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EX29LV320-90RTCI Datasheet(PDF) 9 Page - Excel Semiconductor Inc. |
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EX29LV320-90RTCI Datasheet(HTML) 9 Page - Excel Semiconductor Inc. |
9 / 59 page ES I ES I 9 Rev. 0E May 25, 2006 ES29DL320 Excel Semiconductor inc. ADVANCED INFORMATION be protected prior to the first sector unprotection write cycle to avoid any over-erase due to the intrin- sic erase characteristics of the protection cell. After the unprotection operation, all previously protected sectors will need to be individually re-protected. Standard microprocessor bus cycle timings are used in the unprotection and unprotect verification opera- tions. Three unprotect methods are provided in the ES29DL320 device. All unprotection and unprotect verification cycles are summarized in detail at the Table 1. - In-system unprotection - A9 High-voltage unprotection - Temporary sector unprotection In-System Unprotection “In-system unprotection”, the primary method, requires VID (8.5V~12.5V) on the RESET# with A6=1, A1=1, and A0=0. This method can be imple- mented either in-system or via programming equip- ment. This method uses standard microprocessor bus cycle timing. Refer to Fig. 29 for timing diagram and Fig. 4 for the unprotection algorithm. A9 High-Voltage Unprotection “High-voltage unprotection”, the alternate method intended only for programming equipment, must force VID (8.5V~12.5V) on address pin A9 and con- trol pin OE# with A6=1, A1=1 and A0=0. Refer to Fig. 32 for timing diagram and Fig. 6 for the unpro- tection algorithm. Temporary Sector Unprotect This feature allows temporary unprotection of previ- ously protected sectors to change data in-system. The Sector Unprotect mode is activated by setting the RESET# pin to VID (8.5V~12.5V). During this mode, formerly protected sectors can be pro- grammed or erased by selecting the sector addresses. Once VID is removed from the RESET# pin, all the previously protected sectors are pro- tected again. Fig. 1 shows the algorithm, and Fig. 27 shows the timing diagrams for this feature. WRITE PROTECT ( WP# ) The write protect function provides a hardware method of protecting certain boot sectors without using VID. This function is one of two provided by the WP#/ACC pin. If the system asserts VIL on the WP#/ACC pin, the device disables program and erase functions in the two “outermost” 8Kbytes boot sectors indepen- dently of whether those sectors were protected or unprotected using the method described in “Sector Group Protection and Unprotection”. The two outer- most of 8 Kbyte boot sectors are the two sectors containing the lowest addresses in a bottom-boot- configured device, or the two sectors containing the highest addresses in a top-boot-configured device. If the system asserts VIH on the WP#/ACC pin, the device reverts to whether the two outermost 8 Kbyte boot sectors were last set to be protected or unprotected. That is, sector protection or unprotec- tion for these two sectors depends on whether they were last protected or unprotected using the method described in “Sector Group Protection and Unprotection”. Note that the WP#/ACC pin must not be left floating or unconnected; inconsistent behavior of the device may result. Notes: 1. All protected sectors are unprotected (If WP#/ACC = VIL, outermost boot sectors will remain protected). 2. All previously protected sectors are protected once again. Figure 1. Temporary Sector Unprotect Operation START RESET# = VID (Note 1) Perform Erase or Program Operations RESET# = VIH Temporary Sector Unprotect Completed (Note 2) |
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