to ensure all commands are accepted. The in- terrupts can be re-enabled after the last Sector Erase command is written. If the time between additional sector erase commands can be assumed to be less than 50 µs, the system need not monitor DQ3. Any command other than Sector Erase or Erase Sus- pend during the time-out period resets the device to reading array data. The system must rewrite the command sequence and any additional sector ad- dresses and commands. The system can monitor DQ3 to determine if the sector erase timer has timed out. (See the “DQ3: Sector Erase Timer” section.) The time-out begins from the rising edge of the final WE# pulse in the command sequence. Once the sector erase operation has begun, only the Erase Suspend command is valid. All other commands are ignored. When the Embedded Erase algorithm is complete, the device returns to reading array data and addresses are no longer latched. The system can determine the sta- tus of the erase operation by using DQ7, DQ6, or DQ2. (Refer to “Write Operation Status” for information on these status bits.) Figure 2 illustrates the algorithm for the erase opera- tion. Refer to the Program/Erase Operations tables in the “AC Characteristics” section for parameters, and to Figure 16 for timing diagrams. Erase Suspend/Erase Resume Commands The Erase Suspend command allows the system to in- terrupt a sector erase operation and then read data from, or program data to, any sector not selected for erasure. This command is valid only during the sector erase operation, including the 50 µs time-out period during the sector erase command sequence. The Erase Suspend command is ignored if written during the chip erase operation or Embedded Program algo- rithm. Writing the Erase Suspend command during the Sector Erase time-out immediately terminates the time-out period and suspends the erase operation. Ad- dresses are “don’t-cares” when writing the Erase Suspend command. When the Erase Suspend command is written during a sector erase operation, the device requires a maxi- mum of 20 µs to suspend the erase operation. However, when the Erase Suspend command is writ- ten during the sector erase time-out, the device immediately terminates the time-out period and sus- pends the erase operation. After the erase operation has been suspended, the system can read array data from or program data to any sector not selected for erasure. (The device “erase suspends” all sectors selected for erasure.) Normal read and write timings and command definitions apply. Reading at any address within erase-suspended sec- tors produces status data on DQ7–DQ0. The system can use DQ7, or DQ6 and DQ2 together, to determine if a sector is actively erasing or is erase-suspended. See “Write Operation Status” for information on these status bits. After an erase-suspended program operation is com- plete, the system can once again read array data within non-suspended sectors. The system can deter- mine the status of the program operation using the DQ7 or DQ6 status bits, just as in the standard program operation. See “Write Operation Status” for more information. The system may also write the autoselect command sequence when the device is in the Erase Suspend mode. The device allows reading autoselect codes even at addresses within erasing sectors, since the codes are not stored in the memory array. When the device exits the autoselect mode, the device reverts to the Erase Suspend mode, and is ready for another valid operation. See “Autoselect Command Sequence” for more information. The system must write the Erase Resume command (address bits are “don’t care”) to exit the erase sus- |
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