NHE6300ESB S L7XJ Intel, NHE6300ESB S L7XJ Datasheet - Page 112

• Manufacturer Part Number: NHE6300ESB S L7XJ
• Manufacturer: Intel

Specifications of NHE6300ESB S L7XJ

• Lead Free Status / RoHS Status: Compliant

5.5.5.1
5.5.5.2
Intel
DS
112
®
6300ESB I/O Controller Hub
Note: Performing a direct read from the counter will not return a determinate value, because
With the simple read and counter latch command methods, the count must be read
according to the programmed format; specifically, when the counter is programmed for
two byte counts, two bytes must be read. The two bytes do not have to be read one
right after the other. Read, write, or programming operations for other counters may be
inserted between them.
Simple Read
The first method is to perform a simple read operation. The counter is selected through
port 40h (counter 0), 41h (counter 1), or 42h (counter 2).
the counting process is asynchronous to read operations. However, in the case of
counter 2, the count may be stopped by writing to the GATE bit in port 61h.
Counter Latch Command
The Counter Latch Command, written to port 43h, latches the count of a specific
counter at the time the command is received. This command is used to ensure that the
count read from the counter is accurate, particularly when reading a two-byte count.
The count value is then read from each counter's Count Register as was programmed
by the Control Register.
The count is held in the latch until it is read or the counter is reprogrammed. The count
is then unlatched. This allows reading the contents of the counters on the fly without
affecting counting in progress. Multiple Counter Latch Commands may be used to latch
more than one counter. Counter Latch commands do not affect the programmed mode
of the counter in any way.
When a Counter is latched and then, some time later, latched again before the count is
read, the second Counter Latch command is ignored. The count read will be the count
at the time the first Counter Latch command was issued.
Order Number: 300641-004US
Intel
®
6300ESB ICH—5
November 2007