fish

15 files changed, 450 insertions, 164 deletions

diff --git a/Makefile.rules b/Makefile.rules
index 685caad..b67e343 100644
--- a/Makefile.rules
+++ b/Makefile.rules
@@ -80,7 +80,7 @@ SCRIPT_DIR	= $(OPENCM3_DIR)/scripts
 
 CFLAGS		+= -Os -g
 CFLAGS		+= -Wextra -Wimplicit-function-declaration
-CFLAGS		+= -Wredundant-decls -Wmissing-prototypes -Wstrict-prototypes
+CFLAGS		+= -Wmissing-prototypes -Wstrict-prototypes
 CFLAGS		+= -fno-common -ffunction-sections -fdata-sections
 
 ###############################################################################
@@ -179,7 +179,7 @@ fish:
 
 clean:
 	@#printf "  CLEAN\n"
-	$(Q)$(RM) *.o *.d *.elf *.bin *.hex *.srec *.list *.map
+	$(Q)$(RM) *.o *.d *.elf *.bin *.hex *.srec *.list *.map *~
 
 stylecheck: $(STYLECHECKFILES:=.stylecheck)
 styleclean: $(STYLECHECKFILES:=.styleclean)
diff --git a/src/Makefile b/src/Makefile
index 1a9f2b2..f7f445a 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -23,7 +23,7 @@ PROG=kvm
 V=1
 default: ${PROG}.elf
 
-CSRCS=dfu.c mouse.c keyboard.c main.c usb.c  tablet.c uart.c
+CSRCS=dfu.c mouse.c keyboard.c main.c usb.c  tablet.c usart.c kvm.c ring.c
 
 
 BINARY = ${PROG}
diff --git a/src/dfu.c b/src/dfu.c
index 56420ad..e9de46f 100644
--- a/src/dfu.c
+++ b/src/dfu.c
@@ -3,56 +3,58 @@
 #ifdef INCLUDE_DFU_INTERFACE
 
 const struct usb_dfu_descriptor dfu_function = {
-	.bLength = sizeof(struct usb_dfu_descriptor),
-	.bDescriptorType = DFU_FUNCTIONAL,
-	.bmAttributes = USB_DFU_CAN_DOWNLOAD | USB_DFU_WILL_DETACH,
-	.wDetachTimeout = 255,
-	.wTransferSize = 1024,
-	.bcdDFUVersion = 0x011A,
+  .bLength = sizeof (struct usb_dfu_descriptor),
+  .bDescriptorType = DFU_FUNCTIONAL,
+  .bmAttributes = USB_DFU_CAN_DOWNLOAD | USB_DFU_WILL_DETACH,
+  .wDetachTimeout = 255,
+  .wTransferSize = 1024,
+  .bcdDFUVersion = 0x011A,
 };
 
 const struct usb_interface_descriptor dfu_iface = {
-	.bLength = USB_DT_INTERFACE_SIZE,
-	.bDescriptorType = USB_DT_INTERFACE,
-	.bInterfaceNumber = 3,
-	.bAlternateSetting = 0,
-	.bNumEndpoints = 0,
-	.bInterfaceClass = 0xFE,
-	.bInterfaceSubClass = 1,
-	.bInterfaceProtocol = 1,
-	.iInterface = 0,
-
-	.extra = &dfu_function,
-	.extralen = sizeof(dfu_function),
+  .bLength = USB_DT_INTERFACE_SIZE,
+  .bDescriptorType = USB_DT_INTERFACE,
+  .bInterfaceNumber = 3,
+  .bAlternateSetting = 0,
+  .bNumEndpoints = 0,
+  .bInterfaceClass = 0xFE,
+  .bInterfaceSubClass = 1,
+  .bInterfaceProtocol = 1,
+  .iInterface = 0,
+
+  .extra = &dfu_function,
+  .extralen = sizeof (dfu_function),
 };
 
