diff --git a/src/platforms/common/usb_serial.c b/src/platforms/common/usb_serial.c
index 0b8bab0..5c363dc 100644
--- a/src/platforms/common/usb_serial.c
+++ b/src/platforms/common/usb_serial.c
@@ -211,6 +211,20 @@ size_t debug_uart_write(const char *buf, const size_t len)
 	return len;
 }
 
+void usbuart_run(void)
+{
+	nvic_disable_irq(USB_IRQ);
+
+	/* Enable LED */
+	usbuart_set_led_state(RX_LED_ACT, true);
+
+	/* Try to send a packet if usb is idle */
+	if (rx_usb_trfr_cplt)
+		usbuart_send_rx_packet();
+
+	nvic_enable_irq(USB_IRQ);
+}
+
 /*
  * newlib defines _write as a weak link'd function for user code to override.
  *
diff --git a/src/platforms/common/usbuart.h b/src/platforms/common/usbuart.h
index 7a4d523..fa0b91b 100644
--- a/src/platforms/common/usbuart.h
+++ b/src/platforms/common/usbuart.h
@@ -27,8 +27,13 @@
 void usbuart_usb_out_cb(usbd_device *dev, uint8_t ep);
 void usbuart_usb_in_cb(usbd_device *dev, uint8_t ep);
 
+void usbuart_set_led_state(uint8_t ledn, bool state);
+void usbuart_send_rx_packet(void);
 void usbuart_run(void);
 
+#define TX_LED_ACT (1 << 0)
+#define RX_LED_ACT (1 << 1)
+
 /* F072 with st_usbfs_v2_usb_drive drops characters at the 64 byte boundary!*/
 #if !defined(USART_DMA_BUF_SIZE)
 # define USART_DMA_BUF_SIZE 128
@@ -36,6 +41,9 @@ void usbuart_run(void);
 #define RX_FIFO_SIZE (USART_DMA_BUF_SIZE)
 #define TX_BUF_SIZE (USART_DMA_BUF_SIZE)
 
+extern bool tx_trfr_cplt;
+extern bool rx_usb_trfr_cplt;
+
 #ifdef ENABLE_DEBUG
 /* Debug Fifo buffer with space for copy fn overrun */
 extern char usb_dbg_buf[RX_FIFO_SIZE + sizeof(uint64_t)];
diff --git a/src/platforms/stm32/usbuart.c b/src/platforms/stm32/usbuart.c
index d295ded..fe014a3 100644
--- a/src/platforms/stm32/usbuart.c
+++ b/src/platforms/stm32/usbuart.c
@@ -49,9 +49,6 @@
 #define DMA_CGIF DMA_IFCR_CGIF_BIT
 #endif
 
-#define TX_LED_ACT (1 << 0)
-#define RX_LED_ACT (1 << 1)
-
 /* TX double buffer */
 static uint8_t buf_tx[TX_BUF_SIZE * 2];
 /* Active buffer part idx */
@@ -59,13 +56,13 @@ static uint8_t buf_tx_act_idx;
 /* Active buffer part used capacity */
 static uint8_t buf_tx_act_sz;
 /* TX transfer complete */
-static bool tx_trfr_cplt = true;
+bool tx_trfr_cplt = true;
 /* RX Fifo buffer with space for copy fn overrun */
 static uint8_t buf_rx[RX_FIFO_SIZE + sizeof(uint64_t)];
 /* RX Fifo out pointer, writes assumed to be atomic */
 static uint8_t buf_rx_out;
 /* RX usb transfer complete */
-static bool rx_usb_trfr_cplt = true;
+bool rx_usb_trfr_cplt = true;
 
 #ifdef ENABLE_DEBUG
 /* Debug Fifo buffer with space for copy fn overrun */
@@ -79,7 +76,7 @@ uint8_t usb_dbg_out;
 /*
  * Update led state atomically respecting RX anb TX states.
  */
-static void usbuart_set_led_state(uint8_t ledn, bool state)
+void usbuart_set_led_state(uint8_t ledn, bool state)
 {
 	CM_ATOMIC_CONTEXT();
 
@@ -265,7 +262,7 @@ void usbuart_usb_out_cb(usbd_device *dev, uint8_t ep)
  * Runs deferred processing for USBUSART RX, draining RX FIFO by sending
  * characters to host PC via CDCACM. Allowed to write to FIFO OUT pointer.
  */
-static void usbuart_send_rx_packet(void)
+void usbuart_send_rx_packet(void)
 {
 	rx_usb_trfr_cplt = false;
 	/* Calculate writing position in the FIFO */
@@ -324,20 +321,6 @@ void usbuart_usb_in_cb(usbd_device *dev, uint8_t ep)
 	usbuart_send_rx_packet();
 }
 
-void usbuart_run(void)
-{
-	nvic_disable_irq(USB_IRQ);
-
-	/* Enable LED */
-	usbuart_set_led_state(RX_LED_ACT, true);
-
-	/* Try to send a packet if usb is idle */
-	if (rx_usb_trfr_cplt)
-		usbuart_send_rx_packet();
-
-	nvic_enable_irq(USB_IRQ);
-}
-
 #if defined(USART_ICR)
 #define USBUSART_ISR_TEMPLATE(USART, DMA_IRQ) do {			\
 	nvic_disable_irq(DMA_IRQ);					\