ABB 5SHY3545L0005 336A4954ARP2高压变频器IGCT模块
写入计时器是通过首先写入控制字，然后写入初始计数来编程的。控制字的格式如表4-2至4-6所示。所有控制字被写入控制字寄存器，而初始计数被写入各个定时器寄存器。初始计数的格式由控制字定时器锁存命令（参见读取部分）确定0 1读取/写入最低有效字节1 0读取/写入最高有效字节1 1读取/写最低有效字节，然后是最重要的*RW位指定这是计时器锁存命令还是读/写事务的字节顺序。二进制计时器16位1二进制编码十进制（BCD）计时器（4个十进位）*BCD位指定计时器计数值是二进制还是BCD。编程82C54时，只需遵循两个规则。1.对于每个计时器，必须首先写入控制字。2.初始计数必须遵循控制字中指定的格式（仅限最低有效字节，仅限最高有效字节，或最低有效字节然后是最高有效字节）。只要遵守这些规则，任何编程顺序都是可以接受的。
Writing The Timers are programmed by first writing a Control Word and then the initial count. The format of the Control Word is shown in Tables 4-2 through 4-6. All Control Words are written into the Control Word Register while the initial counts are written into the individual Timer registers. The format of the initial count is determined by the Control Word.Timer Latch Command (see Reading section) 0 1 Read/Write least significant byte only 1 0 Read/Write most significant byte only 1 1 Read/Write least significant byte first, then most significant *The RW bits specify whether this is a Timer Latch command or the byte ordering of the Read/Write transaction.Binary Timer 16-bits 1 Binary Coded Decimal (BCD) Timer (4 Decades) * The BCD bit specifies whether the Timer count value is in Binary or BCD.When programming the 82C54, only two rules need to be followed. 1. For each Timer, the Control Word must be written first. 2. The initial count must follow the format specified in the Control Word (least significant byte only, most significant byte only, or least significant byte then most significant byte). As long as these rules are adhered to, any programming sequence is acceptable.
