In case of interest: with the R-Pi sitting idle with 'top' load average: 0.00, 0.01, 0.05
No monitor, no video, no USB and no Ethernet devices connected (UART serial port only -see viewtopic.php?f=44&t=9665
Voltage is measured onboard, TP1-TP2. Ambient surface temperature is 27 C, air temp 24 C.
IR thermometer: MicroTemp MT100 cross-checked with thermocouple sensor.
RPi power draw: 318 mA at 5.0 V (1.59 W) Chip temperatures: SoC: 46 C, Eth/USB: 51 C, SD card: 32 C
after this command as root, and waiting 10 minutes for temperature to stabilize
- Code: Select all
echo 1 > /sys/devices/platform/bcm2708_usb/bussuspend
RPi power draw: 182 mA at 5.0 V (0.91 W) Chip temperatures: SoC: 40 C, Eth/USB: 39 C, SD card: 30 C
so the system uses 1.59 W when idle but Eth/USB on, and 0.91 W when Eth/USB shut down, nearly half the power. This could make a difference in some possible use cases, where you want to power up the high-bandwidth link only when needed. Can the Eth/USB system be turned back on after "bussuspend" without doing a full reboot, and if so how? The obvious 'echo 0 > /sys/devices/platform/bcm2708_usb/bussuspend' has no apparent effect- power draw remains 182 mA and no USB device can be mounted.