I modified Daisa's code (refer to USB In MQX) for my project (K60 MCU's UUS connected to an external USB device). I opened two pipes with endpoint 1 and bulk pipe type. I can open pipe and send data successfully, but when I read response I received error 0x81. In details, I received following message (recompile USB host library to enable debug print) when I call _usb_host_recv_data()
_usb_host_new_tr_element malloc failed
_usb_host_get_tr_element error null pipe tr_list
_usb_host_set_up_tr NULL transaction
_usb_host_recv_data transfer queue failed
Can you help me to find the problem?