RELIANCE 45C272内存扩展模块
看门狗定时器计数被重新初始化回输入值，看门狗标志位被清除，每次访问任一寄存器时，看门狗中断输出被清除。定期访问看门狗定时器将防止出现看门狗警报。如果未发生访问，警报将重复出现。看门狗报警寄存器始终读取输入值。实际的倒计时值是内部的，用户无法访问。将零写入寄存器C和D将禁用看门狗报警功能。命令寄存器寄存器B是命令寄存器。在这个寄存器中有掩码位、控制位和标志位。以下段落描述了每一位。Te-位7传输启用-此位启用和禁用内部和外部寄存器之间的数据跟踪。当设置为逻辑零（0）时，跟踪被禁用，冻结外部寄存器中的数据。
The Watchdog Timer count is reinitialized back to the entered value, the Watchdog flag bit is cleared, and the Watchdog interrupt output is cleared every time either of the registers is accessed. Periodic accesses to the Watchdog Timer will prevent the Watchdog Alarm from occurring. If access does not occur, the alarm will be repetitive. The Watchdog Alarm Register always reads the entered value. The actual countdown value is internal and not accessible to the user. Writing zeroes to Registers C and D will disable the Watchdog Alarm feature. Command Register Register B is the Command Register. Within this register are mask bits, control bits, and flag bits. The following paragraphs describe each bit. Te - Bit 7 Transfer Enable - This bit enables and disables the tracking of data between the internal and external registers. When set to a logic zero (0), tracking is disabled, freezing the data in the external register.
