asem - Man Page

driver for UPS in ASEM PB1300


asem -h



This man page only documents the hardware-specific features of the asem driver. For information about the core driver, see nutupsdrv(8).

Supported Hardware

The asem driver supports the UPS in ASEM PB1300 embedded PCs. Likely other I2C devices from the same manufacturer will work too, since this is a "custom" charger.

Seems that there are two versions of the charger. Older one is based on Max1667, newer one is a custom solution. Both are on I2C address 0x09. To be compatible with both versions, the driver just reads bit 15 of address 0x13 which yields online/on battery status. Battery monitor is a BQ2060 at address 0x0B.

Extra Arguments

The required parameter for this driver is the I2C bus name:


On the Asem PB1300, this should be /dev/i2c-7 for the i801 SMBUS adapter.

This driver also supports the following optional settings:


Set the low battery threshold to num volts.


Set the high battery threshold to num volts.


This driver is specific to the Linux I2C API, and requires the lm_sensors libi2c-dev or its equivalent to compile.

Beware that the SystemIO memory used by the I2C controller is reserved by ACPI. If only a native I2C driver (e.g. i2c_i801, as of 3.5.X Linux kernels) is available, then you’ll need to relax the ACPI resources check. For example, you can boot with the acpi_enforce_resources=lax option.

Known Issues and Bugs

The driver shutdown function is not implemented, so other arrangements must be made to turn off the UPS.


Giuseppe Corbelli <>

See Also

The core driver


Internet resources

Referenced By

nutupsdrv(8), upsd(8).

04/02/2024 Network UPS Tools 2.8.2 NUT Manual