EMERSON 5X00321G01 DCS卡
每種設備類(lèi)型的訪(fǎng)問(wèn)定時(shí)都是可編程的，取決于初始化期間VPD中的設備定時(shí)數據。MVME7100上提供了硬件閃存組寫(xiě)保護開(kāi)關(guān)，以啟用NOR閃存的寫(xiě)保護。無(wú)論NOR閃存控制/狀態(tài)寄存器中的軟件閃存寫(xiě)保護位的狀態(tài)如何，當該開(kāi)關(guān)處于ON時(shí)，寫(xiě)保護都會(huì )啟用。當該開(kāi)關(guān)為OFF時(shí)，寫(xiě)防護由軟件閃存寫(xiě)防護位的狀態(tài)控制，并且只能通過(guò)清除NOR閃存控制/狀態(tài)寄存器的該位來(lái)禁用。請注意，F_WE_HW位反映交換機的狀態(tài)，并且僅是軟件可讀的，而F_WP_SW位同時(shí)支持讀和寫(xiě)操作。MVME7100提供了一個(gè)雙引導選項，用于從引導閃存庫中的兩個(gè)單獨的引導映像（稱(chēng)為引導塊a和引導塊B）中的一個(gè)引導。引導塊a、B的大小各為1MB，位于引導閃存空間的頂部（最高地址）2MB。
Access timing for each device type is programmable and depends on the device timing data found in the VPD during initialization.A hardware flash bank write protect switch is provided on the MVME7100 to enable write protection of the NOR Flash. Regardless of the state of the software flash write protect bit in the NOR Flash Control/Status register, write protection is enabled when this switch is ON. When this switch is OFF, write protection is controlled by the state of the software flash write protect bits and can only be disabled by clearing this bit in the NOR Flash Control/Status register. Note that the F_WE_HW bit reflects the state of the switch and is only software readable whereas the F_WP_SW bit supports both read and write operations. The MVME7100 provides a dual boot option for booting from one of two separate boot images in the boot flash bank which are referred to as boot block A and boot block B. Boot blocks A and B are each 1MB in size and are located at the top (highest address) 2MB of the boot flash memory space.
