searched the whole forum for a while now but did not find any related questions.
I would like to use the ATmega32U4 from the Leonardo in Low Speed USB mode but didn’t get it to work. Background is, that with low speed mode there is no need for an external crystal oscillator.
The first test I made was to compile the caterina bootloader with low speed USB mode enabled. To do this I changed the makefile for the bootloader to compile the LUFA library with low speed mode. The bootloader works (the board enumerates as Arduino Leonardo and the LED breathes) but I can’t upload sketches using the Arduino IDE. Always get avrdude error:
Connecting to programmer: .avrdude: Send: . [1b]
avrdude: ser_send(): write error: sorry no info avail
When I flash the full speed bootloader the upload works fine again.
I thought never mind lets try to compile the sketch using low speed USB mode. So I changed the function USBDevice_::attach() in “USBCore.cpp” to enable the low speed mode:
Changed the line: UDCON = 0;
to: UDCON = (1<<LSM);//Low Speed mode
Compiled the test sketch using the arduino IDE and flashed the hex. Now the Leonardo is not detected correctly when plugging in (USB device not recognized).
When I undo the change, compile again and flash the “Full Speed” hex everything works fine again.
What am I missing?
If you need more information please ask me.
I’m using Arduino IDE 1.0.3 on Windows XP.
Thank you in advance for any help.