 
-static void dfu_detach_complete(usbd_device *usbd_dev, struct usb_setup_data *req)
+static void
+dfu_detach_complete (usbd_device * usbd_dev, struct usb_setup_data *req)
 {
-	(void)req;
-	(void)usbd_dev;
-
-	gpio_set_mode(GPIOA, GPIO_MODE_INPUT, 0, GPIO15);
-	gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_2_MHZ,
-		      GPIO_CNF_OUTPUT_PUSHPULL, GPIO10);
-	gpio_set(GPIOA, GPIO10);
-	scb_reset_core();
+  (void) req;
+  (void) usbd_dev;
+
+  gpio_set_mode (GPIOA, GPIO_MODE_INPUT, 0, GPIO15);
+  gpio_set_mode (GPIOA, GPIO_MODE_OUTPUT_2_MHZ,
+                 GPIO_CNF_OUTPUT_PUSHPULL, GPIO10);
+  gpio_set (GPIOA, GPIO10);
+  scb_reset_core ();
 }
 
-int dfu_control_request(usbd_device *usbd_dev, struct usb_setup_data *req, uint8_t **buf, uint16_t *len,
-			void (**complete)(usbd_device *usbd_dev, struct usb_setup_data *req))
+int
+dfu_control_request (usbd_device * usbd_dev, struct usb_setup_data *req,
+                     uint8_t ** buf, uint16_t * len,
+                     void (**complete) (usbd_device * usbd_dev,
+                                        struct usb_setup_data * req))
 {
-	(void)buf;
-	(void)len;
-	(void)usbd_dev;
+  (void) buf;
+  (void) len;
+  (void) usbd_dev;
 
-	if ((req->bmRequestType != 0x21) || (req->bRequest != DFU_DETACH))
-		return 0; /* Only accept class request. */
+  if ((req->bmRequestType != 0x21) || (req->bRequest != DFU_DETACH))
+    return 0;                   /* Only accept class request. */
 
-	*complete = dfu_detach_complete;
+  *complete = dfu_detach_complete;
 
-	return 1;
+  return 1;
 }
 #endif
-
-
diff --git a/src/keyboard.c b/src/keyboard.c
index e4ed7e2..e9046a3 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -114,7 +114,8 @@ const struct usb_interface_descriptor keyboard_iface = {
 };
 
 
-void keyboard_get_descriptor(uint8_t **buf,uint16_t *len)
+void
+keyboard_get_descriptor (uint8_t ** buf, uint16_t * len)
 {
 
   /* Handle the HID report descriptor. */
@@ -126,12 +127,12 @@ void
 keyboard_test (void)
 {
   static int c = 0;
-  uint8_t buf[8] = { 0, 0, 0, 0 ,0,0,0,0};
+  uint8_t buf[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
 
 
-  buf[0]=(c>> 1) & 7;
+  buf[0] = (c >> 1) & 7;
 
-  buf[2]= (c&1) ? 12:0;
+  buf[2] = (c & 1) ? 12 : 0;
 
   c++;
 
