+++ /dev/null
-/* Name: asmcommon.inc
- * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
- * Author: Christian Starkjohann
- * Creation Date: 2007-11-05
- * 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: $Id$
- */
-
-/* Do not link this file! Link usbdrvasm.S instead, which includes the
- * appropriate implementation!
- */
-
-/*
-General Description:
-This file contains assembler code which is shared among the USB driver
-implementations for different CPU cocks. Since the code must be inserted
-in the middle of the module, it's split out into this file and #included.
-
-Jump destinations called from outside:
- sofError: Called when no start sequence was found.
- se0: Called when a package has been successfully received.
- overflow: Called when receive buffer overflows.
- doReturn: Called after sending data.
-
-Outside jump destinations used by this module:
- waitForJ: Called to receive an already arriving packet.
- sendAckAndReti:
- sendNakAndReti:
- sendCntAndReti:
- usbSendAndReti:
-
-The following macros must be defined before this file is included:
- .macro POP_STANDARD
- .endm
- .macro POP_RETI
- .endm
-*/
-
-#define token x1
-
-overflow:
- ldi x2, 1<<USB_INTR_PENDING_BIT
- USB_STORE_PENDING(x2) ; clear any pending interrupts
-ignorePacket:
- clr token
- rjmp storeTokenAndReturn
-
-;----------------------------------------------------------------------------
-; Processing of received packet (numbers in brackets are cycles after center of SE0)
-;----------------------------------------------------------------------------
-;This is the only non-error exit point for the software receiver loop
-;we don't check any CRCs here because there is no time left.
-se0:
- subi cnt, USB_BUFSIZE ;[5]
- neg cnt ;[6]
- sub YL, cnt ;[7]
- sbci YH, 0 ;[8]
- ldi x2, 1<<USB_INTR_PENDING_BIT ;[9]
- USB_STORE_PENDING(x2) ;[10] clear pending intr and check flag later. SE0 should be over.
- ld token, y ;[11]
- cpi token, USBPID_DATA0 ;[13]
- breq handleData ;[14]
- cpi token, USBPID_DATA1 ;[15]
- breq handleData ;[16]
- lds shift, usbDeviceAddr;[17]
- ldd x2, y+1 ;[19] ADDR and 1 bit endpoint number
- lsl x2 ;[21] shift out 1 bit endpoint number
- cpse x2, shift ;[22]
- rjmp ignorePacket ;[23]
-/* only compute endpoint number in x3 if required later */
-#if USB_CFG_HAVE_INTRIN_ENDPOINT || USB_CFG_IMPLEMENT_FN_WRITEOUT
- ldd x3, y+2 ;[24] endpoint number + crc
- rol x3 ;[26] shift in LSB of endpoint
-#endif
- cpi token, USBPID_IN ;[27]
- breq handleIn ;[28]
- cpi token, USBPID_SETUP ;[29]
- breq handleSetupOrOut ;[30]
- cpi token, USBPID_OUT ;[31]
- brne ignorePacket ;[32] must be ack, nak or whatever
-; 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 from the start of
-;the sync pattern until the first bit is sampled. That's a total of 56 cycles.
-handleSetupOrOut: ;[32]
-#if USB_CFG_IMPLEMENT_FN_WRITEOUT /* if we have data for endpoint != 0, set usbCurrentTok to address */
- andi x3, 0xf ;[32]
- breq storeTokenAndReturn ;[33]
- mov token, x3 ;[34] indicate that this is endpoint x OUT
-#endif
-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
- reti
-
-handleData:
-#if USB_CFG_CHECK_CRC
- CRC_CLEANUP_AND_CHECK ; jumps to ignorePacket if CRC error
-#endif
- lds shift, usbCurrentTok;[18]
- tst shift ;[20]
- breq doReturn ;[21]
- lds x2, usbRxLen ;[22]
- tst x2 ;[24]
- brne sendNakAndReti ;[25]
-; 2006-03-11: The following two lines fix a problem where the device was not
-; 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, shift ;[30]
- lds x2, usbInputBufOffset;[32] swap buffers
- ldi cnt, USB_BUFSIZE ;[34]
- sub cnt, x2 ;[35]
- sts usbInputBufOffset, cnt;[36] buffers now swapped
- rjmp sendAckAndReti ;[38] 40 + 17 = 57 until SOP
-
-handleIn:
-;We don't send any data as long as the C code has not processed the current
-;input data and potentially updated the output data. That's more efficient
-;in terms of code size than clearing the tx buffers when a packet is received.
