- added usbconfig.h option USB_CFG_CHECK_DATA_TOGGLING

5 files changed, 24 insertions, 3 deletions

diff --git a/usbdrv/Changelog.txt b/usbdrv/Changelog.txt
index c6af6bb..6c1a0d4 100644
--- a/usbdrv/Changelog.txt
+++ b/usbdrv/Changelog.txt
@@ -236,3 +236,4 @@ Scroll down to the bottom to see the most recent changes.
     was not incremented, pointer to length was incremented instead.
   - Added code to command line tool(s) which claims an interface. This code
     is disabled by default, but may be necessary on newer Linux kernels.
+  - Added usbconfig.h option "USB_CFG_CHECK_DATA_TOGGLING".
diff --git a/usbdrv/asmcommon.inc b/usbdrv/asmcommon.inc
index 819c0bd..febfeb0 100644
--- a/usbdrv/asmcommon.inc
+++ b/usbdrv/asmcommon.inc
@@ -103,8 +103,8 @@ sofError:
     reti
 
 handleData:
-    lds     token, usbCurrentTok;[18]
-    tst     token               ;[20]
+    lds     shift, usbCurrentTok;[18]
+    tst     shift               ;[20]
     breq    doReturn            ;[21]
     lds     x2, usbRxLen        ;[22]
     tst     x2                  ;[24]
@@ -113,8 +113,11 @@ handleData:
 ; recognized if usbPoll() was called less frequently than once every 4 ms.
     cpi     cnt, 4              ;[26] zero sized data packets are status phase only -- ignore and ack
     brmi    sendAckAndReti      ;[27] keep rx buffer clean -- we must not NAK next SETUP
+#if USB_CFG_CHECK_DATA_TOGGLING
+    sts     usbCurrentDataToken, token  ; store for checking by C code
+#endif
     sts     usbRxLen, cnt       ;[28] store received data, swap buffers
-    sts     usbRxToken, token   ;[30]
+    sts     usbRxToken, shift   ;[30]
     lds     x2, usbInputBufOffset;[32] swap buffers
     ldi     cnt, USB_BUFSIZE    ;[34]
     sub     cnt, x2             ;[35]
diff --git a/usbdrv/usbconfig-prototype.h b/usbdrv/usbconfig-prototype.h
index eb66b81..035c627 100644
--- a/usbdrv/usbconfig-prototype.h
+++ b/usbdrv/usbconfig-prototype.h
@@ -156,6 +156,14 @@ section at the end of this file).
  * counts SOF packets. This feature requires that the hardware interrupt is
  * connected to D- instead of D+.
  */
+#define USB_CFG_CHECK_DATA_TOGGLING     0
+/* define this macro to 1 if you want to filter out duplicate data packets
+ * sent by the host. Duplicates occur only as a consequence of communication
+ * errors, when the host does not receive an ACK. Please note that you need to
+ * implement the filtering yourself in usbFunctionWriteOut() and
+ * usbFunctionWrite(). Use the global usbCurrentDataToken and a static variable
+ * for each control- and out-endpoint to check for duplicate packets.
+ */
 #define USB_CFG_HAVE_MEASURE_FRAME_LENGTH   0
 /* define this macro to 1 if you want the function usbMeasureFrameLength()
  * compiled in. This function can be used to calibrate the AVR's RC oscillator.
diff --git a/usbdrv/usbdrv.c b/usbdrv/usbdrv.c
index 20e9ad8..eed2d52 100644
--- a/usbdrv/usbdrv.c
+++ b/usbdrv/usbdrv.c
@@ -44,6 +44,9 @@ usbTxStatus_t  usbTxStatus1;
 usbTxStatus_t  usbTxStatus3;
 #   endif
 #endif
+#if USB_CFG_CHECK_DATA_TOGGLING
+uchar       usbCurrentDataToken;/* when we check data toggling to ignore duplicate packets */
+#endif
 
 /* USB status registers / not shared with asm code */
 uchar               *usbMsgPtr;     /* data to transmit next -- ROM or RAM address */
diff --git a/usbdrv/usbdrv.h b/usbdrv/usbdrv.h
index 4769917..e2c08ec 100644
--- a/usbdrv/usbdrv.h
+++ b/usbdrv/usbdrv.h
@@ -339,6 +339,12 @@ extern volatile uchar   usbSofCount;
  * the macro USB_COUNT_SOF is defined to a value != 0.
  */
 #endif
+#if USB_CFG_CHECK_DATA_TOGGLING
+extern uchar    usbCurrentDataToken;
+/* This variable can be checked in usbFunctionWrite() and usbFunctionWriteOut()
+ * to ignore duplicate packets.
+ */
+#endif
 
 #define USB_STRING_DESCRIPTOR_HEADER(stringLength) ((2*(stringLength)+2) | (3<<8))
 /* This macro builds a descriptor header for a string descriptor given the