====================================================================================================
SPD mux
====================================================================================================

DIMM_A1 SDA signal traced to U6 pin 1
Destructive testing of failed board (removal of U7 northbridge!) yielded the following information:
U6 S0 <--> U7 W2
U6 S1 <--> U7 W3

Proprietary BIOS enables the SPD during POST with:
S0: LOW
S1: LOW

then temporarily switches to:
S0: LOW
S1: HIGH

then switches to runtime mode with:
S0: HIGH
S1: LOW

After probing with a custom GPIO-flipping tool under Linux the following GPIO mappings were found:
CK804 pin W2 <--> GPIO43
CK804 pin W3 <--> GPIO44

====================================================================================================
W83793 (U46)
====================================================================================================

Sensor mappings:
FRNT_FAN1: FAN3
FRNT_FAN2: FAN4
FRNT_FAN3: FAN5
FRNT_FAN4: FAN6
FRNT_FAN5: FAN9
FRNT_FAN6: FAN10
REAR_FAN1: FAN7
REAR_FAN2: FAN8
REAR_FAN3: FAN11
REAR_FAN4: FAN12

====================================================================================================
Other hardware
====================================================================================================

Power LED (-) is connected to U15 (SuperIO) pin 64 via U4 pins 5,6 and a small MOSFET
ID LED (-) is connected to a ??? via U4 pins 1,2,3,4 and U77 pins 5,6
It appears that setting U15 (SuperIO) pin 88 LOW will override the ID LED and force it ON

RECOVERY2 middle pin is connected to U15 (SuperIO) pin 89
Normal is HIGH, recovery is LOW.

PCIe slot WAKE# connects to U7 pin E23 (PCIE_WAKE#)

CPU_WARN1 is driven by (???) via a simple buffer (U13 pin 10)
MEM_WARN1 is driven by U7 pin AD3 (CPUVDD_EN) via a simple buffer (U101 pin 3)

U7 pin AK3 is disconnected (routed to unpopulated capacitor/resistor)
PU1 pin 37 (VDDPWRGD) drives U7 pin AJ4 (CPU_VLD)
A small MOSFET directly above another small MOSFET directly above the right-hand edge of the PCIe slot drives U7 pin AK5 (HT_VLD)

When > Barcelona CPU installed on PCB rev 1.04G:
U7 pin AK4 (MEM_VLD): HIGH
PU1 pin 37:           LOW
U7 pin AK5:           LOW

HyperTransport 1.2V supply appears to be generated by a linear regulator containing Q191 and downconverting the CK804 1.5V supply
The enable pin appears to be tied to AUX_PANEL pin 1 (+5VSB) via a resistor
Through two MOSFETs the HT supply enable pin is tied to U7 pin AE3 (HTVDD_EN)