diff --git a/src/kvm.c b/src/kvm.c
new file mode 100644
index 0000000..f5e65c8
--- /dev/null
+++ b/src/kvm.c
@@ -0,0 +1,91 @@
+#include "project.h"
+
+
+static enum
+{
+  STATE_SYNC = 0,
+  STATE_ADDR = 1,
+  STATE_ENDPOINT = 2,
+  STATE_LEN = 3,
+  STATE_DATA = 4,
+} state = STATE_SYNC;
+
+
+static uint8_t buf[16];
+static int addr;
+static int endpoint;
+static unsigned int len;
+static unsigned int ptr;
+
+void
+kvm_dispatch (void)
+{
+#if 0
+          printf
+            ("Addr %d, Write to ep %x, %d bytes %02x %02x %02x %02x ...\r\n",
+             addr, endpoint, len, buf[0], buf[1], buf[2], buf[3]);
+#endif
+
+ if(len)
+  usbd_ep_write_packet (usbd_dev, endpoint, buf, len);
+}
+
+void
+kvm_recv (uint8_t d)
+{
+//  printf ("S%d V0x%02x\r\n", state, d);
+
+  if (state == STATE_ADDR)
+    {
+      addr = d;
+      usart_queue (d - 1);
+      state = STATE_ENDPOINT;
+      return;
+    }
+  else
+    {
+      usart_queue (d);
+    }
+
+
+  switch (state)
+    {
+    case STATE_SYNC:
+      if (d != 0x5a)
+          break;
+      state = STATE_ADDR;
+      break;
+    case STATE_ENDPOINT:
+      endpoint = d;
+      if ((endpoint < 0x81) || (endpoint > 0x83))
+        {
+          state = STATE_SYNC;
+        }
+      else
+        {
+          state = STATE_LEN;
+        }
+      break;
+    case STATE_LEN:
+      len = d;
+      ptr = 0;
+      if (len > sizeof (buf))
+        {
+          state = STATE_SYNC;
+        }
+      else
+        {
+          state = STATE_DATA;
+        }
+      break;
+    case STATE_DATA:
+      buf[ptr++] = d;
+      if (ptr >= len)
+        {
+          if (!addr)
+            kvm_dispatch ();
+          state = STATE_SYNC;
+        }
+      break;
+    }
+}
diff --git a/src/main.c b/src/main.c
index 6b13a82..3058108 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,49 +1,55 @@
 #include "project.h"
 
-void sys_tick_handler(void)
+void
+sys_tick_handler (void)
 {
-	keyboard_test();
-	mouse_test();
-	tablet_test();
+#if 0
+  printf ("fish\r\n");
+  keyboard_test ();
+  mouse_test ();
+  tablet_test ();
+#endif
 }
 
-int main(void)
+int
+main (void)
 {
-	int i;
+  int i;
 
 
-	rcc_clock_setup_in_hsi_out_48mhz();
-	rcc_periph_clock_enable(RCC_GPIOC);
-        rcc_periph_clock_enable(RCC_GPIOA);
-        rcc_periph_clock_enable(RCC_AFIO);
-        rcc_periph_clock_enable(RCC_USART1);
+  rcc_clock_setup_in_hsi_out_48mhz ();
+  rcc_periph_clock_enable (RCC_GPIOC);
+  rcc_periph_clock_enable (RCC_GPIOA);
+  rcc_periph_clock_enable (RCC_AFIO);
+  rcc_periph_clock_enable (RCC_USART1);
 
 
-	uart_init();
+  usart_init ();
 
-	usb_init();
+  usb_init ();
 
-	systick_set_clocksource(STK_CSR_CLKSOURCE_AHB_DIV8);
-	/* 48MHz / 8 = > 6Mhz */
-	systick_set_reload(3000000);
-	/* 6MHz / 3000000 => 2Hz */
+  systick_set_clocksource (STK_CSR_CLKSOURCE_AHB_DIV8);
+  /* 48MHz / 8 = > 6Mhz */
+  systick_set_reload (3000000);
+  /* 6MHz / 3000000 => 2Hz */
 
-	systick_interrupt_enable();
-	systick_counter_enable();
+  systick_interrupt_enable ();
+  systick_counter_enable ();
 
-	gpio_set(GPIOC, GPIO11);
-	gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_2_MHZ,
-		      GPIO_CNF_OUTPUT_PUSHPULL, GPIO11);
+  gpio_set (GPIOC, GPIO11);
+  gpio_set_mode (GPIOC, GPIO_MODE_OUTPUT_2_MHZ,
+                 GPIO_CNF_OUTPUT_PUSHPULL, GPIO11);
 
-	
 
-	for (i = 0; i < 0x80000; i++)
-		__asm__("nop");
 
-	gpio_clear(GPIOC, GPIO11);
+  for (i = 0; i < 0x80000; i++)
+    __asm__ ("nop");
 
