w83977atg Winbond Electronics Corp America, w83977atg Datasheet - Page 137

• Manufacturer Part Number: w83977atg
• Description: W83877tf Plus Kbc, Gp I/o, Wake-up, Fir, Cir, Pb-free
• Manufacturer: Winbond Electronics Corp America

13.1 Start Frame
There are two modes of operation for the IRQSER Start frame: Quiet mode and Continuous mode.
In the Quiet mode, the peripheral drives the SERIRQ signal active low for one clock, and then tri-
states it. This brings all the states machines of the peripherals from idle to active states. The host
controller will then take over driving IRQSER signal low in the next clock, and will continue driving the
IRQSER low for programmable 3 to 7 clock periods. This makes the total number of clocks low for 4 to
8 clock periods. After these clocks, the host controller will drive the IRQSER high for one clock and
then tri-states it.
In the Continuous mode, only the host controller initiates the START frame to update IRQ/Data line
information. The host controller drives the IRQSER signal low for 4 to 8 clock periods. Upon a reset,
the IRQSER signal is defaulted to the Continuous mode for the host controller to initiate the first Start
frame.
13.2 IRQ/Data Frame
Once the start frame has been initiated, all the peripherals must start counting frames based on the
rising edge of the start pulse. Each IRQ/Data Frame is three clocks: Sample phase, Recovery phase,
and Turn-around phase.
During the Sample phase, the peripheral drives SERIRQ low if the corresponding IRQ is active. If the
corresponding IRQ is inactive, then IRQSER must be left tri-stated. During the Recovery phase, the
peripheral device drives the IRQSER high. During the Turn-around phase, the peripheral device
leaves the IRQSER tri-stated.
The IRQ/Data Frame has a number of specific order, as shown in Table 13-1.
Table 13-1 IRQSER Sampling periods
IRQ/DATA FRAME
10
11
12
13
1
2
3
4
5
6
7
8
9
SIGNAL SAMPLED
IRQ10
IRQ11
IRQ12
IRQ0
IRQ1
IRQ3
IRQ4
IRQ5
IRQ6
IRQ7
IRQ8
IRQ9
SMI
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W83977ATF/W83977ATG
Publication Release Date: May 2006
# OF CLOCKS PAST START
11
14
17
20
23
26
29
32
35
38
2
5
8
Revision 0.6