IS200ISBDG1A工控模块卡件,备件模块
“1”，以便看门狗定时器工作。请注意，由于复位后所有寄存器都默认为零，因此在复位后看门狗定时器始终被禁用。重置后，应用软件必须重新启用看门狗定时器，以便看门狗定时器继续运行。启用看门狗定时器后，应用程序软件必须在选定的超时时间内刷新看门狗定时器，以防止生成重置或SERR#。通过对WDT保活寄存器（WKPA）执行写入来刷新看门狗定时器。写入的数据无关紧要。WDT保活寄存器（WKPA）启用后，通过在所选超时时间段内写入位于BAR2中地址偏移0x0C处的WDT保命寄存器（WKBA），防止看门狗定时器重置系统。写入此位置的数据无关紧要。65 NVSRAM 3 NVSRAM VMIVME-7750提供32KB的非易失性SRAM。该存储器被映射到从BAR1中的地址开始的32K地址空间中。该内存随时可用，支持从PCI总线进行字节、短字和长字访问。当板的电源断开时，此内存的内容将保留。VME控制下表显示VMIVME-7750的寄存器定义（与BAR0的偏移量）。表3-3寄存器定义与BAR0寄存器名称偏移VMECOMM 0x00位名称位定义MEC_SEL 0主大端点启用位1=大端点0=小端点位SEC_SEL 1从大端点激活位1=大端点0＝小端点ABLE 2辅助BERR逻辑启用位1＝Aux。BERR启用0=辅助。BERR禁用BTO 3总线错误计时器启用1=启用0=禁用BTOV[1:0]5:4超时值00-16uS 01-64uS 10-256uS 11-1.00mS BERRI 6 BERR中断启用1=中断启用0=中断禁用BERRST 7 BERR状态读取/清除位1=清除BERR状态0=不执行任何操作SFENA 8在WDT超时时启用VME SYSFAIL生成0=禁用66 3 VMIVME-7750产品手册有关BAR0的更多信息，请参阅第56页的表3-2“PCI配置空间寄存器”。未使用9未使用BPENA 10 Endian转换旁路位1=旁路0=未绕过ECENA 11 Endian转换位1=启用0=禁用未使用31:12未使用VBAR 0x04 VME_ADDR所有锁存VME地址VBAM 0x08 VME_ADDR5:0锁存VMD地址修改器未使用31:6未使用SEC_SEL 0x001表3-3寄存器定义与BAR0的偏移（续）寄存器名称偏移67闪存磁盘3闪存磁盘VMIVME-7750具有可选的板载Compact Flash大容量存储系统，容量高达512 Mbyte。该闪存磁盘在用户看来是一个智能ATA（IDE）磁盘驱动器，具有与“旋转介质”IDE硬盘驱动器相同的功能和功能。VMIVME-7750 BIOS包括一个选项，允许板从闪存磁盘启动。配置闪存磁盘作为辅助IDE总线主设备驻留在VMIVME-7750上（辅助IDE总线从设备不可分配）。
“1” in order for the Watchdog Timer to function. Note that since all registers default to zero after reset, the Watchdog Timer is always disabled after a reset. The Watchdog Timer must be re-enabled by the application software after reset in order for the Watchdog Timer to continue to operate. Once the Watchdog Timer is enabled, the application software must refresh the Watchdog Timer within the selected timeout period to prevent a reset or SERR# from being generated. The Watchdog Timer is refreshed by performing a write to the WDT Keepalive register (WKPA). The data written is irrelevant. WDT Keepalive Register (WKPA) When enabled, the Watchdog Timer is prevented from resetting the system by writing to the WDT Keepalive Register (WKPA) located at offset 0x0C from the address in BAR2 within the selected timeout period. The data written to this location is irrelevant. 65 NVSRAM 3 NVSRAM The VMIVME-7750 provides 32KBytes of non-volatile SRAM. This memory is mapped in 32K of address space starting at the address in BAR1. This memory is available at any time and supports byte, short word and long word accesses from the PCI bus. The contents of this memory is retained when the power to the board is removed. VME Control The following table shows the register definitions for the VMIVME-7750 (offset from BAR0). Table 3-3 Register Definitions Offset From BAR0 Register Name Offset VMECOMM 0x00 Bit Name Bit Definition MEC_SEL 0 Master big-endian enable bit 1=Big Endian 0=Little Endian bit SEC_SEL 1 Slave Big-Endian enable bit 1=Big Endian 0=Little Endian ABLE 2 Auxiliary BERR logic enable bit 1=Aux. BERR enabled 0=Aux. BERR disabled BTO 3 Bus error timer enabled 1=enabled 0=disabled BTOV [1:0] 5:4 Timeout value 00 - 16uS 01 - 64uS 10 -256uS 11 - 1.00mS BERRI 6 BERR interrupt enable 1=Interrupt enabled 0=Interrupt disabled BERRST 7 BERR status read/clear bit 1=Clear BERR status 0=Do nothing SFENA 8 Enables generation of VME SYSFAIL upon WDT timeout 1= Enable SYSFAIL generation 0=Disable 66 3 VMIVME-7750 Product Manual Please refer to Table 3-2, “PCI Configuration Space Registers,” on page 56 for more information concerning BAR0. Unused 9 Not Used BPENA 10 Endian conversion bypass bit 1=Bypass 0=Not bypassed ECENA 11 Endian conversion bit 1= Enabled 0=Disabled Unused 31:12 Not Used VBAR 0x04 VME_ADDR All Latched VME Address VBAM 0x08 VME_ADDR 5:0 Latched VME Address Modifier Unused 31:6 Not Used SEC_SEL 0x001 Table 3-3 Register Definitions Offset From BAR0 (Continued) Register Name Offset 67 Flash Disk 3 Flash Disk The VMIVME-7750 features an optional on-board Compact Flash mass storage system with a capacity of up to 512 Mbyte. This Flash Disk appears to the user as an intelligent ATA (IDE) disk drive with the same functionality and capabilities as a “rotating media” IDE hard drive. The VMIVME-7750 BIOS includes an option to allow the board to boot from the Flash Disk. Configuration The Flash Disk resides on the VMIVME-7750 as the secondary IDE bus master device (the secondary IDE bus slave device is not assignable).
