From c799eccf0b9aca0ee9a88651afd887756d0aa30c Mon Sep 17 00:00:00 2001
From: Christian Pointner <equinox@spreadspace.org>
Date: Wed, 30 May 2012 03:02:35 +0000
Subject: cleaned usb-spi example

git-svn-id: https://svn.spreadspace.org/avr/trunk@46 aa12f405-d877-488e-9caf-2d797e2a1cc7
---
 usb-spi/usb-spi.c | 65 +++++++------------------------------------------------
 1 file changed, 8 insertions(+), 57 deletions(-)

(limited to 'usb-spi/usb-spi.c')

diff --git a/usb-spi/usb-spi.c b/usb-spi/usb-spi.c
index 950f4f3..513df00 100644
--- a/usb-spi/usb-spi.c
+++ b/usb-spi/usb-spi.c
@@ -21,7 +21,7 @@
  */
 
 
-/* this is more or less the same as the LUFA example Project USBtoSerial and
+/* this is based on the LUFA example Project USBtoSerial
    this is their LICENSE Header */
 
 /*
@@ -93,18 +93,9 @@ void EVENT_USB_Device_Disconnect(void);
 void EVENT_USB_Device_ConfigurationChanged(void);
 void EVENT_USB_Device_ControlRequest(void);
 
-void EVENT_CDC_Device_LineEncodingChanged(USB_ClassInfo_CDC_Device_t* const CDCInterfaceInfo);
-
-/** Circular buffer to hold data from the host before it is sent to the device via the serial port. */
 static RingBuffer_t USBtoSPI_Buffer;
-
-/** Underlying data buffer for \ref USBtoSPI_Buffer, where the stored bytes are located. */
 static uint8_t      USBtoSPI_Buffer_Data[128];
-
-/** Circular buffer to hold data from the serial port before it is sent to the host. */
 static RingBuffer_t SPItoUSB_Buffer;
-
-/** Underlying data buffer for \ref SPItoUSB_Buffer, where the stored bytes are located. */
 static uint8_t      SPItoUSB_Buffer_Data[128];
 
 /** LUFA CDC Class driver interface configuration and state information. This structure is
@@ -132,9 +123,6 @@ USB_ClassInfo_CDC_Device_t VirtualSerial_CDC_Interface =
   };
 
 
-/** Main program entry point. This routine contains the overall program flow, including initial
- *  setup of all components and the main program loop.
- */
 int main(void)
 {
   SetupHardware();
@@ -143,17 +131,12 @@ int main(void)
   RingBuffer_InitBuffer(&SPItoUSB_Buffer, SPItoUSB_Buffer_Data, sizeof(SPItoUSB_Buffer_Data));
 
   sei();
-  
-  for (;;)
-  {
 
+  for (;;) {
     int16_t BytesReceived = CDC_Device_BytesReceived(&VirtualSerial_CDC_Interface);
-    while(BytesReceived > 0)
-    {
-      if(!(RingBuffer_IsFull(&USBtoSPI_Buffer)))
-      {
+    while(BytesReceived > 0) {
+      if(!(RingBuffer_IsFull(&USBtoSPI_Buffer))) {
         int16_t ReceivedByte = CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface);
-            /* Read bytes from the USB OUT endpoint into the SPI transmit buffer */
         if (!(ReceivedByte < 0))
           RingBuffer_Insert(&USBtoSPI_Buffer, ReceivedByte);
 
