CDC Notification Endpoint, so we can send CTS/DSR/DCD/RI.

src/arduino/Adafruit_USBD_CDC.cpp

@@ -170,6 +170,50 @@ int Adafruit_USBD_CDC::dtr(void) {
   return tud_cdc_n_connected(_instance);
 }
 
+bool Adafruit_USBD_CDC::rts(void) {
+  return tud_cdc_n_get_line_state(_instance) & CDC_CONTROL_LINE_STATE_RTS;
+}
+
+bool Adafruit_USBD_CDC::cts(void) {
+  return tud_cdc_n_get_serial_state(_instance).cts;
+}
+
+bool Adafruit_USBD_CDC::dsr(void) {
+  return tud_cdc_n_get_serial_state(_instance).dsr;
+}
+
+bool Adafruit_USBD_CDC::dcd(void) {
+  return tud_cdc_n_get_serial_state(_instance).dcd;
+}
+
+bool Adafruit_USBD_CDC::ri(void) {
+  return tud_cdc_n_get_serial_state(_instance).ri;
+}
+
+void Adafruit_USBD_CDC::cts(bool c) {
+  cdc_serial_state_t serial_state = tud_cdc_n_get_serial_state(_instance);
+  serial_state.cts = c;
+  tud_cdc_n_set_serial_state(_instance, serial_state);
+}
+
+void Adafruit_USBD_CDC::dsr(bool c) {
+  cdc_serial_state_t serial_state = tud_cdc_n_get_serial_state(_instance);
+  serial_state.dsr = c;
+  tud_cdc_n_set_serial_state(_instance, serial_state);
+}
+
+void Adafruit_USBD_CDC::dcd(bool c) {
+  cdc_serial_state_t serial_state = tud_cdc_n_get_serial_state(_instance);
+  serial_state.dcd = c;
+  tud_cdc_n_set_serial_state(_instance, serial_state);
+}
+
+void Adafruit_USBD_CDC::ri(bool c) {
+  cdc_serial_state_t serial_state = tud_cdc_n_get_serial_state(_instance);
+  serial_state.ri = c;
+  tud_cdc_n_set_serial_state(_instance, serial_state);
+}
+
 Adafruit_USBD_CDC::operator bool() {
   if (!isValid()) {
     return false;

src/arduino/Adafruit_USBD_CDC.h

@@ -59,7 +59,20 @@ class Adafruit_USBD_CDC : public Stream, public Adafruit_USBD_Interface {
   uint8_t stopbits(void);
   uint8_t paritytype(void);
   uint8_t numbits(void);
-  int dtr(void);
+
+  // Flow control bit getters.
+  int dtr(void); // pre-existing, I don't want to change the return type.
+  bool rts(void);
+  bool cts(void);
+  bool dsr(void);
+  bool dcd(void);
+  bool ri(void);
+
+  // Flow control bit setters.
+  void cts(bool c);
+  void dsr(bool c);
+  void dcd(bool c);
+  void ri(bool c);
 
   // Stream API
   virtual int available(void);

src/class/cdc/cdc.h

@@ -412,6 +412,48 @@ typedef struct TU_ATTR_PACKED
 
 TU_VERIFY_STATIC(sizeof(cdc_line_control_state_t) == 2, "size is not correct");
 
+//--------------------------------------------------------------------+
+// Notifications
+//--------------------------------------------------------------------+
+
+typedef struct TU_ATTR_PACKED {
+  uint16_t dcd         :1;
+  uint16_t dsr         :1;
+  uint16_t break_err   :1;
+  uint16_t ri          :1;
+  uint16_t frame_err   :1;
+  uint16_t parity_err  :1;
+  uint16_t overrun_err :1;
+  uint16_t cts         :1;  // https://community.st.com/t5/stm32-mcus-products/cts-signal-on-usb-cdc/td-p/325800
+  uint16_t             :8;
+} cdc_serial_state_t;
+
+TU_VERIFY_STATIC(sizeof(cdc_serial_state_t) == 2, "size is not correct");
+
+// Add more notifications here.  PSTN120.pdf, Section 6.5
+typedef struct TU_ATTR_PACKED {
+  tusb_notification_t header;
+  union {
+    cdc_serial_state_t serial_state;
+    // Add more Notification "Data" payloads here as more are implemented.
+  };
+} cdc_notify_struct_t;
+
+TU_VERIFY_STATIC(sizeof(cdc_notify_struct_t) == 10, "size is not correct");
+
+tu_static const cdc_notify_struct_t cdc_notify_serial_status = {
+  .header = {
+    .bmRequestType_bit = {
+      .recipient = TUSB_REQ_RCPT_INTERFACE,
+      .type = TUSB_REQ_TYPE_CLASS,
+      .direction = TUSB_DIR_IN,
+    },
+    .bNotification = CDC_NOTIF_SERIAL_STATE,
+    .wValue = 0,
+    .wLength = sizeof(cdc_serial_state_t),
+  }
+};
+
 TU_ATTR_PACKED_END  // End of all packed definitions
 TU_ATTR_BIT_FIELD_ORDER_END
 