-	usb_run();
+  gpio_clear (GPIOC, GPIO11);
 
-	return 0;
-}
+  printf ("Hello world\r\n");
+
+  usb_run ();
 
+  return 0;
+}
diff --git a/src/mouse.c b/src/mouse.c
index acb4166..6e0a207 100644
--- a/src/mouse.c
+++ b/src/mouse.c
@@ -88,7 +88,8 @@ const struct usb_interface_descriptor mouse_iface = {
 };
 
 
-void mouse_get_descriptor(uint8_t **buf,uint16_t *len)
+void
+mouse_get_descriptor (uint8_t ** buf, uint16_t * len)
 {
 
   /* Handle the HID report descriptor. */
@@ -104,9 +105,9 @@ mouse_test (void)
 
   buf[0] = c & 7;
 
-  buf[1] = c &8 ? -1:1;
-  buf[2] = c &16 ? -1:1;
-  buf[3] = c &32 ? -1:1;
+  buf[1] = c & 8 ? -1 : 1;
+  buf[2] = c & 16 ? -1 : 1;
+  buf[3] = c & 32 ? -1 : 1;
 
   c++;
 
diff --git a/src/project.h b/src/project.h
index de86ece..0323569 100644
--- a/src/project.h
+++ b/src/project.h
@@ -1,7 +1,9 @@
 #include <stdlib.h>
 #include <libopencm3/stm32/rcc.h>
 #include <libopencm3/stm32/gpio.h>
+#include <libopencm3/stm32/usart.h>
 #include <libopencm3/cm3/systick.h>
+#include <libopencm3/cm3/nvic.h>
 #include <libopencm3/usb/usbd.h>
 #include <libopencm3/usb/hid.h>
 
@@ -13,5 +15,9 @@
 #include <libopencm3/usb/dfu.h>
 #endif
 
+#include <stdio.h>
+#include <errno.h>
+
+#include "ring.h"
 
 #include "prototypes.h"
diff --git a/src/prototypes.h b/src/prototypes.h
index 9b4d2c9..0e971df 100644
--- a/src/prototypes.h
+++ b/src/prototypes.h
@@ -28,5 +28,16 @@ extern const struct usb_endpoint_descriptor tablet_endpoint;
 extern const struct usb_interface_descriptor tablet_iface;
 extern void tablet_get_descriptor(uint8_t **buf, uint16_t *len);
 extern void tablet_test(void);
-/* uart.c */
-extern void uart_init(void);
+/* usart.c */
+extern void usart1_isr(void);
+extern int _write(int file, char *ptr, int len);
+extern void usart_queue(uint8_t d);
+extern void usart_init(void);
+/* kvm.c */
+extern void kvm_dispatch(void);
+extern void kvm_recv(uint8_t d);
+/* ring.c */
+extern void ring_init(ring_t *r, uint8_t *buf, size_t len);
+extern int ring_write_byte(ring_t *r, uint8_t c);
+extern int ring_read_byte(ring_t *r, uint8_t *c);
+extern int ring_write(ring_t *r, uint8_t *buf, size_t len);
diff --git a/src/ring.c b/src/ring.c
new file mode 100644
index 0000000..4f38e44
--- /dev/null
+++ b/src/ring.c
@@ -0,0 +1,61 @@
+#include "project.h"
+
+
+static inline size_t
+ring_next (ring_t * r, size_t p)
+{
+  p++;
+  if (p >= r->size)
+    p -= r->size;
+  return p;
+}
+
+void
+ring_init (ring_t * r, uint8_t * buf, size_t len)
+{
+  r->data = buf;
+  r->size = len;
+  r->write = 0;
+  r->read = 0;
+}
+
+int
+ring_write_byte (ring_t * r, uint8_t c)
+{
+  size_t n = ring_next (r, r->write);
+
+  if (n == r->read)
+    return -1;
+
+  r->data[r->write] = c;
+  r->write = n;
+
+  return 0;
+}
+
+
+int
+ring_read_byte (ring_t * r, uint8_t * c)
+{
+  size_t n = ring_next (r, r->read);
+
+  if (r->read == r->write)
+    return -1;
+
+  *c = r->data[r->read];
+  r->read = n;
+
+  return 0;
+}
+
+int
+ring_write (ring_t * r, uint8_t * buf, size_t len)
+{
+  while (len--)
+    {
+      if (ring_write_byte (r, *(buf++)))
+        return -1;
+    }
+
+  return 0;
+}
diff --git a/src/ring.h b/src/ring.h
new file mode 100644
index 0000000..4e3a22c
--- /dev/null
+++ b/src/ring.h
@@ -0,0 +1,9 @@
+typedef struct ring
+{
+  uint8_t *data;
+  size_t size;
+  size_t write;
+  size_t read;
+} ring_t;
+
+
diff --git a/src/tablet.c b/src/tablet.c
index 87d2f2a..1073b37 100644
--- a/src/tablet.c
+++ b/src/tablet.c
@@ -1,50 +1,50 @@
 #include "project.h"
 