- lds x1, usbRxLen ;[30]
- cpi x1, 1 ;[32] negative values are flow control, 0 means "buffer free"
- brge sendNakAndReti ;[33] unprocessed input packet?
- ldi x1, USBPID_NAK ;[34] prepare value for usbTxLen
-#if USB_CFG_HAVE_INTRIN_ENDPOINT
- andi x3, 0xf ;[35] x3 contains endpoint
-#if USB_CFG_SUPPRESS_INTR_CODE
- brne sendNakAndReti ;[36]
-#else
- brne handleIn1 ;[36]
-#endif
-#endif
- lds cnt, usbTxLen ;[37]
- sbrc cnt, 4 ;[39] all handshake tokens have bit 4 set
- rjmp sendCntAndReti ;[40] 42 + 16 = 58 until SOP
- sts usbTxLen, x1 ;[41] x1 == USBPID_NAK from above
- ldi YL, lo8(usbTxBuf) ;[43]
- ldi YH, hi8(usbTxBuf) ;[44]
- rjmp usbSendAndReti ;[45] 57 + 12 = 59 until SOP
-
-; Comment about when to set usbTxLen to USBPID_NAK:
-; We should set it back when we receive the ACK from the host. This would
-; be simple to implement: One static variable which stores whether the last
-; tx was for endpoint 0 or 1 and a compare in the receiver to distinguish the
-; ACK. However, we set it back immediately when we send the package,
-; assuming that no error occurs and the host sends an ACK. We save one byte
-; RAM this way and avoid potential problems with endless retries. The rest of
-; the driver assumes error-free transfers anyway.
-
-#if !USB_CFG_SUPPRESS_INTR_CODE && USB_CFG_HAVE_INTRIN_ENDPOINT /* placed here due to relative jump range */
-handleIn1: ;[38]
-#if USB_CFG_HAVE_INTRIN_ENDPOINT3
-; 2006-06-10 as suggested by O.Tamura: support second INTR IN / BULK IN endpoint
- cpi x3, USB_CFG_EP3_NUMBER;[38]
- breq handleIn3 ;[39]
-#endif
- lds cnt, usbTxLen1 ;[40]
- sbrc cnt, 4 ;[42] all handshake tokens have bit 4 set
- rjmp sendCntAndReti ;[43] 47 + 16 = 63 until SOP
- sts usbTxLen1, x1 ;[44] x1 == USBPID_NAK from above
- ldi YL, lo8(usbTxBuf1) ;[46]
- ldi YH, hi8(usbTxBuf1) ;[47]
- rjmp usbSendAndReti ;[48] 50 + 12 = 62 until SOP
-
-#if USB_CFG_HAVE_INTRIN_ENDPOINT3
-handleIn3:
- lds cnt, usbTxLen3 ;[41]
- sbrc cnt, 4 ;[43]
- rjmp sendCntAndReti ;[44] 49 + 16 = 65 until SOP
- sts usbTxLen3, x1 ;[45] x1 == USBPID_NAK from above
- ldi YL, lo8(usbTxBuf3) ;[47]
- ldi YH, hi8(usbTxBuf3) ;[48]
- rjmp usbSendAndReti ;[49] 51 + 12 = 63 until SOP
-#endif
-#endif
projects / fnordlicht-mini / blobdiff