diff options
Diffstat (limited to 'firmware/usbdrv/usbdrvasm.S')
| -rw-r--r-- | firmware/usbdrv/usbdrvasm.S | 50 |
1 files changed, 22 insertions, 28 deletions
diff --git a/firmware/usbdrv/usbdrvasm.S b/firmware/usbdrv/usbdrvasm.S index 45fcf18..b03b709 100644 --- a/firmware/usbdrv/usbdrvasm.S +++ b/firmware/usbdrv/usbdrvasm.S @@ -5,7 +5,6 @@ * Tabsize: 4 * Copyright: (c) 2007 by OBJECTIVE DEVELOPMENT Software GmbH * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt) - * Revision: $Id: usbdrvasm.S 785 2010-05-30 17:57:07Z cs $ */ /* @@ -285,7 +284,7 @@ usbCrc16Append: #if USB_CFG_HAVE_MEASURE_FRAME_LENGTH #ifdef __IAR_SYSTEMS_ASM__ -/* Register assignments for usbMeasureFrameLength on IAR cc */ +/* Register assignments for usbMeasureFrameLengthDecreasing on IAR cc */ /* Calling conventions on IAR: * First parameter passed in r16/r17, second in r18/r19 and so on. * Callee must preserve r4-r15, r24-r29 (r28/r29 is frame pointer) @@ -314,33 +313,28 @@ usbCrc16Append: #endif # define cnt16 cnt16L -; extern unsigned usbMeasurePacketLength(void); -; returns time between two idle strobes in multiples of 7 CPU clocks -.global usbMeasureFrameLength -usbMeasureFrameLength: - ldi cntH, 6 ; wait ~ 10 ms for D- == 0 - clr cnt16L - clr cnt16H -usbMFTime16: - dec cntH - breq usbMFTimeout -usbMFWaitStrobe: ; first wait for D- == 0 (idle strobe) - sbiw cnt16, 1 ;[0] [6] - breq usbMFTime16 ;[2] - sbic USBIN, USBMINUS ;[3] - rjmp usbMFWaitStrobe ;[4] -usbMFWaitIdle: ; then wait until idle again +; extern int usbMeasurePacketLengthDecreasing(int); +; input: timer start value +; return: counts down time between two idle strobes in multiples of 5 CPU clocks +.global usbMeasureFrameLengthDecreasing +usbMeasureFrameLengthDecreasing: + +#if resL != cnt16L + mov cnt16L, resL + mov cnt16H, resH +#endif + +usbDFWaitStrobe: ; first wait for D- == 0 (idle strobe) + sbic USBIN, USBMINUS ; + rjmp usbDFWaitStrobe ; +usbDFWaitIdle: ; then wait until idle again sbis USBIN, USBMINUS ;1 wait for D- == 1 - rjmp usbMFWaitIdle ;2 - ldi cnt16L, 1 ;1 represents cycles so far - clr cnt16H ;1 -usbMFWaitLoop: - in cntH, USBIN ;[0] [7] - adiw cnt16, 1 ;[1] - breq usbMFTimeout ;[3] - andi cntH, USBMASK ;[4] - brne usbMFWaitLoop ;[5] -usbMFTimeout: + rjmp usbDFWaitIdle ;2 +usbDFWaitLoop: + sbiw cnt16,1 ;[0] [5] + sbic USBIN, USBMINUS ;[2] + rjmp usbDFWaitLoop ;[3] + #if resL != cnt16L mov resL, cnt16L mov resH, cnt16H |