1. USSR
Applications Processor Subsystem, that is, the application processor subsystem (main CPU processor), ARM's A-series core, now generally has 8 cores, responsible for application processing.
2. RPM
Resource Power Manager, that is, the power manager, ARM's M series core, is responsible for supplying power to each subsystem.
3. MPSS
Modem peripheral subsystem, that is, baseband memory subsystem, ARM A series or DSP core; on-chip memory OCIMEM, which will be used as RAM during operation, and the modem is responsible for processing communication-related services.
4. WCNSS
Wireless connectivity subsystem, that is, the wireless connection subsystem, the core of ARM, is responsible for wireless related services such as Wi-Fi, BT, GPS, and FM.
5. LPASS
Low-power audio subsystem, that is, the low-power audio subsystem, the core of Hexagon DSP, is responsible for audio, sensors and other services.
Between subsystems and between subsystems and peripherals, a large amount of complex data and signals need to be processed frequently, so a variety of interfaces with different standards have emerged. Different platforms use different interfaces.
Such as EMI, UFS, SDIO interface between AP and Memory;
MIPI CSI and DSI interfaces between AP, camera and touch screen;
I2C and SPI interfaces between AP and peripheral sensors;
I2S, PCM/TDM, I2C, SPI, Soundwire, DMIC/PDM interfaces between AP and Codec, Audio PA;
Qlink, DigRF, LVDSRF, RFFE MIPI interface between Modem and RFIC;
PCIe, SDIO, UART, SLIMbus, I2S interfaces between AP and WBG;
I2C, SPMI, SPI, PWM interfaces between PMU and peripheral power devices;
And JTAG, USB, UART interfaces for Debug, etc.