RawHID tramsit on Teensy 4.0

teensy4/usb.c

 		#if defined(CDC_STATUS_INTERFACE) && defined(CDC_DATA_INTERFACE)
 		usb_serial_configure();
 		#endif
+		#if defined(RAWHID_INTERFACE)
+		usb_rawhid_configure();
+		#endif
 		endpoint0_receive(NULL, 0, 0);
 		return;
 	  case 0x0880: // GET_CONFIGURATION

teensy4/usb_desc.h

   #define RAWHID_INTERFACE      0	// RawHID
   #define RAWHID_TX_ENDPOINT    3
   #define RAWHID_TX_SIZE        64
-  #define RAWHID_TX_INTERVAL    1
+  #define RAWHID_TX_INTERVAL    1	 // TODO: is this ok for 480 Mbit speed
   #define RAWHID_RX_ENDPOINT    4
   #define RAWHID_RX_SIZE        64
-  #define RAWHID_RX_INTERVAL    1
+  #define RAWHID_RX_INTERVAL    1	 // TODO: is this ok for 480 Mbit speed
   #define SEREMU_INTERFACE      1	// Serial emulation
   #define SEREMU_TX_ENDPOINT    1
   #define SEREMU_TX_SIZE        64
-  #define SEREMU_TX_INTERVAL    1
+  #define SEREMU_TX_INTERVAL    1	 // TODO: is this ok for 480 Mbit speed
   #define SEREMU_RX_ENDPOINT    2
   #define SEREMU_RX_SIZE        32
-  #define SEREMU_RX_INTERVAL    2
+  #define SEREMU_RX_INTERVAL    2	 // TODO: is this ok for 480 Mbit speed
   #define ENDPOINT1_CONFIG	ENDPOINT_RECEIVE_UNUSED + ENDPOINT_TRANSMIT_INTERRUPT
   #define ENDPOINT2_CONFIG	ENDPOINT_RECEIVE_INTERRUPT + ENDPOINT_TRANSMIT_UNUSED
   #define ENDPOINT3_CONFIG	ENDPOINT_RECEIVE_UNUSED + ENDPOINT_TRANSMIT_INTERRUPT

teensy4/usb_rawhid.c

 #include <string.h>    // for memcpy()
 //#include "HardwareSerial.h"
 
+#include "debug/printf.h"
+
 #ifdef RAWHID_INTERFACE // defined by usb_dev.h -> usb_desc.h
 
+#define TX_NUM   4
+static transfer_t tx_transfer[TX_NUM] __attribute__ ((used, aligned(32)));
+static uint8_t txbuffer[RAWHID_TX_SIZE * TX_NUM];
+static uint8_t tx_head=0;
+
+extern volatile uint8_t usb_configuration;
+
+static void rx_event(transfer_t *t)
+{
+
+}
+
+void usb_rawhid_configure(void)
+{
+	printf("usb_rawhid_configure\n");
+	memset(tx_transfer, 0, sizeof(tx_transfer));
+	tx_head = 0;
+	usb_config_tx(RAWHID_TX_ENDPOINT, RAWHID_TX_SIZE, 0, NULL);
+	usb_config_rx(RAWHID_RX_ENDPOINT, RAWHID_RX_SIZE, 0, rx_event);
+}
+
 int usb_rawhid_recv(void *buffer, uint32_t timeout)
 {
-	return -1;
+	transfer_t *xfer = tx_transfer + tx_head;
+	uint32_t wait_begin_at = systick_millis_count;
+
+	while (1) {
+		if (!usb_configuration) return -1; // usb not enumerated by host
+		uint32_t status = usb_transfer_status(xfer);
+		if (!(status & 0x80)) break; // transfer descriptor ready
+		if (systick_millis_count - wait_begin_at > timeout) return 0;
+		yield();
+	}
+	uint8_t *txdata = txbuffer + (tx_head * RAWHID_TX_SIZE);
+	memcpy(txdata, buffer, RAWHID_TX_SIZE);
+	usb_prepare_transfer(xfer, txdata, RAWHID_TX_SIZE, 0);
+	usb_transmit(RAWHID_TX_ENDPOINT, xfer);
+	if (++tx_head >= TX_NUM) tx_head = 0;
+	return RAWHID_TX_SIZE;
 }
 
 int usb_rawhid_available(void)

teensy4/usb_rawhid.h

 #ifdef __cplusplus
 extern "C" {
 #endif
+void usb_rawhid_configure(void);
 int usb_rawhid_recv(void *buffer, uint32_t timeout);
 int usb_rawhid_available(void);
 int usb_rawhid_send(const void *buffer, uint32_t timeout);