src/class/cdc/cdc_device.c

@@ -59,6 +59,10 @@ typedef struct {
   // Bit 0:  DTR (Data Terminal Ready), Bit 1: RTS (Request to Send)
   uint8_t line_state;
 
+  // Notify host of flow control bits: CTS, DSR, DCD, RI, and some error flags.
+  cdc_serial_state_t serial_state;
+  bool serial_state_changed;
+
   /*------------- From this point, data is not cleared by bus reset -------------*/
   char wanted_char;
   TU_ATTR_ALIGNED(4) cdc_line_coding_t line_coding;
@@ -76,6 +80,7 @@ typedef struct {
   // Endpoint Transfer buffer
   CFG_TUSB_MEM_ALIGN uint8_t epout_buf[CFG_TUD_CDC_EP_BUFSIZE];
   CFG_TUSB_MEM_ALIGN uint8_t epin_buf[CFG_TUD_CDC_EP_BUFSIZE];
+  CFG_TUSB_MEM_ALIGN cdc_notify_struct_t epnotif_buf;
 } cdcd_interface_t;
 
 #define ITF_MEM_RESET_SIZE   offsetof(cdcd_interface_t, wanted_char)
@@ -138,6 +143,18 @@ uint8_t tud_cdc_n_get_line_state(uint8_t itf) {
   return _cdcd_itf[itf].line_state;
 }
 
+cdc_serial_state_t tud_cdc_n_get_serial_state(uint8_t itf) {
+  return _cdcd_itf[itf].serial_state;
+}
+
+void tud_cdc_n_set_serial_state(uint8_t itf, cdc_serial_state_t serial_state) {
+  if (memcmp(&(_cdcd_itf[itf].serial_state), &serial_state, sizeof(serial_state)) != 0) {
+    TU_LOG_DRV("  Serial State Changed: %x -> %x\r\n", _cdcd_itf[itf].serial_state, serial_state);
+    _cdcd_itf[itf].serial_state_changed = true;
+  }
+  _cdcd_itf[itf].serial_state = serial_state;
+}
+
 void tud_cdc_n_get_line_coding(uint8_t itf, cdc_line_coding_t* coding) {
   (*coding) = _cdcd_itf[itf].line_coding;
 }
@@ -326,10 +343,13 @@ uint16_t cdcd_open(uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint1
 
   if (TUSB_DESC_ENDPOINT == tu_desc_type(p_desc)) {
     // notification endpoint
-    tusb_desc_endpoint_t const* desc_ep = (tusb_desc_endpoint_t const*) p_desc;
+    tusb_desc_endpoint_t desc_ep = *(tusb_desc_endpoint_t const*) p_desc;
+    TU_LOG_DRV("  Interval before: %d\r\n", desc_ep.bInterval);
+
+    desc_ep.bInterval = 1;  // Query every frame, 1ms at Full Speed.
 
-    TU_ASSERT(usbd_edpt_open(rhport, desc_ep), 0);
-    p_cdc->ep_notif = desc_ep->bEndpointAddress;
+    TU_ASSERT(usbd_edpt_open(rhport, &desc_ep), 0);
+    p_cdc->ep_notif = desc_ep.bEndpointAddress;
 
     drv_len += tu_desc_len(p_desc);
     p_desc = tu_desc_next(p_desc);
@@ -437,12 +457,13 @@ bool cdcd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint32_
   // Identify which interface to use
   for (itf = 0; itf < CFG_TUD_CDC; itf++) {
     p_cdc = &_cdcd_itf[itf];
-    if ((ep_addr == p_cdc->ep_out) || (ep_addr == p_cdc->ep_in)) break;
+    if ((ep_addr == p_cdc->ep_out) || (ep_addr == p_cdc->ep_in) || (ep_addr == p_cdc->ep_notif)) break;
   }
   TU_ASSERT(itf < CFG_TUD_CDC);
 