 static const uint8_t tablet_report_descriptor[] = {
-    0x05, 0x01,                    // USAGE_PAGE (Generic Desktop)
-    0x09, 0x02,                    // USAGE (Mouse)
-    0xa1, 0x01,                    // COLLECTION (Application)
-    0x09, 0x01,                    //   USAGE (Pointer)
-    0xa1, 0x00,                    //   COLLECTION (Physical)
-    0x05, 0x01,                    //     USAGE_PAGE (Generic Desktop)
-    0x09, 0x30,                    //     USAGE (X)
-    0x09, 0x31,                    //     USAGE (Y)
-    0x15, 0x00,                    //     LOGICAL_MINIMUM (0)
-    0x26, 0xff, 0x7f,              //     LOGICAL_MAXIMUM (32767)
-    0x75, 0x10,                    //     REPORT_SIZE (16)
-    0x95, 0x02,                    //     REPORT_COUNT (2)
-    0x81, 0x02,                    //     INPUT (Data,Var,Abs)
-    0x05, 0x01,                    //     USAGE_PAGE (Generic Desktop)
-    0x09, 0x38,                    //     USAGE (Wheel)
-    0x15, 0x81,                    //     LOGICAL_MINIMUM (-127)
-    0x25, 0x7f,                    //     LOGICAL_MAXIMUM (127)
-    0x75, 0x08,                    //     REPORT_SIZE (8)
-    0x95, 0x01,                    //     REPORT_COUNT (1)
-    0x81, 0x06,                    //     INPUT (Data,Var,Rel)
-    0x05, 0x09,                    //     USAGE_PAGE (Button)
-    0x19, 0x01,                    //     USAGE_MINIMUM (Button 1)
-    0x29, 0x03,                    //     USAGE_MAXIMUM (Button 3)
-    0x15, 0x00,                    //     LOGICAL_MINIMUM (0)
-    0x25, 0x01,                    //     LOGICAL_MAXIMUM (1)
-    0x95, 0x03,                    //     REPORT_COUNT (3)
-    0x75, 0x01,                    //     REPORT_SIZE (1)
-    0x81, 0x02,                    //     INPUT (Data,Var,Abs)
-    0x95, 0x01,                    //     REPORT_COUNT (1)
-    0x75, 0x05,                    //     REPORT_SIZE (5)
-    0x81, 0x01,                    //     INPUT (Cnst,Ary,Abs)
-    0xc0,                          //   END_COLLECTION
-    0x09, 0x3c,                    //   USAGE (Button 60)
-    0x06, 0x00, 0xff,              //   USAGE_PAGE (Vendor Defined Page 1)
-    0x09, 0x01,                    //   USAGE (Vendor Usage 1)
-    0x15, 0x00,                    //   LOGICAL_MINIMUM (0)
-    0x25, 0x01,                    //   LOGICAL_MAXIMUM (1)
-    0x75, 0x01,                    //   REPORT_SIZE (1)
-    0x95, 0x02,                    //   REPORT_COUNT (2)
-    0xb1, 0x22,                    //   FEATURE (Data,Var,Abs,NPrf)
-    0x75, 0x06,                    //   REPORT_SIZE (6)
-    0x95, 0x01,                    //   REPORT_COUNT (1)
