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Hello everyone, in this lesson we will take a look at the workflow of the trigger circuit

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The workflow of the trigger circuit is relatively simple, there are only 5 steps in total

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The first step is to trigger the switch

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Then the switch signal enters the IO

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The switch signal here refers to the signal connected to the power button

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The power button is connected to the jumper interface of the mainboard

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The connection method of this jumper interface has been explained in the previous course.

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Next, let's find the position number of the jumper interface in the bitmap

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The position number of the jumper interface is shown in the figure

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We search for this position number directly in the circuit diagram

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After finding the jumper socket in the main board, we also found the switch signal at the sixth pin

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We directly search for this switch signal

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It can be seen that this signal is directly sent to the 104 pin of the IO

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The first step of the trigger circuit has

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Let's draw this step

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Next, after the IO receives the switch signal, it will send a power-on signal to the bridge, PWRBTN##

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It is a wake-up signal, used to wake up the bridge and let the bridge start to work

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Under normal circumstances, this PWRBTN# is a high-low-high jump

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High is 3V, low is 0V

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When the bridge receives the PWRBTN# signal, and the standby condition of the bridge is normal,

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then the bridge will send out the SLP signal

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That is, SLP_S3#, SLP_S4#, SLP_A#, SLP_LAN#, etc.

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Among them, SLP_S3# is given to IO

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When the IO receives this SLP_S3#, it will pull down the green line of the ATX power supply, which is PS_ON#

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This PS_ON# is the power on signal

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When the green line is pulled low, the ATX power supply will start to work,

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outputting red 5V, orange 3V and yellow 12V for power supply

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This trigger circuit is the circuit where the IO and the bridge work together

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For IO, the trigger circuit can be simplified into four steps,

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that is, the switch enters the IO, the IO sends out PWRBTN#,

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the IO receives SLP_S3#, and the IO pulls down the green line

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These are the four steps of IO triggering

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It is also described in this common IO key pin

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It can be seen that there are a total of 4 trigger pins

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From left to right, they correspond to the switch pin, the pin that sends out PWRBTN#,

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the pin that receives SLP_S3#, and the pin that pulls down the green line

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Its order is the same as the order of the 4 steps triggered

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Well, the above is the workflow of the trigger circuit