Web• Read Operations: It is often desirable to read the value of a Counter without disturbing the count in progress. This is easily done in the 8254. • There are three possible methods for reading the counters: a simple read operation, the Counter Latch Command, and the Read-Back Command. • Each is explained below. The first method is to ... WebREAD-BACK COMMAND The Read-Back Command in the 8254 allows the user to read the count and the status of the counter; this command is not available in the 8253. The format of the command is shown in Figure 7.6(a). The command is written in the control register, and the count of the specified counter(s) can be latched if COUNT (bit D5) is 0.

Intel 8253 - Programmable Interval Timer - tutorialspoint.com

Web• (RD) Read: A “low” on this input pin enables 8255A to send the data or status information to the CPU on the data bus. In essence, it allows the CPU to “read from” the 8255. • (WR) Write: A “low” on this input pin enables the CPU to write data or control words into the 8255. • (A0 and A1): Port Select 0 and Port Select 1. These input signals, in http://dev.tutorialspoint.com/microprocessor/microprocessor_intel_8253_programmable_interval_timer.htm green clean carpet cleaning service reviews

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Web8254: Counter Latch Command This Counter Latch Command is written to the Control Word Register, which is selected when A1 A0 = 11. The SC1 and SC0 bits select one of the three … WebApr 17, 2014 · 8254 Programmable Interval Timer by vijay Apr. 17, 2014 • 59 likes • 41,488 views Download Now Download to read offline Engineering Technology Business this ppt … WebThe 8254 supports the counter latch operation in two ways. The first way is to set bits RW1 and RW0 to 0. This latches the count of the selected counter in a 16-bit hold register. The second way is to perform a latch operation under the read-back command. Set bits SC1 and SC0 to 1 and CNT = 0. green clean carpet machine missoula