@@ -161,29 +144,18 @@ int main(void)
       }
     }
 
-    /* Check if the SPI receive buffer flush timer has expired or the buffer is nearly full */
     uint16_t BufferCount = RingBuffer_GetCount(&SPItoUSB_Buffer);
-    if ((TIFR0 & (1 << TOV0)) || (BufferCount > (uint8_t)(sizeof(SPItoUSB_Buffer_Data) * .75)))
-    {
-      /* Clear flush timer expiry flag */
+    if ((TIFR0 & (1 << TOV0)) || (BufferCount > (uint8_t)(sizeof(SPItoUSB_Buffer_Data) * .75))) {
       TIFR0 |= (1 << TOV0);
-
-      /* Read bytes from the SPI receive buffer into the USB IN endpoint */
-      while (BufferCount--)
-      {
-        /* Try to send the next byte of data to the host, abort if there is an error without dequeuing */
+      while (BufferCount--) {
         if (CDC_Device_SendByte(&VirtualSerial_CDC_Interface,
                                 RingBuffer_Peek(&SPItoUSB_Buffer)) != ENDPOINT_READYWAIT_NoError)
-        {
           break;
-        }
 
-        /* Dequeue the already sent byte from the buffer now we have confirmed that no transmission error occurred */
         RingBuffer_Remove(&SPItoUSB_Buffer);
       }
     }
 
-    /* Load the next byte from the SPI transmit buffer into the SPI Interface */
     if (!(RingBuffer_IsEmpty(&USBtoSPI_Buffer)))
       SPI_TransferBuffer();
 
@@ -192,10 +164,8 @@ int main(void)
   }
 }
 
-/** Configures the board hardware and chip peripherals for the demo's functionality. */
 void SetupHardware(void)
 {
-  /* Disable watchdog if enabled by bootloader/fuses */
   MCUSR &= ~(1 << WDRF);
   wdt_disable();
 
@@ -203,11 +173,8 @@ void SetupHardware(void)
   led_init();
   USB_Init();
 
-  /* Start the flush timer so that overflows occur rapidly to push received bytes to the USB interface */
   TCCR0B = (1 << CS02);
 
-  /* Initialize SPI Interfaces 
-     configure Direction of SS / PB0 , MOSI and SCLK as Output */
   SPI_DDR = (1<<MOSI)|(1<<SCK)|(1<<CS);
   SPI_PORT = (1<<CS);
   SPCR = (1<<SPE)|(1<<MSTR);
@@ -220,7 +187,7 @@ void SPI_TransferBuffer()
   while(!(RingBuffer_IsEmpty(&USBtoSPI_Buffer))) {
     SPDR = RingBuffer_Remove(&USBtoSPI_Buffer);
     while(!(SPSR & (1<<SPIF)));
-    
+
     uint8_t ReceivedByte = SPDR;
     if (USB_DeviceState == DEVICE_STATE_Configured) {
       RingBuffer_Insert(&SPItoUSB_Buffer, ReceivedByte);
@@ -228,23 +195,20 @@ void SPI_TransferBuffer()
         break;
     }
   }
-  
+
   SPI_PORT |= (1<<CS);
 }
 
-/** Event handler for the library USB Connection event. */
 void EVENT_USB_Device_Connect(void)
 {
   led_on();
 }
 
-/** Event handler for the library USB Disconnection event. */
 void EVENT_USB_Device_Disconnect(void)
 {
   led_off();
 }
 
-/** Event handler for the library USB Configuration Changed event. */
 void EVENT_USB_Device_ConfigurationChanged(void)
 {
   bool ConfigSuccess = true;
@@ -256,20 +220,7 @@ void EVENT_USB_Device_ConfigurationChanged(void)
   led_toggle();
 }
 
-/** Event handler for the library USB Control Request reception event. */
 void EVENT_USB_Device_ControlRequest(void)
 {
   CDC_Device_ProcessControlRequest(&VirtualSerial_CDC_Interface);
 }
-
-/** Event handler for the CDC Class driver Line Encoding Changed event.
- *
- *  \param[in] CDCInterfaceInfo  Pointer to the CDC class interface configuration structure being referenced
- */
-void EVENT_CDC_Device_LineEncodingChanged(USB_ClassInfo_CDC_Device_t* const CDCInterfaceInfo)
-{
-/*
- * Ignore config change for SPI
- */
-}
-
-- 
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