RELIANCE 45C37B自动远程I/O接口
图4-7显示了VMIVME-7740中如何使用看门狗定时器的通用框图。看门狗定时器寄存器映射在NVRAM地址$D8000到$D800D的底部14个位置。表4-12显示了每个看门狗寄存器的地址、内容和范围。寄存器0到A是时钟、日历和时间寄存器。寄存器B是命令寄存器。寄存器C和D是看门狗报警寄存器。看门狗定时器包含14个8位宽的寄存器。这些寄存器包含所有的时间、报警、看门狗、控制和数据信息。时钟日历、报警和看门狗寄存器具有包含数据副本的外部（用户可访问）和内部存储器位置。外部存储器位置独立于内部功能，除了通过传输递增的内部值定期更新外。寄存器0、1、2、4、6、8、9和A包含时间和二进制编码十进制（BCD）的数据信息。寄存器3、5和7包含BCD格式的每日时间报警信息。命令寄存器（寄存器B）包含二进制数据。
Figure 4-7 shows a generalized block diagram of how the Watchdog Timer is used in the VMIVME-7740. The Watchdog Timer registers are memory-mapped in the bottom fourteen locations of NVRAM addresses $D8000 through $D800D. Table 4-12 shows the address, content, and the range of each Watchdog Register.Registers 0 through A are Clock, Calendar, Time of Day Registers. Register B is the Command Register. Registers C and D are Watchdog Alarm Registers. The Watchdog Timer contains 14 registers which are 8-bits wide. These registers contain all of the Time of Day, Alarm, Watchdog, Control, and Data information. The Clock Calendar, Alarm, and Watchdog Registers have both external (user accessible) and internal memory locations containing copies of the data. The external memory locations are independent of the internal functions except that they are updated periodically by the transfer of the incremented internal values. Registers 0, 1, 2, 4, 6, 8, 9, and A contain Time of Day and Data information in Binary Coded Decimal (BCD). Registers 3, 5, and 7 contain the Time of Day Alarm information in BCD. The Command Register (Register B) contains data in binary.
