Acer Intel Celeron G530 KC.53001.CDG Benutzerhandbuch
Produktcode
KC.53001.CDG
46
Intel
®
Celeron
®
Processor on 0.13 Micron Process in the 478-Pin Package
Datasheet
System Bus Signal Quality Specifications
3.3.4
Activity Factor
Activity Factor (AF) describes the frequency of overshoot (or undershoot) occurrence relative to a
clock. Since the highest frequency of assertion of any signal is every other clock, an AF = 1
indicates that the specific overshoot (or undershoot) waveform occurs EVERY OTHER clock
cycle. Thus, an AF = 0.01 indicates that the specific overshoot (or undershoot) waveform occurs
one time in every 200 clock cycles.
clock. Since the highest frequency of assertion of any signal is every other clock, an AF = 1
indicates that the specific overshoot (or undershoot) waveform occurs EVERY OTHER clock
cycle. Thus, an AF = 0.01 indicates that the specific overshoot (or undershoot) waveform occurs
one time in every 200 clock cycles.
For source synchronous signals (address, data, and associated strobes), the activity factor is in
reference to the strobe edge because the highest frequency of assertion of any source synchronous
signal is every active edge of its associated strobe. An AF = 1 indicates that the specific overshoot
(undershoot) waveform occurs every strobe cycle.
reference to the strobe edge because the highest frequency of assertion of any source synchronous
signal is every active edge of its associated strobe. An AF = 1 indicates that the specific overshoot
(undershoot) waveform occurs every strobe cycle.
The specifications provided in
through
show the maximum pulse duration
allowed for a given overshoot/undershoot magnitude at a specific activity factor. Each table entry is
independent of all others, meaning that the pulse duration reflects the existence of overshoot/
undershoot events of that magnitude ONLY. A platform with an overshoot/undershoot that just
meets the pulse duration for a specific magnitude where the AF < 1, means that there can be no
other overshoot/undershoot events, even of lesser magnitude (note that if AF = 1, then the event
occurs at all times and no other events can occur).
independent of all others, meaning that the pulse duration reflects the existence of overshoot/
undershoot events of that magnitude ONLY. A platform with an overshoot/undershoot that just
meets the pulse duration for a specific magnitude where the AF < 1, means that there can be no
other overshoot/undershoot events, even of lesser magnitude (note that if AF = 1, then the event
occurs at all times and no other events can occur).
Notes:
1. Activity factor for AGTL+ signals is referenced to BCLK[1:0] frequency.
2. Activity factor for source synchronous (2X) signals is referenced to ADSTB[1:0]#.
3. Activity factor for source synchronous (4X) signals is referenced to DSTBP[3:0]# and
DSTBN[3:0]#.
3.3.5
Reading Overshoot/Undershoot Specification Tables
The overshoot/undershoot specification for the Celeron processor on 0.13 micron process is not a
simple single value. Many factors are needed to determine what the over/undershoot specification
is. In addition to the magnitude of the overshoot, the following parameters must also be known: the
width of the overshoot (as measured above VCC), and the activity factor (AF). To determine the
allowed overshoot for a particular overshoot event, the following must be done:
simple single value. Many factors are needed to determine what the over/undershoot specification
is. In addition to the magnitude of the overshoot, the following parameters must also be known: the
width of the overshoot (as measured above VCC), and the activity factor (AF). To determine the
allowed overshoot for a particular overshoot event, the following must be done:
1. Determine the VID voltage, System Bus speed, and signal group that a particular signal falls
into and use the appropriate table.
2. Determine the magnitude of the overshoot (relative to VSS).
3. Determine the activity factor (how often does this overshoot occur?).
4. Next, from the appropriate specification table, determine the maximum pulse duration
(in nanoseconds) allowed.
5. Compare the specified maximum pulse duration to the signal being measured. If the pulse
duration measured is less than the pulse duration shown in the table, then the signal meets the
specifications.
specifications.
The above procedure is similar for undershoot after the undershoot waveform has been converted
to look like an overshoot. Undershoot events must be analyzed separately from overshoot events
because the two are mutually exclusive.
to look like an overshoot. Undershoot events must be analyzed separately from overshoot events
because the two are mutually exclusive.