-    0xb1, 0x01,                    //   FEATURE (Cnst,Ary,Abs)
-    0xc0                           // END_COLLECTION
+  0x05, 0x01,                   // USAGE_PAGE (Generic Desktop)
+  0x09, 0x02,                   // USAGE (Mouse)
+  0xa1, 0x01,                   // COLLECTION (Application)
+  0x09, 0x01,                   //   USAGE (Pointer)
+  0xa1, 0x00,                   //   COLLECTION (Physical)
+  0x05, 0x01,                   //     USAGE_PAGE (Generic Desktop)
+  0x09, 0x30,                   //     USAGE (X)
+  0x09, 0x31,                   //     USAGE (Y)
+  0x15, 0x00,                   //     LOGICAL_MINIMUM (0)
+  0x26, 0xff, 0x7f,             //     LOGICAL_MAXIMUM (32767)
+  0x75, 0x10,                   //     REPORT_SIZE (16)
+  0x95, 0x02,                   //     REPORT_COUNT (2)
+  0x81, 0x02,                   //     INPUT (Data,Var,Abs)
+  0x05, 0x01,                   //     USAGE_PAGE (Generic Desktop)
+  0x09, 0x38,                   //     USAGE (Wheel)
+  0x15, 0x81,                   //     LOGICAL_MINIMUM (-127)
+  0x25, 0x7f,                   //     LOGICAL_MAXIMUM (127)
+  0x75, 0x08,                   //     REPORT_SIZE (8)
+  0x95, 0x01,                   //     REPORT_COUNT (1)
+  0x81, 0x06,                   //     INPUT (Data,Var,Rel)
+  0x05, 0x09,                   //     USAGE_PAGE (Button)
+  0x19, 0x01,                   //     USAGE_MINIMUM (Button 1)
+  0x29, 0x03,                   //     USAGE_MAXIMUM (Button 3)
+  0x15, 0x00,                   //     LOGICAL_MINIMUM (0)
+  0x25, 0x01,                   //     LOGICAL_MAXIMUM (1)
+  0x95, 0x03,                   //     REPORT_COUNT (3)
+  0x75, 0x01,                   //     REPORT_SIZE (1)
+  0x81, 0x02,                   //     INPUT (Data,Var,Abs)
+  0x95, 0x01,                   //     REPORT_COUNT (1)
+  0x75, 0x05,                   //     REPORT_SIZE (5)
+  0x81, 0x01,                   //     INPUT (Cnst,Ary,Abs)
+  0xc0,                         //   END_COLLECTION
+  0x09, 0x3c,                   //   USAGE (Button 60)
+  0x06, 0x00, 0xff,             //   USAGE_PAGE (Vendor Defined Page 1)
+  0x09, 0x01,                   //   USAGE (Vendor Usage 1)
+  0x15, 0x00,                   //   LOGICAL_MINIMUM (0)
+  0x25, 0x01,                   //   LOGICAL_MAXIMUM (1)
+  0x75, 0x01,                   //   REPORT_SIZE (1)
+  0x95, 0x02,                   //   REPORT_COUNT (2)
+  0xb1, 0x22,                   //   FEATURE (Data,Var,Abs,NPrf)
+  0x75, 0x06,                   //   REPORT_SIZE (6)
+  0x95, 0x01,                   //   REPORT_COUNT (1)
+  0xb1, 0x01,                   //   FEATURE (Cnst,Ary,Abs)
+  0xc0                          // END_COLLECTION
 };
 
