USB Host Communicating with a Teensy 4.1

[AndrewFernie]

I have two Teensy 4.1, one of which is acting as a G-code sender and the other is a grblHAL controller. I would like to use USB Host mode on the sender to communicate with the controller via USB serial.

While I can use the Teensy G-code sender to connect to a standard grbl controller running on an Arduino Uno, I cannot get it to communicate with a Teensy 4.1 running grblHAL. The Teensy running grblHAL connects with no problem to a PC.

I went through the USBHost_t36 library I am using for the USB host code and noticed that it currently handles the VID/PID in the code below extracted from serial.cpp

/************************************************************/
//  Define mapping VID/PID - to Serial Device type.
/************************************************************/
USBSerial::product_vendor_mapping_t USBSerial::pid_vid_mapping[] = {
	// FTDI mappings. 
	{0x0403, 0x6001, USBSerial::FTDI},

	// PL2303
	{0x67B,0x2303, USBSerial::PL2303}, 

	// CH341
	{0x4348, 0x5523, USBSerial::CH341 },
	{0x1a86, 0x7523, USBSerial::CH341 },
	{0x1a86, 0x5523, USBSerial::CH341 },

	// Silex CP210...
	{0x10c4, 0xea60, USBSerial::CP210X }
};

When I plug the Teensy into my PC and check which device has been connected I find VID=16C0 and PID=0483, so, not supported by the USBHost_t36 library.

Any suggestions for adapting USBHost_t36 to support communication with a Teensy 4.1?

Thank you,
Andrew