FTDI transmit, add partial packet output

USBHost_t36.h

 	USBDriverTimer(USBDriver *d) : driver(d) { }
 	void init(USBDriver *d) { driver = d; };
 	void start(uint32_t microseconds);
+	void stop();
 	void *pointer;
 	uint32_t integer;
 	uint32_t started_micros; // testing only
 class USBSerial: public USBDriver, public Stream {
 public:
 	enum { BUFFER_SIZE = 390 }; // must hold at least 6 max size packets, plus 2 extra bytes
-	USBSerial(USBHost &host) { init(); }
+	USBSerial(USBHost &host) : txtimer(this) { init(); }
 	void begin(uint32_t baud, uint32_t format=0);
 	void end(void);
 	virtual int available(void);
 	virtual bool claim(Device_t *device, int type, const uint8_t *descriptors, uint32_t len);
 	virtual void control(const Transfer_t *transfer);
 	virtual void disconnect();
+	virtual void timer_event(USBDriverTimer *whichTimer);
 private:
 	static void rx_callback(const Transfer_t *transfer);
 	static void tx_callback(const Transfer_t *transfer);
 private:
 	Pipe_t mypipes[3] __attribute__ ((aligned(32)));
 	Transfer_t mytransfers[7] __attribute__ ((aligned(32)));
+	USBDriverTimer txtimer;
 	uint32_t bigbuffer[(BUFFER_SIZE+3)/4];
 	setup_t setup;
 	uint8_t setupdata[8];

ehci.cpp

 	list->next = this;
 }
 
+void USBDriverTimer::stop()
+{
+	__disable_irq();
+	if (active_timers) {
+		if (active_timers == this) {
+			USBHS_GPTIMER1CTL = 0;
+			if (next) {
+				uint32_t usec_til_next = USBHS_GPTIMER1CTL & 0xFFFFFF;
+				usec_til_next += next->usec;
+				next->usec = usec_til_next;
+				USBHS_GPTIMER1LD = usec_til_next;
+				USBHS_GPTIMER1CTL = USBHS_GPTIMERCTL_RST | USBHS_GPTIMERCTL_RUN;
+				next->prev = NULL;
+				active_timers = next;
+			} else {
+				active_timers = NULL;
+			}
+		} else {
+			for (USBDriverTimer *t = active_timers->next; t; t = t->next) {
+				if (t == this) {
+					t->prev->next = t->next;
+					if (t->next) {
+						t->next->usec += t->usec;
+						t->next->prev = t->prev;
+					}
+					break;
+				}
+			}
+		}
+	}
+	__enable_irq();
+}
+
 
 static uint32_t QH_capabilities1(uint32_t nak_count_reload, uint32_t control_endpoint_flag,
 	uint32_t max_packet_length, uint32_t head_of_list, uint32_t data_toggle_control,

serial.cpp

 #define print   USBHost::print
 #define println USBHost::println
 
+
+/************************************************************/
+//  Initialization and claiming of devices & interfaces
+/************************************************************/
+
 void USBSerial::init()
 {
 	contribute_Pipes(mypipes, sizeof(mypipes)/sizeof(Pipe_t));
 }
 
 
+/************************************************************/
+//  Control Transfer For Configuration
+/************************************************************/
 
 
 void USBSerial::control(const Transfer_t *transfer)
 	}
 }
 
+
+/************************************************************/
+//  Interrupt-based Data Movement
+/************************************************************/
+
 void USBSerial::rx_callback(const Transfer_t *transfer)
 {
 	if (!transfer->driver) return;
 		println("tx2:");
 		txstate &= 0xFD;
 	}
-	// TODO: anything need to be done with latency timeout?
 }
 
 
+void USBSerial::timer_event(USBDriverTimer *whichTimer)
+{
+	println("txtimer");
+	uint32_t count;
+	uint32_t head = txhead;
+	uint32_t tail = txtail;
+	if (head == tail) {
+		return; // nothing to transmit
+	} else if (head > tail) {
+		count = head - tail;
+	} else {
+		count = txsize + head - tail;
+	}
+	uint8_t *p;
+	if ((txstate & 0x01) == 0) {
+		p = tx1;
+		txstate |= 0x01;
+	} else if ((txstate & 0x02) == 0) {
+		p = tx2;
+		txstate |= 0x02;
+	} else {
+		txtimer.start(1200);
+		return; // no outgoing buffers available, try again later
+	}
+	if (++tail >= txsize) tail = 0;
+	uint32_t n = txsize - tail;
+	if (n > count) n = count;
+	memcpy(p, txbuf + tail, n);
+	if (n >= count) {
+		tail += n - 1;
+		if (tail >= txsize) tail = 0;
+	} else {
+		uint32_t len = count - n;
+		memcpy(p + n, txbuf, len);
+		tail = len - 1;
+	}
+	txtail = tail;
+	queue_Data_Transfer(txpipe, p, count, this);
+}
 
 
 
-
+/************************************************************/
+//  User Functions - must disable USBHQ IRQ for EHCI access
+/************************************************************/
 
 void USBSerial::begin(uint32_t baud, uint32_t format)
 {
 
 void USBSerial::end(void)
 {
+	// TODO: lower DTR
 }
 
 int USBSerial::available(void)
 			return 1;
 		}
 	}
-	// TODO: otherwise set a latency timer to transmit partial packet
+	// otherwise, set a latency timer to later transmit partial packet
+	txtimer.stop();
+	txtimer.start(3500);
 	NVIC_ENABLE_IRQ(IRQ_USBHS);
 	return 1;
 }
 
 
 
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