NH82801HBM S LB9A Intel, NH82801HBM S LB9A Datasheet - Page 136

• Manufacturer Part Number: NH82801HBM S LB9A
• Description: CONTROLLER HUB, ICH8M, I/O, 82801HBM
• Manufacturer: Intel

Specifications of NH82801HBM S LB9A

• Power Dissipation Pd: 2.4W
• Digital Ic Case Style: BGA
• No. Of Pins: 676
• Pci Bus Type: I/O Controller Hub
• Pci Express Base Spec: PCIe 1.1
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

5.7.1
136
Timer Programming
The counter/timers are programmed in the following fashion:
Only two conventions need to be observed when programming the counters. First, for
each counter, the control word must be written before the initial count is written.
Second, the initial count must follow the count format specified in the control word
(least significant byte only, most significant byte only, or least significant byte and then
most significant byte).
A new initial count may be written to a counter at any time without affecting the
counter's programmed mode. Counting is affected as described in the mode definitions.
The new count must follow the programmed count format.
If a counter is programmed to read/write two-byte counts, the following precaution
applies: A program must not transfer control between writing the first and second byte
to another routine which also writes into that same counter. Otherwise, the counter will
be loaded with an incorrect count.
The Control Word Register at port 43h controls the operation of all three counters.
Several commands are available:
Table 49
1. Write a control word to select a counter.
2. Write an initial count for that counter.
3. Load the least and/or most significant bytes (as required by Control Word bits 5, 4)
4. Repeat with other counters.
• Control Word Command. Specifies which counter to read or write, the operating
• Counter Latch Command. Latches the current count so that it can be read by the
• Read Back Command. Reads the count value, programmed mode, the current
of the 16-bit counter.
mode, and the count format (binary or BCD).
system. The countdown process continues.
state of the OUT pins, and the state of the Null Count Flag of the selected counter.
lists the six operating modes for the interval counters.
Intel
®
Functional Description
ICH8 Family Datasheet