Southbridge

PS4 southbridge contains two processors named EMC and EAP on the same die that are mainly used on boot, during rest mode and for servicing.

Components

Southbridge processors

The two processors are on the same die. It is a SoC (System on Chip).

EMC

EMC could stand for External Micro Controller. EMC was named MediaCon by some people when its name was still unknown.

The role of EMC is to load EMC IPL and EAP kernel, to be an interface for icc for the main APU kernel and Syscon and to offer a debug interface via UART that does not rely on Syscon or main APU. EMC runs its own FreeBSD kernel. It is a Marvell Armada, an ARM-based SoC. Sony stuck a PCIe bridge on it. It exposes ARM peripherals to the x86 side. There is some extra stuff (e.g. HPET, ACPI stuff).

EMC cpuid = 412FC231 (ARM Cortex-M3 r2p1). CPU clock: maybe about 100MHz.

EAP

EAP could stand for External Application Processor.

The role of EAP is to handle media (online Wireless/GbLAN, Bluray Drive and Harddrive) even in standby mode. EAP runs its own FreeBSD kernel in standby mode, activated to handle tasks such as downloading updates while the PS4 is in standby.

EAP consists of Marvell PJ4C B0 rev 1 cores, ARMv7 CORTEX-A8 running FreeBSD 9 kernel. CPU clock: 500MHz. DDR clock: 800MHz.

As EAP Core software is unsigned, unencrypted and easily replaceable on PS4 HDD with a PS4 kernel exploit, it is possible to run homebrew code on EAP processor. See eapdev by Bigboss (psxdev).

Auxiliary components

The Southbridge is connected to the main APU by PCIe PCI_Express x4 and to Syscon by SPI.

It handles several tasks to offload the main processor/APU:

• Network connections: Wireless and GbLAN, including background downloading and PlayGo
• File handling (Bluray Drive, Harddrive and USB 3.0), including background caching
• Main serial flash handling

Aeolia chip is connected to its own 256MB (or 2GB???) DDR3 SDRAM ("sbram" as for SouthBridge RAM) Samsung K4B2G1646E-BCK0, the main serial flash MX25L25635FMI-10G, SATA bridge MB86C311B, GbLAN controller 88EC060-NN82, etc. See also File:PS4_-_SAA-001_diagram.png

Southbridge revisions

There are three major hardware revisions, named Aeolia, Belize and Baikal.

See also Aeolia.

Southbridge revisions per chassis

Model (chassis)	Motherboards	Southbridge Codename	Southbridge Labeling
D1000	All CVN	Aeolia	CXD90025G
1000	All SAA	Aeolia	CXD90025G
1100	All SAB	Aeolia	CXD90025G
1200	All SAC	Belize	CXD90036G
2000	All SAD	Belize	CXD90036G
D7000	All HAC	Belize	CXD90036G
2100	Some SAE	Belize 2	CXD90046GG
7000	All NVA	Belize 2	CXD90046GG
2200	Some SAE, all SAF	Baikal	CXD90042GG
7100	All NVB	Baikal	CXD90042GG
7200	All NVG	Baikal	CXD90042GG

Motherboards per southbridge revisions

Southbridge Codename	Southbridge Labeling	Motherboards
Aeolia	CXD90025G	CVN-K12 SAA-001 SAB-001
Belize	CXD90036G	HAC-001 NVA-001 SAC-001 SAD-001 SAD-003
Belize 2	CXD90046GG	NVA-001 NVB-003 NVG-001 SAE-001 SAF-005
Baikal	CXD90042GG	NVB-004 SAD-002 SAE-002 SAE-003 SAE-004 SAF-003 SAF-004