   // Received new data
   if (ep_addr == p_cdc->ep_out) {
+    TU_LOG_DRV("  XFer Out\r\n");
     tu_fifo_write_n(&p_cdc->rx_ff, p_cdc->epout_buf, (uint16_t) xferred_bytes);
 
     // Check for wanted char and invoke callback if needed
@@ -465,6 +486,7 @@ bool cdcd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint32_
   // Note: This will cause incorrect baudrate set in line coding.
   //       Though maybe the baudrate is not really important !!!
   if (ep_addr == p_cdc->ep_in) {
+    TU_LOG_DRV("  XFer In\r\n");
     // invoke transmit callback to possibly refill tx fifo
     if (tud_cdc_tx_complete_cb) tud_cdc_tx_complete_cb(itf);
 
@@ -479,7 +501,30 @@ bool cdcd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint32_
     }
   }
 
-  // nothing to do with notif endpoint for now
+  // Notifications
+  if (ep_addr == p_cdc->ep_notif) {
+    TU_LOG_DRV("  XFer Notification\r\n");
+    uint8_t const rhport = 0;
+
+    // SERIAL_STATE notification. Send flow control signals.
+    if (p_cdc->serial_state_changed) {
+      p_cdc->serial_state_changed = false;
+
+      // Build the notification
+      p_cdc->epnotif_buf = cdc_notify_serial_status;
+      p_cdc->epnotif_buf.header.wIndex = p_cdc->itf_num;
+      p_cdc->epnotif_buf.serial_state = p_cdc->serial_state;
+
+      // claim endpoint
+      TU_VERIFY(usbd_edpt_claim(rhport, p_cdc->ep_notif), 0);
+
+      // Send notification
+      return usbd_edpt_xfer(rhport, p_cdc->ep_notif, (uint8_t *) &(p_cdc->epnotif_buf), sizeof(p_cdc->epnotif_buf));
+    }
+    else {
+      // Send a NAK?
+    }
+  }
 
   return true;
 }

src/class/cdc/cdc_device.h

@@ -70,6 +70,12 @@ bool tud_cdc_n_connected(uint8_t itf);
 // Get current line state. Bit 0:  DTR (Data Terminal Ready), Bit 1: RTS (Request to Send)
 uint8_t tud_cdc_n_get_line_state(uint8_t itf);
 
+// Get current serial state.
+cdc_serial_state_t tud_cdc_n_get_serial_state(uint8_t itf);
+
+// Set current serial state.
+void tud_cdc_n_set_serial_state(uint8_t itf, cdc_serial_state_t ser_state);
+
 // Get current line encoding: bit rate, stop bits parity etc ..
 void tud_cdc_n_get_line_coding(uint8_t itf, cdc_line_coding_t* coding);
 
@@ -132,6 +138,14 @@ TU_ATTR_ALWAYS_INLINE static inline uint8_t tud_cdc_get_line_state(void) {
   return tud_cdc_n_get_line_state(0);
 }
 
+TU_ATTR_ALWAYS_INLINE static inline cdc_serial_state_t tud_cdc_get_serial_state(void) {
+  return tud_cdc_n_get_serial_state(0);
+}
+
+TU_ATTR_ALWAYS_INLINE static inline void tud_cdc_set_serial_state(cdc_serial_state_t ser_state) {
+  return tud_cdc_n_set_serial_state(0, ser_state);
+}
+
 TU_ATTR_ALWAYS_INLINE static inline void tud_cdc_get_line_coding(cdc_line_coding_t* coding) {
   tud_cdc_n_get_line_coding(0, coding);
 }

src/common/tusb_types.h

@@ -491,6 +491,27 @@ typedef struct TU_ATTR_PACKED {
 
 TU_VERIFY_STATIC( sizeof(tusb_control_request_t) == 8, "size is not correct");
 
+
+typedef struct TU_ATTR_PACKED {
+  union {
+    struct TU_ATTR_PACKED {
+      uint8_t recipient :  5; ///< Recipient type tusb_request_recipient_t.
+      uint8_t type      :  2; ///< Request type tusb_request_type_t.
+      uint8_t direction :  1; ///< Direction type. tusb_dir_t
+    } bmRequestType_bit;
+
+    uint8_t bmRequestType;
+  };
+
+  uint8_t bNotification;
+  uint16_t wValue;
+  uint16_t wIndex;
+  uint16_t wLength;
+} tusb_notification_t;
+
+TU_VERIFY_STATIC( sizeof(tusb_notification_t) == 8, "size is not correct");
+
+
 TU_ATTR_PACKED_END  // End of all packed definitions
 TU_ATTR_BIT_FIELD_ORDER_END