Hello everyone, today we will learn about the power supply, clock,

PG, and reset circuits in the Apple A2159 circuit

We have talked about the boot circuit in the last video

When the CPU receives the switch signal,

it will send SLP_S*# and CPU_C10_GATE# to the power supply chip,

and communicate with the T2 chip through the eSPI bus

The T2 chip will notify the power supply chip to turn on the power supply through the I2C bus

First, after the power supply chip receives CPU_C10_GATE#,

it will control to generate PP1V_S3 VCCST power supply

And output PP1V_S0SW to supply power to the VCCSTG pin of the CPU

Then, the power chip outputs PVCCIO_EN, PVCCPLLOC_EN and PVDDQ_EN

to turn on the main power supply PP1V2_S3 of the memory respectively

And go with the CPU_C10_GATE# signal to generate PVCCIOS0_EN_FILT_BUF,

to turn on PVCCIO_S0_CPU, to provide power to the CPU,

and to turn on PP1V2_S0SW at the same time

PP1V2_S3 is the main memory power supply for memory chips U2300, U2400, U2500 and U2600

The PP1V2_S0 and PPVCIO_S0_CPU here mainly provide the main power supply

for the VCCIO and VCCPLL_OC of the CPU

After the VCCIO power supply is normal,

a PVCCIO_PGOOD power good signal will be generated to the power chip

The power chip will send ALL_SYS_PWRGD signal to correspond with SMC_RSMRST_L,

generating ALL_SYS_PWRGD_R

To correspond with another signal to generate the power supply PPVCEDRAM_S0_CPU

This power supply provides power to the VCCOPC and VCCEOPIO pins of the CPU

In addition, this ALL_SYS_PWRGD_R generates CPU_VCCST_PWRGD to the CPU through the synchronizer

At the same time, it will also generate an open signal for the CPU power supply

This CPU power supply chip is called ISL95828

After it gets the power supply and open signal, it will control the generation of VCCSA of the CPU,

which supplies power to the VCCSA pin of the CPU, which is the system housekeeper power supply of the CPU

After the power supply of each channel is normal,

the 24MHz crystal oscillator of the CPU starts to vibrate and outputs the clocks of each channel

The CPU delays to get the PCH_PWROK and SYS_PWROK sent by the T2 chip,

and the SYS_RESET# signal, and then delays to generate the platform reset signal

After the CPU receives the VCCST_PWRGD signal,

it sends a DDR_VTT_CNTL signal to the S3 pin of U8100 to control the VTT power supply of the memory

The signal is called MEMVTT_EN after being renamed by the gate circuit

After each power supply is normal, the CPU gets the PG signal,

sends out various clocks, and sends out a platform reset

Then, the CPU will send out an SVID signal to control the power supply of the CPU core

It provides core power supply to the VCCCORE pin of the CPU

After the CPU power supply is normal,

it will read the program through the T2 chip and start self-test

After testing the memory, the CPU sends the SVID signal again to the CPU power supply chip

to control the generation of integrated display power supply VCCGT

Ok, this is the generation process of power supply, clock, reset and PG signal