Hi,
My questions goes regarding the ability to connect USB devices to the Organelle S/M.
The manual tells, that the USB ports could only deliver 0,5 Ampere:
„NOTE: Some MIDI controllers can be powered by their Host’s USB port. The Organelle’s USB ports can only supply a maximum of 0.5A. If your USB device requires more than the Organelle can provide, communication and/or performance issues may arise. If you experience these, please consult your USB device’s manual about power requirements. A powered USB hub or power adapter for external device can resolve these power demands.“
Regarding this topic I found the following:
Starting with the Raspberry Pi model B+, the power supply is significantly more stable, especially via the USB for external devices. With the B+ model, a parameter was also introduced that controls how much power USB devices are allowed to draw from the USB port in total.
By default, the total current from the USB ports is limited to 600mA. This limit is there so that the Raspberry Pi does not become unstable and switch off when a power-hungry USB device is used. Only the USB is then switched off.
In total, the Raspberry Pi is allowed to pass 1.2A (1,200mA) to the USB devices when the limit is lifted. But that only makes sense if the power supply is also powerful enough.
A corresponding boot parameter must be set to increase the current limit from 600 mA to 1,200 mA.
To do this, the file with the boot configuration is opened:
sudo nano /boot/config.txt
Here you enter the following line (old firmware):
safe_mode_gpio=4
Here you enter the following line (current firmware):
max_usb_current=1
Then save and close the file: Ctrl + O, Return, Ctrl + X.
The system must be rebooted for the boot parameter to take effect.
Has anyone some experience with this topic? Since the actual power adapter only delivers 9 Volt and 1 Ampere, I think for this this topic 9 Volt and 2 Ampere would be recommended.