COMe-bV26 - Rev. 1.0, User Guide
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Features and Interfaces
3.1.
ACPI Power States
ACPI enables the system to power down and save power when not required (suspend) and wake up when required
(resume). The ACPI controls the power states S0-S5, where S0 has the highest priority and S5 the lowest priority.
The COMe-bV26 supports the ACPI 6.0 power states S0, S3, S4 and S5 only.
Not all ACPI defined power states are available.
Systems that support the low-power idle state do not use power states S1.
Table 15: Supported Power States Function
S0
Working state
S3
Suspend to RAM state
S4
Suspend-to-disk/Hibernate
S5
Soft-off state
To power on from states S3, S4 and S5 use:
Power Button
WakeOnLAN (S3, S4)
The OS must support wake up from a USB devices and the carrier board must power the USB
port with the standby voltage.
3.2.
Fast I2C
The internal I2C bus transfer between components on the same module and the external I2C bus transfers between
I2C devices connected on the bus. The fast I2C bus transfers data with transfer rates up to 400 kHz.
To change the I2C bus speed, in the BIOS setup menu select:
Advanced>Miscellaneous>I2C Speed> 400 kHz to 1 kHz
The default speed is 200 kHz.
3.3.
GPIO
The eight GPIO pins are available, with four pins for the in-direction (pin A54 for GPI0, pin A63 for GPI1, pin A67 for GPI2
and pin A85 for GPI3) and four pins for the out-direction (pin A93 for GPO0, pin B54 for GPO1, pin B57 for GPO2 and pin
B63 for GPO3). The type of termination resistor uses sets the direction of the GPIO; where GPIs are terminated with
pull-up resistors and GPOs are terminated with pull-down resistors.
Due to, the fact that both the pull-up and pull-down termination resistors are weak, it is possible to override the
termination resistors using external pull-ups, pull-downs or IOs. Overriding the termination resistors means that the
eight GPIO pins can be considered as bi-directional since there are no restrictions whether you use the available GPIO
pins in the in-direction or out-direction.
