U4
CXD2973GB
South Bridge
BGA (39x39 pads on CXD2973GB)
I/O south bridge
About this component
The south bridge connects to the Cell over the FlexIO bus and handles all the slower I/O. It also sits between the Cell and the system flash (NAND or NOR), so a damaged south bridge can look like a corrupted-firmware fault. Each board family uses its own part, and the pad layout shrinks from 39x39 on COK-001 to 22x22 on DYN-001. Part variants: CXD2973GB on COK-001 (CECHA/B); CXD2979GB on COK-002 (CECHC/E); CXD2984GB on SEM-001 (CECHG); CXD2984AGB on VER-001 (CECHL/P); CXD9963GB on DYN-001 (CECH-20xx). Later boards not listed on psdevwiki.
What it does on this board
Handles SATA, USB and legacy I/O.
Pinout & readings
No pinout or reference readings yet — these show what each pin does and what a healthy part should measure.