 static const struct
@@ -59,8 +59,8 @@ static const struct
 {
   .hid_descriptor =
   {
-  .bLength = sizeof (tablet_function),.bDescriptorType = USB_DT_HID,.bcdHID =
-      0x0100,.bCountryCode = 0,.bNumDescriptors = 1,}
+  .bLength = sizeof (tablet_function),.bDescriptorType =
+      USB_DT_HID,.bcdHID = 0x0100,.bCountryCode = 0,.bNumDescriptors = 1,}
   ,.hid_report =
   {
   .bReportDescriptorType = USB_DT_REPORT,.wDescriptorLength =
@@ -94,7 +94,8 @@ const struct usb_interface_descriptor tablet_iface = {
 };
 
 
-void tablet_get_descriptor(uint8_t **buf,uint16_t *len)
+void
+tablet_get_descriptor (uint8_t ** buf, uint16_t * len)
 {
 
   /* Handle the HID report descriptor. */
@@ -106,14 +107,14 @@ void
 tablet_test (void)
 {
   static int c = 0;
-  uint8_t buf[6] = { 0, 0, 0, 0,0 };
+  uint8_t buf[6] = { 0, 0, 0, 0, 0 };
 
-  buf[0]=c & 0xff;
-  buf[1]=(c &0x7fff) >> 8;
-  buf[2]=(32767 -(c &0x7fff)) & 0xff;
-  buf[3]=(32767 -(c & 0x7fff)) >> 8;
-  buf[4]=(c&8 ) ? -1:1;
-  buf[5]=c;
+  buf[0] = c & 0xff;
+  buf[1] = (c & 0x7fff) >> 8;
+  buf[2] = (32767 - (c & 0x7fff)) & 0xff;
+  buf[3] = (32767 - (c & 0x7fff)) >> 8;
+  buf[4] = (c & 8) ? -1 : 1;
+  buf[5] = c;
 
   c++;
 
