- use timeout in waitForJ

7 files changed, 44 insertions, 20 deletions

diff --git a/usbdrv/Changelog.txt b/usbdrv/Changelog.txt
index 339bca6..9d6844d 100644
--- a/usbdrv/Changelog.txt
+++ b/usbdrv/Changelog.txt
@@ -248,3 +248,4 @@ Scroll down to the bottom to see the most recent changes.
     This accounts for the higher clock rates we now support.
   - Added a module for 12.8 MHz RC oscillator with PLL in receiver loop.
   - Added hook to SOF code so that oscillator can be tuned to USB frame clock.
+  - Added timeout to waitForJ loop. Helps preventing unexpected hangs.
diff --git a/usbdrv/usbdrvasm12.inc b/usbdrv/usbdrvasm12.inc
index d9da1dc..f891ab6 100644
--- a/usbdrv/usbdrvasm12.inc
+++ b/usbdrv/usbdrvasm12.inc
@@ -48,10 +48,14 @@ USB_INTR_VECTOR:
 ;----------------------------------------------------------------------------
 ;sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
 ;sync up with J to K edge during sync pattern -- use fastest possible loops
-;first part has no timeout because it waits for IDLE or SE1 (== disconnected)
+;The first part waits at most 1 bit long since we must be in sync pattern.
+;YL is guarenteed to be < 0x80 because I flag is clear. When we jump to
+;waitForJ, ensure that this prerequisite is met.
 waitForJ:
-    sbis    USBIN, USBMINUS ;1 [40] wait for D- == 1
-    rjmp    waitForJ        ;2
+    sbic    USBIN, USBMINUS
+    rjmp    waitForK
+    inc     YL
+    brne    waitForJ        ; just make sure we have ANY timeout
 waitForK:
 ;The following code results in a sampling window of 1/4 bit which meets the spec.
     sbis    USBIN, USBMINUS
diff --git a/usbdrv/usbdrvasm128.inc b/usbdrv/usbdrvasm128.inc
index 8b19d69..2dd6fe1 100644
--- a/usbdrv/usbdrvasm128.inc
+++ b/usbdrv/usbdrvasm128.inc
@@ -107,10 +107,14 @@ USB_INTR_VECTOR:
 ;----------------------------------------------------------------------------
 ;sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
 ;sync up with J to K edge during sync pattern -- use fastest possible loops
-;first part has no timeout because it waits for IDLE or SE1 (== disconnected)
+;The first part waits at most 1 bit long since we must be in sync pattern.
+;YL is guarenteed to be < 0x80 because I flag is clear. When we jump to
+;waitForJ, ensure that this prerequisite is met.
 waitForJ:
-    sbis    USBIN, USBMINUS ;1 [40] wait for D- == 1
-    rjmp    waitForJ        ;2
+    sbic    USBIN, USBMINUS
+    rjmp    waitForK
+    inc     YL
+    brne    waitForJ        ; just make sure we have ANY timeout
 waitForK:
 ;The following code results in a sampling window of 1/4 bit which meets the spec.
     sbis    USBIN, USBMINUS
diff --git a/usbdrv/usbdrvasm15.inc b/usbdrv/usbdrvasm15.inc
index 689d2a3..a315eae 100644
--- a/usbdrv/usbdrvasm15.inc
+++ b/usbdrv/usbdrvasm15.inc
@@ -43,11 +43,14 @@ USB_INTR_VECTOR:
 ;
 ;   sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
 ;   sync up with J to K edge during sync pattern -- use fastest possible loops
-;   first part has no timeout because it waits for IDLE or SE1 (== disconnected)
-;-------------------------------------------------------------------------------
-waitForJ:			 ;- 
-    sbis    USBIN, USBMINUS      ;1 <-- sample: wait for D- == 1
-    rjmp    waitForJ		 ;2 
+;The first part waits at most 1 bit long since we must be in sync pattern.
+;YL is guarenteed to be < 0x80 because I flag is clear. When we jump to
+;waitForJ, ensure that this prerequisite is met.
