firmeware: clean up usb driver

1 files changed, 20 insertions, 38 deletions

diff --git a/firmware/usbdrv/asmcommon.inc b/firmware/usbdrv/asmcommon.inc
index 19fb3d3..5f269af 100644
--- a/firmware/usbdrv/asmcommon.inc
+++ b/firmware/usbdrv/asmcommon.inc
@@ -5,6 +5,9 @@
  * Tabsize: 4
  * Copyright: (c) 2007 by OBJECTIVE DEVELOPMENT Software GmbH
  * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ *
+ * Modified to an interrupt-less driver for micronucleus V2. (c) 2014 T. Bo"scke
+ *
  */
 
 /* Do not link this file! Link usbdrvasm.S instead, which includes the
@@ -82,41 +85,22 @@ se0:
 ;   rjmp    handleSetupOrOut    ; fallthrough
 
 ;Setup and Out are followed by a data packet two bit times (16 cycles) after
-;the end of SE0. The sync code allows up to 40 cycles delay (5 bit times) from 
-;the start of  the sync pattern until the first bit is sampled. That's a total of 56 cycles.
-
-; TB 2014-01-04
-; USB1.1 spec defines a minimum of two bit times and a maximum of 6.5 bit times
-; between Setup/Out and Data. We have to make sure we also cover the upper end
-; of the spec on a 16Mhz device. 
-;
-;           Bit times       µs      cycles @12Mhz    cycles @16 Mhz
-; minimum     2             1.33      16                21
-; maximum     6.5           4.33      52                69
-; meas. Win7  3             2.04      24                32
-; meas. Linux 5             3.5       40                53
+;the end of SE0. The sync code allows up to 40 cycles delay from the start of
+;the sync pattern until the first bit is sampled. That's a total of 56 cycles.
 ;
-; Currently it is only checked at cycle 46..49 if another interrupt occured. This is
-; too early for 16 Mhz and the interrupt will not catch the data packet if it is later
-; than 4 bit times.
-; 
-; fix: Introduce additional delay with timeout for the 16 und 16.5 Mhz version. 
-; The 12 and 12.8 Mhz versions are still fine without as the maximum delay is less than 46 cycles.
-; 
-; The total time until the next packet may not exceed 2 (min) +5 (sync tolerance) bit times 
-;     = 75 cycles @16Mhz to
-; The minimum time to cover max. timeout is 6.5 bit times = 70 cycles @16 Mhz
-;  
-; Additional delay = 70-46=24 cycles. -> going to 21 cycles to be safe.
+;TB 2014-02-02 
+;The interrupt-less driver always has to wait for the next packet at this point 
+;or usbpoll() will get confused.
 
 handleSetupOrOut:               ;[32]
-; Delay, see above
-#if (F_CPU >= 16000000)
-    ldi     YL, 7     ;
-USBdelay:
-    subi    YL, 1      
-    brne    USBdelay   
-#endif
+    ldi     YL,10               ; Time out
+waitForData:
+    USB_LOAD_PENDING(x2)        ;[xx]
+    sbrc    x2, USB_INTR_PENDING_BIT;[xx] check whether data is already arriving
+    rjmp    storeTokenAndReturn
+    dec     YL
+    brne     waitForData
+
 #if USB_CFG_IMPLEMENT_FN_WRITEOUT   /* if we have data for endpoint != 0, set usbCurrentTok to address */
     andi    x3, 0xf             ;[32]
     breq    storeTokenAndReturn ;[33]
@@ -126,17 +110,15 @@ storeTokenAndReturn:
     sts     usbCurrentTok, token;[35]
 doReturn:
     POP_STANDARD                ;[37] 12...16 cycles
-
     USB_LOAD_PENDING(YL)        ;[49]
     sbrc    YL, USB_INTR_PENDING_BIT;[50] check whether data is already arriving
     rjmp    waitForJ            ;[51] save the pops and pushes -- a new interrupt is already pending
 sofError:
     POP_RETI                    ;macro call
     
-    CBI   PORTB,0
+    ret                         ;02-02-2014 not called from INT in micronucleus.
 ;    reti
-    ret
-    
+
 handleData:
 #if USB_CFG_CHECK_CRC
     CRC_CLEANUP_AND_CHECK       ; jumps to ignorePacket if CRC error
@@ -157,8 +139,8 @@ handleData:
     sts     usbRxLen, cnt       ;[28] store received data, swap buffers
     sts     usbRxToken, shift   ;[30]
     
-; Micronculeus v2 needs no double buffer due to in-order processing
-; TB 2014-01-04     
+; Microncleus V2 does not need double buffering due to in-order processing of USB-rx
+; TB 2014-01-04
 ;    lds     x2, usbInputBufOffset;[32] swap buffers
 ;    ldi     cnt, USB_BUFSIZE    ;[34]
 ;    sub     cnt, x2             ;[35]