diff --git a/src/uart.c b/src/uart.c
deleted file mode 100644
index 70a6334..0000000
--- a/src/uart.c
+++ /dev/null
@@ -1,7 +0,0 @@
-#include "project.h"
-
-
-
-void uart_init(void)
-{
-}
diff --git a/src/usart.c b/src/usart.c
new file mode 100644
index 0000000..b0ea2a4
--- /dev/null
+++ b/src/usart.c
@@ -0,0 +1,104 @@
+#include "project.h"
+
+#define BUFFER_SIZE 256
+
+static ring_t output_ring;
+static uint8_t output_ring_buf[BUFFER_SIZE];
+
+void
+usart1_isr (void)
+{
+  uint8_t data;
+
+  /* Check if we were called because of RXNE. */
+  if (((USART_CR1 (USART1) & USART_CR1_RXNEIE) != 0) &&
+      ((USART_SR (USART1) & USART_SR_RXNE) != 0))
+    {
+
+      /* Retrieve the data from the peripheral. */
+      data = usart_recv (USART1);
+
+      kvm_recv (data);
+    }
+
+  /* Check if we were called because of TXE. */
+  if (((USART_CR1 (USART1) & USART_CR1_TXEIE) != 0) &&
+      ((USART_SR (USART1) & USART_SR_TXE) != 0))
+    {
+
+      if (ring_read_byte (&output_ring, &data))
+        {
+          /*No more data, Disable the TXE interrupt, it's no longer needed. */
+          USART_CR1 (USART1) &= ~USART_CR1_TXEIE;
+        }
+      else
+        {
+          usart_send (USART1, data);
+        }
+    }
+
+}
+
+int
+_write (int file, char *ptr, int len)
+{
+  int ret;
+
+  if (file == 1)
+    {
+      ret = ring_write (&output_ring, (uint8_t *) ptr, len);
+
+      if (ret < 0)
+        ret = -ret;
+
+      USART_CR1 (USART1) |= USART_CR1_TXEIE;
+      return ret;
+    }
+
+  errno = EIO;
+  return -1;
+}
+
+void
+usart_queue (uint8_t d)
+{
+  ring_write_byte(&output_ring,d);
+  USART_CR1 (USART1) |= USART_CR1_TXEIE;
+
+#if 0
+  printf ("0x%02x ", d);
+  fflush (stdout);
+#endif
+}
+
+
+void
+usart_init (void)
+{
+  ring_init (&output_ring, output_ring_buf, sizeof (output_ring_buf));
+
+  /* Enable the USART1 interrupt. */
+  nvic_enable_irq (NVIC_USART1_IRQ);
+
+  /* Setup GPIO pin GPIO_USART1_RE_TX on GPIO port B for transmit. */
+  gpio_set_mode (GPIOA, GPIO_MODE_OUTPUT_50_MHZ,
+                 GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART1_TX);
+
+  /* Setup GPIO pin GPIO_USART1_RE_RX on GPIO port B for receive. */
+  gpio_set_mode (GPIOA, GPIO_MODE_INPUT,
+                 GPIO_CNF_INPUT_FLOAT, GPIO_USART1_RX);
+
+  /* Setup UART parameters. */
+  usart_set_baudrate (USART1, 38400);
+  usart_set_databits (USART1, 8);
+  usart_set_stopbits (USART1, USART_STOPBITS_1);
+  usart_set_parity (USART1, USART_PARITY_NONE);
+  usart_set_flow_control (USART1, USART_FLOWCONTROL_NONE);
+  usart_set_mode (USART1, USART_MODE_TX_RX);
+
+  /* Enable USART1 Receive interrupt. */
+  USART_CR1 (USART1) |= USART_CR1_RXNEIE;
+
+  /* Finally enable the USART. */
+  usart_enable (USART1);
+}
diff --git a/src/usb.c b/src/usb.c
index b004c78..f796162 100644
--- a/src/usb.c
+++ b/src/usb.c
@@ -18,25 +18,25 @@ const struct usb_device_descriptor dev = {
   .bNumConfigurations = 1,
 };
 
-const struct usb_interface ifaces[] = { 
-					{
-                                             .num_altsetting = 1,
-                                             .altsetting = &keyboard_iface,
-					},
-					{
-                                         .num_altsetting = 1,
-                                         .altsetting = &mouse_iface,
-                                         }, 
-					{
-                                         .num_altsetting = 1,
-                                         .altsetting = &tablet_iface,
-                                         }, 
+const struct usb_interface ifaces[] = {
+  {
+   .num_altsetting = 1,
+   .altsetting = &keyboard_iface,
+   },
+  {
+   .num_altsetting = 1,
+   .altsetting = &mouse_iface,
+   },
+  {
+   .num_altsetting = 1,
+   .altsetting = &tablet_iface,
+   },
 #ifdef INCLUDE_DFU_INTERFACE
-                                             {
-                                                 .num_altsetting = 1,
-                                                 .altsetting = &dfu_iface,
+  {
+   .num_altsetting = 1,
+   .altsetting = &dfu_iface,
 #endif
-                                                 }
+   }
 };
 
 const struct usb_config_descriptor config = {
@@ -84,14 +84,14 @@ usb_control_request (usbd_device * usbd_dev, struct usb_setup_data *req,
   switch (req->wIndex)
     {
     case 0:
-        keyboard_get_descriptor(buf,len);
-	return 1;
+      keyboard_get_descriptor (buf, len);
+      return 1;
     case 1:
-        mouse_get_descriptor(buf,len);
-	return 1;
+      mouse_get_descriptor (buf, len);
+      return 1;
     case 2:
-        tablet_get_descriptor(buf,len);
-	return 1;
+      tablet_get_descriptor (buf, len);
+      return 1;
     }
 
   *len = 0;