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AM29PL320DB60RWPI 数据表(PDF) 20 Page - Advanced Micro Devices |
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AM29PL320DB60RWPI 数据表(HTML) 20 Page - Advanced Micro Devices |
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20 / 49 page ![]() 18 Am29PL320D June 13, 2005 devices from being used to replace devices that are factory locked. The system accesses the SecSi Sector through a command sequence (see “Enter SecSi ™ Sector/Exit SecSi Sector Command Sequence”). After the system has written the Enter SecSi Sector command se- quence, it may read the SecSi Sector by using the ad- dresses normally occupied by the boot sectors. This mode of operation continues until the system issues the Exit SecSi Sector command sequence, or until power is removed from the device. On power-up the device reverts to sending commands to the boot sec- tors. Factory Locked: SecSi Sector Programmed and Protected At the Factory In a factory locked device, the SecSi Sector is pro- tected when the device is shipped from the factory. The SecSi Sector cannot be modified in any way. The device is available preprogrammed with one of the fol- lowing: ■ A random, secure ESN only ■ Customer code through the ExpressFlash service ■ Both a random, secure ESN and customer code through the ExpressFlash service. In devices that have an ESN, a Bottom Boot device will have the 8-word (4-double word) ESN in the lowest ad- dressable memor y area at addresses 000000h– 000003h in double word mode (or 000000h–000007h in word mode). In the Top Boot device the starting ad- dress of the ESN will be at the bottom of the lowest 8 Kbyte boot sector at addresses 1F8000h–1F8003h in double word mode (or addresses FC0000h–FC0007h in word mode). Customers may opt to have their code programmed by AMD through the AMD ExpressFlash service. AMD programs the customer’s code, with or without the ran- dom ESN. The devices are then shipped from AMD’s factory with the SecSi Sector permanently locked. Contact an AMD representative for details on using AMD’s ExpressFlash service. Customer Lockable: SecSi Sector NOT Programmed or Locked At the Factory If the security feature is not required, the SecSi Sector can be treated as an additional Flash memory space, expanding the size of the available Flash array. Cur- rent version of device has 512 words; future ver- sions will have only 128 words. This should be considered during system design. The SecSi Sec- tor can be read, programmed, and erased as often as required. (In upcoming versions of this device, the SecSi Sector erase function will not be available.) Note that the accelerated programming (ACC) and unlock bypass functions are not available when programming the SecSi Sector. The SecSi Sector can be locked in-system by perform- ing the following steps: ■ Write the three-cycle Enter SecSi Sector Region command sequence. ■ Write 60h to any address (protect command). ■ Wait 150 µs, and then write 40h to address 01h (ver- ify command). ■ Read from address 02h. The data should be 01h. ■ Write the reset command (F0h to any address). ■ Write the four-cycle Exit SecSi Sector command se- quence to return to reading from the array. To verify the protect/unprotect status of the SecSi Sector, follow the algorithm shown in Figure 1. The SecSi Sector lock must be used with caution since, once locked, there is no procedure available for unlocking the SecSi Sector area and none of the bits in the SecSi Sector memory space can be modified in any way. Figure 1. SecSi Sector Protect Verify Write Protect (WP#) The Write Protect function provides a hardware method of protecting certain boot sectors without using VID. If the system asserts VIL on the WP# input, the device disables program and erase functions in Sector 0 (for bottom boot) or Sector 18 (for top boot) independently of whether those sectors were protected or unpro- Write 60h to any address Write 40h to SecSi Sector address with A6 = 0, A1 = 1, A0 = 0 START RESET# = VIH or VID Wait 1 μs Read from SecSi Sector address with A6 = 0, A1 = 1, A0 = 0 If data = 00h, SecSi Sector is unprotected. If data = 01h, SecSi Sector is protected. Remove VIH or VID from RESET# Write reset command SecSi Sector Protect Verify complete |
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