Kontron COMe Starterkit Eval T2 - Manual (Page 208)

Appendix A: Deprecated Features
The BIOS device shown in Figure 80: LPC Firmware Hub above is a SST SST49LF008A
Firmware Hub in a 32-pin PLCC package. The socket used is a 32-pin PLCC socket, AMP/Tyco
822498-1. This is a surface-mount socket, and PCBs can be laid out such that the socket or the
FWH itself is soldered to the Carrier Board.
The FWH is connected to the system via the LPC interface. Data and address information are
carried on the LPC_AD[0:3] lines. LPC_FRAME# indicates the start of a new frame.
FWH pins 2 (RST#) and 24 (INIT#) reset the FWH. These pins are logically combined together
internally on the FWH, and a low on either pin will reset the FWH.
FWH pins 6, 5, 4, 3, 30 – (FGPI [0:4]) are general-purpose inputs that may be read by system
software. They should be tied to a valid logic level.
FWH pin 7 ( WP#) enables write protection for main block sectors when it is pulled low. If pulled
high, hardware write protection is disabled. FWH pin 8 (TBL# ) enables write protection for the
top block sector when pulled low.
FWH pins 12,11,10, 9 – (ID[0:3]) are ID pins that allow multiple FWH parts (up to 16) to be used.
By convention, in Intel x86-based systems, the boot device is FWH number 0. To boot from the
Carrier Board FWH, the Module BIOS_DISABLE# pin must be low (to disable the Module BIOS)
and the Carrier Board FWH ID[0:3] pins (pins 12,11,10,9) must be low (to enable it as the boot
device). If jumper J27 in Figure 80: LPC Firmware Hub above is installed, the Module BIOS is
disabled, and the Carrier Board FWH may be used as a boot device.
FWH pin 29 configures the FWH into one of two modes: if high, the FWH is in the Programmer
configuration. If low, it is in the firmware hub configuration. For normal operation on a Carrier
Board, this pin should be tied low.
FWH pin 31 is the clock input. The clock source is the LPC_CLK signal from the COM Express
Module.
FWH pin 2 – RST# supports Chip Reset. The LPC_RESET# signal from the COM Express
Module drives the reset. The pin functions the same as INIT# above.
PICMG ® COM Express ® Carrier Board Design Guide Rev. 2.0 / December 6, 2013
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