cExpress-TL User’s Guide
PICMG COM.0 R3.0
Page 62
Copyright © 2021 ADLINK Technology, Inc.
5.6.
BIOS Boot Select
The module has two BIOS chips (BOM option) and BIOS operation can be configured to "PICMG" and dual-BIOS "Failsafe" modes using BIOS Select and
Mode Configuration Switch, Pin 2.
Setting the module to PICMG mode will configure the BIOS chips on the module as SPI0 and SPI1. In PICMG mode, a BIOS chip cannot be placed in the
SPI0 slot on the carrier.
In dual-BIOS Failsafe mode, both BIOS chips on the module are configured as SPI1. Only one of the two is connected to the SPI bus at any given time. In
case of failure of the primary SPI1 BIOS, the system will reboot and switch to the secondary SPI1 BIOS on the module. In Failsafe mode, the SPI0 BIOS
socket on the carrier can be populated.
In either mode, BIOS Select and Mode Configuration Switch Pin 1 is used to select whether to boot from SPI0 or SPI1.
Mode
Pin 1
Pin 2
Boot from SPI0 (default)
On
-
Boot from SPI1
Off
-
Set BIOS to PICMG mode
(default)
-
On
Set BIOS to Failsafe BIOS mode
-
Off
