Bootstrap - Digi ConnectCore 8X Hardware Reference Manual

The ConnectCore 8X System-on-module
RTC connection without coin cell charger
RTC connection with coin cell charger
Note This hardware configuration has been validated with the Panasonic DB2J31400L diode, which
has a low reverse leakage current (300nA) that is ideal for this low-power mode application.

Bootstrap

The ConnectCore 8X module can be configured to boot from different devices and interfaces as
determined by the Boot ROM. The configuration of the booting process of the CPU is done through the
SCU (System Control Unit) boot mode.
The BOOT_MODE is initialized by the SCU at the rising edge of POR_B, when it latched the SCU_
BOOT_MODE lines. Once these lines are sampled, the subsequent state does not affect the content of
the BOOT_MODE, which is tracked by the SCU.
The following table describes the eight boot modes that are supported by the ConnectCore 8X
module:
BOOT_MODE
[3]
0
ConnectCore® 8X System-on-Module Hardware Reference Manual
BOOT_MODE BOOT_MODE
[2] [1]
0 0
BOOT_MODE
[0] Boot mode
0 Boot from eFuses
Bootstrap
20