+waitForJ:
+    sbic    USBIN, USBMINUS
+    rjmp    waitForK
+    inc     YL
+    brne    waitForJ        ; just make sure we have ANY timeout
 ;-------------------------------------------------------------------------------
 ; The following code results in a sampling window of < 1/4 bit 
 ;	which meets the spec.
diff --git a/usbdrv/usbdrvasm16.inc b/usbdrv/usbdrvasm16.inc
index 44b00fa..b59f74d 100644
--- a/usbdrv/usbdrvasm16.inc
+++ b/usbdrv/usbdrvasm16.inc
@@ -41,10 +41,14 @@ USB_INTR_VECTOR:
 ;----------------------------------------------------------------------------
 ;sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
 ;sync up with J to K edge during sync pattern -- use fastest possible loops
-;first part has no timeout because it waits for IDLE or SE1 (== disconnected)
+;The first part waits at most 1 bit long since we must be in sync pattern.
+;YL is guarenteed to be < 0x80 because I flag is clear. When we jump to
+;waitForJ, ensure that this prerequisite is met.
 waitForJ:
-    sbis    USBIN, USBMINUS     ;[-18] wait for D- == 1
-    rjmp    waitForJ
+    sbic    USBIN, USBMINUS
+    rjmp    waitForK
+    inc     YL
+    brne    waitForJ        ; just make sure we have ANY timeout
 waitForK:
 ;The following code results in a sampling window of < 1/4 bit which meets the spec.
     sbis    USBIN, USBMINUS     ;[-15]
diff --git a/usbdrv/usbdrvasm165.inc b/usbdrv/usbdrvasm165.inc
index b37ac96..acad899 100644
--- a/usbdrv/usbdrvasm165.inc
+++ b/usbdrv/usbdrvasm165.inc
@@ -46,10 +46,14 @@ USB_INTR_VECTOR:
 ;----------------------------------------------------------------------------
 ;sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
 ;sync up with J to K edge during sync pattern -- use fastest possible loops
-;first part has no timeout because it waits for IDLE or SE1 (== disconnected)
+;The first part waits at most 1 bit long since we must be in sync pattern.
+;YL is guarenteed to be < 0x80 because I flag is clear. When we jump to
+;waitForJ, ensure that this prerequisite is met.
 waitForJ:
-    sbis    USBIN, USBMINUS     ;[-18] wait for D- == 1
-    rjmp    waitForJ
+    sbic    USBIN, USBMINUS
+    rjmp    waitForK
+    inc     YL
+    brne    waitForJ        ; just make sure we have ANY timeout
 waitForK:
 ;The following code results in a sampling window of < 1/4 bit which meets the spec.
     sbis    USBIN, USBMINUS     ;[-15]
diff --git a/usbdrv/usbdrvasm20.inc b/usbdrv/usbdrvasm20.inc
index 2d4be52..ebe14e2 100644
--- a/usbdrv/usbdrvasm20.inc
+++ b/usbdrv/usbdrvasm20.inc
@@ -57,10 +57,14 @@ USB_INTR_VECTOR:
 ;----------------------------------------------------------------------------
 ;sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
 ;sync up with J to K edge during sync pattern -- use fastest possible loops
-;first part has no timeout because it waits for IDLE or SE1 (== disconnected)
+;The first part waits at most 1 bit long since we must be in sync pattern.
+;YL is guarenteed to be < 0x80 because I flag is clear. When we jump to
+;waitForJ, ensure that this prerequisite is met.
 waitForJ:
-    sbis    USBIN, USBMINUS     ;[-21] wait for D- == 1
-    rjmp    waitForJ
+    sbic    USBIN, USBMINUS
+    rjmp    waitForK
+    inc     YL
+    brne    waitForJ        ; just make sure we have ANY timeout
 waitForK:
 ;The following code results in a sampling window of < 1/4 bit which meets the spec.
     sbis    USBIN, USBMINUS     ;[-19]